When should you do a compression test on an engine?

What you're looking for during the test is abnormally low numbers or numbers which don't line up.

If one or more pistons are making 10% less compression than the others, then it's time to do a wet test.

A little bit of oil is added to the offending cylinders, then the compression is checked again.

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When doing a compression test on a gas engine do you start the engine?

No, The compression test is done as the starter cranks the engine

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Can I do a compression test on a cold engine?

You can do it warm or cold - your choice.Working over a cold engine is safer and more comfortable than working over a warm engine.If the engine appears to have a serious problem and all you are looking for is a gross problem like a blown head gasket or burnt valve, do the test cold.

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When performing a compression test the readings should be?

All cylinders should be within 10% of each other.

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Do you use compressed air or oil to do leak down test on a car engine?

just air with all the plugs out

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How much should a compression test cost?

Compression Test Service Costs When having a compression test done by a repair shop the costs will vary depending on how many cylinders your car's engine has and how difficult the sparkplugs are to remove.Most shops will charge about $80.00 for a 4 cylinder and about $140.00 (US) for V8 engine's.

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How much compression should an engine have?

A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly.Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.

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Can low compression on an engine damage a engine?

Low compression indicates that engine damage already exists. An engine's compression will be lost if: there is damage or wear to the pistons or rings there is damage or wear to the valve train there is damage or loss of seal on the cylinder head There are some other factors as well, but these thr...

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Why do you need compression in an engine?

The higher compression the engine the more power it can theoretically produce. The compression ratio is mainly determined by the type of fuel being used.

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How do you lower the compression ratio of an engine?

There are several means by which the compression ratio of an engine might be reduced although all involve extensive mechanical rework to accomplish.1) Remove the heads from the motors and grind the compression chambers of the head(s) to make the area larger.2) Install replacement pistons that hav...

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How do you disengage fuel and spark for a compression test on a 1994 civic?

pretty much only way to stop the fuel, is if you have an electric fuel pump, you can remove fuel pump fuse.but you really dont need to do this for a compression test. in performing a compression test, you need to remove spark plugs to use compression gage. before you start, remove the lead that g...

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What does a compression test tell you?

A compression test can tell you many things such as if you're getting blow by. which means one of two things either all the compression ring gaps on the piston line up in sync or possibly you have a crack in your cylinder. Also if you have the distributor shaft apart from the engine a compression...

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Can peeing in a gas tank or on an engine cause lost engine compression?

Into the gas tank; no. Any volume of fluid being poured directly into the combustion chamber of the engine can cause the destruction of the pistons, which will lead to compression loss (among other more severe side effects).

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What does a car compression test tell you?

How well the combustion chambers hold pressure. It's a good indication of overall engine wear and condition.

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Is a leak down test better than a compression test?

One test result where a compression tester can be as good as a leak-down test: If two cylinders side-by-side have lower compression than the rest, the most likely cause is a blown head gasket between the cylinders.You can perform a leak-down test with the piston at bottom dead center.

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Does stroking an engine increase compression?

You can either raise/lower the compression by stroking the motor based on how you set it up.If you keep the same chamber volume and increase the compression volume it will increase the Compression RATIO.

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You did a compression test and have 195lbs what is the compression of the pistions?

There is no possible way to answer that question based on just PSI.Try googling compression ratio calculator. Once opening the first result you will need to enter your engine specifications to find out the answer. You will need to know the bore, stroke, gasket thickness, size of the combustion ch...

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If an engine has a compression ratio of 7.1?

Depends on the make of engine, but that sounds about normal .

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Can you fix an engine with low compression?

Fixing low compression Once you know low compression is an issue and have it narrowed down to which cylinder it is fixing it isn't that hard.You have to inspect each part of the cylinder.Check the valves to make sure they are not damaged, check the piston and piston rings, and check the head gas...

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What does a compression test determine?

A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly.Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.

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How do you increase engine compression ratio?

To decrease the compression ratio "remove material" from inside of the Cylinder head or piston top. This increases both the volumes by equal amount and hence the ratio gets decreased. Changing the piston head design.Changing the stroke length of the cylinder.Changing cylinder diameter.Chang...

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How much compression should a diesel engine have?

