Engine compression - Toyota Nation Forum : Toyota Car and Truck Forums

hdsalinas · 07-20-2004, 07:35 PM

Hi

i am taking my car to the shop this week and among the things I want them to do is to run a compression check on all 4 cylinders

How do they actually do this and how may psi per cylinder should be I be looking for in a 99 corolla?

Thanks

chronoti · 07-20-2004, 07:43 PM

they test it by removing the spark plug and put a gauge in it's place. then they turn the crank shaft and see what it goes too. i think they also leave it there for a moment to make sure it keeps at that pressure and what not .....

hdsalinas · 07-20-2004, 07:54 PM

oh, I see....

And what should be good numbers for my corolla?

homeguard · 07-20-2004, 07:55 PM

shouldnt all the cylinders be the same psi? and isnt it diff for all cars so whats like an adverage?

hdsalinas · 07-21-2004, 12:08 AM

I read while googling that on average they should be aroound 150psi. But they were talking about v6 engines and i dont know if it varies from one egine to the next. (especially when it is a smaller engine)

Can anyone confirm this?

thespud · 07-21-2004, 01:38 AM

Quote:

Originally posted by hdsalinas
I read while googling that on average they should be aroound 150psi. But they were talking about v6 engines and i dont know if it varies from one egine to the next. (especially when it is a smaller engine)

Can anyone confirm this?

I dont know the actual figure... but i do know that the difference between the best and worst should be no more than 9psi... if it is, one would suspect you have either cracked rings or a blown head gasket.

chronoti · 07-21-2004, 05:55 AM

yes i belive that they would differ from engine to engine depending on compression ratio's and what not