Compression test numbers on a 91 runner
Dec 23, 2007 | 12:23 PM
#1
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Compression test numbers on a 91 runner
My truck quit running so in the process of diagnosing it I did a compressio n check. Here are the numbers
1= 120 2= 95
3= 85 4= 140
5= 140 6= 160
Would this be consistent with a head gasket problem or are these somewhat normal numbers for this engine?
The truck has 256k miles on it and the spark plugs definately need replacing (not sure when they were last done).... The don't look soaked or oily just a little burnt and carbon caked.
Thanks
Bill
1= 120 2= 95
3= 85 4= 140
5= 140 6= 160
Would this be consistent with a head gasket problem or are these somewhat normal numbers for this engine?
The truck has 256k miles on it and the spark plugs definately need replacing (not sure when they were last done).... The don't look soaked or oily just a little burnt and carbon caked.
Thanks
Bill
Dec 23, 2007 | 01:42 PM
#2
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Posts: 9,055
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From: maple ridge, British Columbia, Canada
Try putting a little bit of oil in there, if the compression goes up your valves need some work.
Doing a compression check is not a very good way to check for a hg failure.
Take out the plugs, unplug the coil and turn the engine over, if no water comes shooting out the plug holes you are fine.
Also if you indeed blow a hg the plug on that cylinder would be very white.
Doing a compression check is not a very good way to check for a hg failure.
Take out the plugs, unplug the coil and turn the engine over, if no water comes shooting out the plug holes you are fine.
Also if you indeed blow a hg the plug on that cylinder would be very white.
Dec 23, 2007 | 06:12 PM
#4
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From: WA ,monroe
Try putting a little bit of oil in there, if the compression goes up your valves need some work.
not exactly that usually means your rings if comp goes up when adding oil
Doing a compression check is not a very good way to check for a hg failure.
Take out the plugs, unplug the coil and turn the engine over, if no water comes shooting out the plug holes you are fine.
sorry but no... you can have a popped HG and have water in the oil or very little water in the cylinder not enough to notice when turning the motor over with the plugs out.
Also if you indeed blow a hg the plug on that cylinder would be very white.
not exactly that usually means your rings if comp goes up when adding oil
Doing a compression check is not a very good way to check for a hg failure.
Take out the plugs, unplug the coil and turn the engine over, if no water comes shooting out the plug holes you are fine.
sorry but no... you can have a popped HG and have water in the oil or very little water in the cylinder not enough to notice when turning the motor over with the plugs out.
Also if you indeed blow a hg the plug on that cylinder would be very white.
Dec 23, 2007 | 07:10 PM
#5
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From: kc mo
x's 2 and if addin oil makes the compression go up it means it may need rings not valve work. if you did a compression test you should pump up the cylinders and see where the air goes. that will tell you if it needs valve work and which one is bad.
Last edited by mr toytech; Dec 23, 2007 at 07:14 PM.
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