Compression Test Results.

BosnianLanos · Post by **BosnianLanos** » Sat May 24, 2008 11:10 pm

I tested the compression on my '99 Lanos today. Ran it up to operating temperature, pulled the plugs and the coil and went to town.

Results are as follows:

Cylinder 4: 150 PSI
Cylinder 3: 150 PSI
Cylinder 2: 145 PSI
Cylinder 1: 135 PSI

I think these are pretty decent numbers for a 10 year old engine with 205,000 miles. I'm not sure what OEM pressure is, but I don't think these are too far off... Do you guys see any problems with these numbers?

exist3nce · Post by **exist3nce** » Sat May 24, 2008 11:31 pm

Looks pretty reasonable to me especially for 200k+ miles!

MMamdouh · Post by **MMamdouh** » Sun May 25, 2008 7:03 am

i think i cam across a statment in the service manual saying that the difference between the highest and lowest pressure should not exceed 25%... you have that covered

i am not sure of the correct PSI either

MMamdouh

buddha102 · Post by **buddha102** » Tue May 27, 2008 2:22 am

well if it drives then its ok, but 2-4 cyl are good (2 is not way off from other ones), but cyl #1 well u have to check it

daewoomofo · Post by **daewoomofo** » Tue May 27, 2008 9:11 am

cyl 1 is still ok. like mm said if you are less than 25% away from each other you are fine. 135 isnt that far away from 150.

BosnianLanos · Post by **BosnianLanos** » Tue May 27, 2008 4:18 pm

I figured that with only 10% spread in the numbers it was fine. I was just worried that I might find out that stock pressure is like 180 PSI in each cylinder.

But I drove it all over town last night. Put 60 miles on it, apart from some minor oil leaks from the valve cover bolts, it ran like a beast and was very reliable. There wasn't a single moment where I thought "Oh shit, this thing is gonna die on me", and that means a lot.