Please help!!!Compression test question.
Thread Starter
Advanced
Joined: Nov 2005
Posts: 99
Likes: 0
From: Gulfport FL
Please help!!!Compression test question.
I noticed a coolant leak last week and traced it towards the front of the passenger side cylinder head. After more investigation, I found there to be a coolant leak on the front of the passenger side intake manifold gasket..where it meets the head. Now I know that this could be the cause of my rough idle ever since the leak got worst(loss of vacuum)....however could this also be the cause of low compression in cylinder number 2(90 psi). I checked compression on cylinder number 4 next to number 2 and it was 135 lbs(somewhat below normal) I checked it on the other bank, number 1 and it was 155 lbs, which I believe is normal. Is there ANY way this could be caused by the intake leak, or do you think it is a separate leak such as : head gasket, valves, or piston rings????? Thanks for your assistance anyone!!!!
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Its pretty tough to tell without being there in person; and even then I would recommend pulling the intake a minimum and replacing all the gaskets with premium good ones with a light coat of "the right stuff" gasket sealer.
The intake in and of itself should not effect the compression reading your getting unless some of the cylinder are getting fluid in them from coolant leaking, this would raise the readings.....
Redo the intake gaskets and go from there...
The intake in and of itself should not effect the compression reading your getting unless some of the cylinder are getting fluid in them from coolant leaking, this would raise the readings.....
Redo the intake gaskets and go from there...
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
If you suspect a leak between the coolant and combustion chamber, either pressurize the cooling system and let it set. Then see if the water hydro locks the cylinder. Or take the spark plug out and with an adapter, apply air pressure. Then with the radiator cap loose, look for bubbles.
If either of these work, its a pretty sure bet that you have a blown head gasket or possibably a cracked head etc.
But unless the engine has extremely overheated, Ill bet on the headgasket.
If either of these work, its a pretty sure bet that you have a blown head gasket or possibably a cracked head etc.
But unless the engine has extremely overheated, Ill bet on the headgasket.