Compression ratios are often between 14:1 and 23:1 for direct injection diesel engines, and between 18:1 and 23:1 for indirect injection diesel engines.Since diesel engines operate on the principle of compression ignition, a fuel which resists autoignition will cause late ignition, which can lead...

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Can you have good compression on an engine with defective valves?

no if the valves do not seat properly against the head the piston will force the fuel mixture past either into the exhaust or the intake if the vehicle is running rich i would suspect the intake valves

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How do you lower engine compression?

You usually lower engine compression by using head spacers between the engine block and head or by using shorter pistons.

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How do you calculate engine compression ratio?

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How do you measure engine compression?

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What makes an engine lose compression?

Worn cylinder bore, worn piston rings, poor valve seat condition, tired valve springs.

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Does boring an engine increase compression?

One of us says boring an engine will cause a lower compression ratio because of a bigger cylinder area.One of us says the compression ratio remains the same because along with the bigger bore is a bigger piston to compress more air.

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What will a compression test tell me?

What will a compression test tell me? Low compression in one cylinder usually indicates a bad exhaust valve.Low compression in two adjacent cylinders typically means you have a bad head gasket.Low compression in all cylinders would tell you the rings and cylinders are worn and the engine needs t...

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What is a good compression test reading?

As a general rule a compression of 135 PSI or better is excellent.Similarly, A compression of 85 PSI or lower is extremely bad.The most desirable situation is that all cylinders give the same or close to the same reading.Furthermore, That reading should be above 135 PSI.

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Will an engine run with low compression?

An engine with low compression in one cylinder will present itself by having a misfire and running rough while no compression in all cylinders will cause the engine not to start.There are many different low compression symptoms which will cause the engine to run abnormally.

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How do you test an alternator on motorcycle?

put a voltmeter on the battery and test voltage, then start the cycle and check again.A battery at rest should be at about 13 volts, with the engine running it will be at 14 or above.to be sure disconnect the positive battery terminal while running, if there is still good volts there, or the engi...

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How do you test wastegate on caterpillar c-13 engine?

you apply 22 psi to the hose and it should move

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When starting engine popped and lost compression?

It could be a variety of things. easy stuff to check for include making sure all our spark plugs are there and tight, or any kind of leak around the head gasket.If you haven't already, you can get a shop to run a compression test (to verify the spark plug connection) or pressurize the system to s...

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When should you use a and an?

An is generally used when the next word begins with a vowel [A E I O U]. While a is used for consonantsExamples for an:That is an alligator.I am an extra in that movie.etc.Examples for a:This is a home.Where is there a bathroom?Abbreviations have a somewhat different rule, however!For "A, E, I, a...

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Can you test an engine outside of the vehicle?

Mechanics and engineers often use a test stand to test an engine. It provides the fuel and other connections to test horsepower and proper assembly.

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When you encounter large trucks on an expressway what should you do?

avoid driving between two trucks.

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What happens when your engine loses compression?

This results in compression loss.The exhaust valve fails most often because it is exposed to the hot exhaust gases, which reach up to 1,200 to 1,350 degrees.The heated valve breaks or warps, causing leaks in the cylinder and compression loss.Valves can also acquire carbon buildup.

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Will a compression test show a bad valve?

Wet Compression Test Diagnosis If the compression increases, the piston rings are at fault.Burned valves: If the results remain the same, one of the valves are bad or not seating correctly.Low compression in only one cylinder typically indicates a bad valve.Exhaust valves burn due to hot gases p...

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Will an engine with low compression idle smoothly?

No. It won't have enough compression to fire the cylinder to burn the fuel and air mixture thus creating a "miss".

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How do you do engine block test?

First you need a Block Tester (or any other combustion leak tester). The idea is you create an air pocket in the top of your radiator by draining the coolant to lower the coolant level a couple of inches. Then with the engine warm (not overheating!) and idling, you "sample" air through the Block ...

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What is the difference between a compression test and a leak down test?

A compression test uses the engine turning to generate the compression in the cylinder for the compression stroke, in which both intake and exhaust valves are closed.A leak down test uses a set of gauges and pressurizes the cylinder with air and measures how much of that air is escaping.

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How do you test an ignition switch?

How to Test an Ignition Switch Open the fuse panel under the steering wheel and pull the fuse for the starter signal using the fuse pullers in the panel.Check the metal strip in the fuse to make sure that the strip is not burned or damaged. Open the hood and turn the dial on the voltmeter to...

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How do I change the compression ratio on my engine?

To decrease the compression ratio "remove material" from inside of the Cylinder head or piston top. This increases both the volumes by equal amount and hence the ratio gets decreased. Changing the piston head design.Changing the stroke length of the cylinder.Changing cylinder diameter.Chang...

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How do you test an ASD relay?

Connect the ohmmeter between terminals 87 and 30.The ohmmeter should not show continuity at this time.Connect one end of a jumper wire (16 gauge or smaller) to relay terminal 85.Connect the other end of the jumper wire to the ground side of a 12-volt power source.

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How do you test an accelerator pump?

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How do you test an automotive relay?

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How do you test an auto relay?

A car relay is a remote control switch that controls electrical components. To see how you should test yours, check your owners manual.Simply swap it with another like relay.

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How do you test an antenna?

TEST 1.Connect one lead from the meter to the tip of the antenna, and the other to the radio pin -- the piece at the end of the antenna cable that fits into the radio.The reading should be low, usually under 5 ohms; that means a good electrical connection between the tip of the antenna and the ra...

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What is the minimum compression for an engine to run?

Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.

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How do you test an ignition condenser?

Touch the red lead to the hot connector on the condenser.Place the black lead to the metal case on the condenser.The meter's needle should jump slightly to the right (toward 0-ohms), then should drop back to the left towards infinite resistance).Hold the leads in place for 15 to 20 seconds.

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How do you test a bad diode in an alternator?

* To check for a possible bad alternator diode, switch your voltmeter to a low setting on the AC (alternating current) voltage scale.* With the engine running, touch the meter probes to the battery terminals.Any amount of AC voltage would indicate a bad diode, so you'll need to replace the altern...

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Why do engine looses compression?

smalltime here, generally your compression rings on your pistons are shot ormabey worse case senerio cracked block! hope this helps. smalltime.

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What should you do when driving in an urban area?

Go slow and be careful?

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What should you do when an emergency vehicle is coming with flashing light on?

State law requires drivers approaching a stationary emergency vehicle displaying flashing lights, including road service vehicles, traveling in the same direction, to vacate the lane closest to if safe and possible to do so, or slow to a speed safe for road, weather, and traffic conditions.

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Should you rebuild an engine or buy a new car?

While purchasing a brand new car may seem to be the more expensive option, merely repairing the engine could cost more in the long run. Repairing a car's engine runs the risk of the engine breaking down again and some engines, especially old ones, may be beyond repair and trying to do so would be...

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What will be the effect of low compression on an engine?

Low Engine Compression will Cause a Misfire An engine with low compression in one cylinder will present itself by having a misfire and running rough while no compression in all cylinders will cause the engine not to start.There are many different low compression symptoms which will cause the eng...

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What is the compression on a 1995 wildcat 700 engine?

120 P.S.I. is acceptable low, 130 is good 135 is factory startup/breakin period required.

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When you approach an intersection you should?

When driving up to the intersection signal your intention for at least three seconds if you are turning.If you are passing straight through an intersection check left and right in case another vehicle runs a red light, or is likely to pull out in front of you.

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When facing a head-on collision what should you do?

Assuming the question means you cannot avoid the collision:Brake, leave the car in gear if manual, and keep in a straight line. Your car is designed to absorb straight on impacts much more safely then rotational impacts, so if you must take a hit, do so straight on.

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What else should I replace When replacing an engine?

Timing belts/chains, water pump, thermostat, spark plugs, fluids, and seals are routine maintenance items and should be replaced at the time of installation and at the vehicle manufacturer's recommended service intervals.Replace any water hoses or vacuum lines that need replacing.

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What happens to an engine with compression loss?

broken rings,hole in piston,bad valves

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What causes lack of compression in an engine?

Lack of compression might occur for these reasons: Your piston rings are worn (allowing the air/fuel mix to leak past the piston during compression).The intake or exhaust valves are not sealing properly, again allowing a leak during compression.There is a hole in the cylinder.

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What procedure should be carried out for a new diesel engine or an engine that has been out service before starting using compress air?

please follow the below procedure.# check engine lube oil level. # check engine coolant level and related to the cooling system # lubricate the engine main bearing using some external pump, you can connect the pump to the lube oil gallery or if there is a pump on the engine then prime the lube oi...

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How much does a compression and Leakdown test cost?

The average cost for an engine compression test is between $181 and $220.Labor costs are estimated between $128 and $162 while parts are priced between $53 and $58.

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Should you engine brake on a motorcycle?

The answer is generally no.When using the brakes, you are under full control of your motorcycle and are able to influence the speed of your vehicle with accuracy.Much less so when using engine braking only.Another, potentially more dangerous issue is the absence of the brake light.

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Should Battery light on when engine running?

No; this should not be happening. Take your car into a local auto parts store and have them test your battery and alternator.PaulTuff Play - Your Playground Provider

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What should you do when an emergency vehicle with a siren and flashing lights approaches you?

What should you do if an emergency vehicle approaches you with lights flashing and siren sounding? Speed up to stay in front of the vehicle.Pull over to the side of the road and stop until all emergency vehicles are safely by.Let them pass and follow the vehicle to the scene of the emergency.

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How can you increase the compression ratio of an internal combustion engine?

Compression ratio (CR) is the total volume of a cylinder at BDC (bottom dead center) divided by total volume of space at TDC (top dead center).To increase CR, you must either increase the total volume of displacement, or decrease the volume at TDC. This can be achieved by shaving the heads, incre...

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When removing an engine do you need the wiring harness?

If you are installing the engine in an exact model that the engine is coming out of, the harness should not be needed. If there are any changes in model, sensors or anything else then the harnesses will not be interchangeable.

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Can you fix low engine compression?

Fixing low compression Once you know low compression is an issue and have it narrowed down to which cylinder it is fixing it isn't that hard.You have to inspect each part of the cylinder.Check the valves to make sure they are not damaged, check the piston and piston rings, and check the head gas...

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When should you call an ambulance?

A person's condition is potentially life-threatening.They could be experiencing chest pains, difficulty breathing, sudden confusion or an altered mental status.These symptoms could be signs of heart attack, stroke, or related conditions and immediate medical attention may be required.Call 911 and...

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WHEN ENTERING A STREET FROM AN UNPAVED ROAD YOU SHOULD...?

Look both ways before entering.

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What precautions should you take when entering an intersection on a green light?

Naturally one (experienced driver) always has to be aware of suroundings, keep eyes peeled to intersections re: cars who may run red light and go through your green. Green doesn't mean go, it means go when safe and logical...and don't doddle, either. Anticipate early, experience and years on road...

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When turning right on a red light at an intersection you should?

Before you do anything you must obey the red light and come to a complete stop in the rightmost lane with your turn signal on.Make sure you stop behind the limit line (or crosswalk or intersection if there is no line).There's no need to roll the stop and end up with a ticket or cause a collision.

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When do you change an air filter on a car?

when you start having breathing problems

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When running an automobile in a closed area you should?

Avoid turning on the car A/C and open the windows to prevent carbon monoxide poisoning.Ventilate the area and/or attach an exhaust hose extension leading outdoors.

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When an emergency vehicle approaches with a siren you should?

If an emergency vehicle approaches you from any direction with its lights flashing or siren/bell sounding you should immediately bring your vehicle to a complete stop.

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When do you need a goods vehicle test certificate?

obviously because to check the amount of emissions from our vehicles . no check eventually leads to more air pollution.

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Can you pass emissions test with check engine light on?

In most cases, your car will pass unless the check-engine light is on when you pull into the test facility.After your car is repaired, the technician will erase the trouble codes from the computer.That's good because your car will fail the emissions retest if any trouble codes are present.

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What should you do when an emergency vehicle is approaching while crossing an intersection?

You are crossing an intersection and an emergency vehicle is approaching with a siren and flashing lights. You should: Stop immediately in the intersection until it passes. Must always stop before driving through the intersection.Must yield the right-of-way to all other vehicles.Should slow...

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Is a high compression engine better?

Automotive engineers can improve fuel efficiency and fuel economy by designing engines with high compression ratios.The higher the ratio, the more compressed the air in the cylinder is.It's the same thing with compression ratios.By keeping the explosion in a smaller space, more of its power can b...

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A smoothly operating engine depends high compression?

It depends on equal compression between all cylinders.

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What happens when you lose compression in a cylinder?

This results in compression loss.The exhaust valve fails most often because it is exposed to the hot exhaust gases, which reach up to 1,200 to 1,350 degrees.The heated valve breaks or warps, causing leaks in the cylinder and compression loss.Valves can also acquire carbon buildup.

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How do I do an on board diagnostic test for a 1995 GMC Safari Van?

Use a code reader. You can get it scanned at most chain autoparts stores for free.

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How many bolt should be inside a engine block when mounted on a engine stand?

4 bolts should be holding the engine to the engine stand.

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How do you install an engine oil dipstick on a smallblock 305 engine?

Drive it into the hole in the block. You can take a slightly larger piece of tubing and cut it at an angle to serve as a punch. Lube the dipstick tube and the hole in the block. Make sure your dipstick tube is correct for the engine.. for example, the tube used on 1-piece rear seal blocks is smal...

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How do you test a vacuum modulator on a transmission?

Testing the Modulator Block the rear wheels. Locate the vacuum modulator on the passenger side rear of the transmission. Pull the vacuum hose off the modulator and install the vacuum pump. Look for any transmission fluid running out of the vacuum port on the modulator, indicating a broken ...

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When approaching an intersection you should never pass when within?

When approaching within one hundred feet of or at any intersection or railroad grade crossing; or.When there is a solid yellow line.The following right-of-way rules apply at intersections: Drivers must yield where necessary to avoid striking pedestrians who are legally crossing the road.

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A technician is troubleshooting a driver complaint on an engine in a piece of equipment what should he do first?

Verify the complaint while the driver is present, and if possible replicate it.

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How do you fix AC that stops blowing when engine is under a load on an 02 Ranger 3.0?

Many vehicles were engineered that way so that you could get all of the power you need when passing or climbing a hill.

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How do you test an MSD ignition box?

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How do you test a speed sensor on a car?

Vehicle Speed Sensor Testing Turn the ignition switch to the OFF position.Disengage the wiring harness connector from the VSS.Using a Digital Volt-Ohmmeter (DVOM), measure the resistance (ohmmeter function) between the sensor terminals. If the resistance is 190–250 ohms, the sensor is okay.

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How do you test an oil pressure switch?

How to Test an Oil Pressure Sensor Insert the key into the ignition, and turn the key to the accessory setting. The engine should not be running.Look at the oil gauge on the dashboard. Unplug the wire that is connected to the sending unit, if the gauge is at zero.

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How do you test a distributor on a 1971 Nova?

With a dwell meter you could monitor the dwell angle. If the dwell fluctuates the distributor shaft and bushings are probably worn out. The dwell should be between 28 and 32 degrees and not fluctuate.

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Should you use thicker oil in an older engine?

heavier oils actually INCREASE the wear.thinner oils flow faster and lubricate better, and keep the engine parts cooler.using a thicker oil is asking for trouble.If a car NEW uses 5w 30, when it gets say 110,000 miles on it should you put 10w 40 in it?

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What happens when you have low compression?

Low compression in one cylinder usually indicates a bad exhaust valve.Low compression in two adjacent cylinders typically means you have a bad head gasket.Low compression in all cylinders would tell you the rings and cylinders are worn and the engine needs to be overhauled.

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Do brakes work when an engine stalls?

Yes they would still work, but it would be much harder to stop the vehicle because you don't have the booster powering the master cylinder, so you would have to push much harder on the brake pedal to stop.

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What happens when you start an engine?

The starter turns the flywheel, which turns the crankshaft that has the pistons connected to it. As the piston is pulled down the cylinder, air and fuel is pulled into the cylinder. The piston then travels up the cylinder and compresses the air/fuel mixture. When it reaches the top of the cylinde...

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How do you power an electric fan from the fuse box so it turns on when the engine is on?

with a test light check the fuses . find one that is hot only when the motor is running .

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How do you test if your engine is seized?

How to Tell If Your Car Engine Has Seized Put the emergency brake on and shift the car into neutral.Open the hood and locate the crankshaft pulley on your engine. Select a socket that fits the nut on the bolt in the center of the crankshaft pulley. Try to turn the crankshaft pulley in a clo...

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