I have a 2009 Toyota Corolla and took a compression test first cylinder got 80 psi second cylinder got 80 psi as well third cylinder psi is 120 and forth cylinder got 130
Any ideas what I should do next ?
Do a leak-down test on the cylinders to determine why the compression is so low.
Tester
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Retest after putting a small amount of oil in the plug hole of the test cylinder. Compare the readings to the dry test. If they improve significantly, the rings are worn out. If they don’t increase, the valves are no longer sealing so you need a valve job.
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Did you do the compression test yourself as a diy’er? If so, suggest to tell us your test procedure. It is possible to get inccorect readings if done incorrectly. If experienced mechanic did the compression, your next practical step is probably installing a replacement engine.
What motivated this compression test in the first place? Did the engine oil level get very low, then the engine started running badly?
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Are you doing the compression test with the throttle blade 100% open??
And how many miles are on it???
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Yes I did it as a diyer did the compression test 3 times still 80 psi on one and two cylinder I also did a vacuum test vacuum which came out good
What made me do this test was I kept getting cylinder one misfire so I check spark plugs coil and as well fuel injector so I did a compression test
What I been hearing is it could be a head gasket but need to do a pressure test on cooling system to see if it could be that
A leak-down test also determines if there’s a head gasket leak.
Not only into the cooling system, but also between cylinders.
Tester
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I know that but don’t have the tools to do that so I’m doing the next thing I can do
I might consider driving it to my auto shop school to see if I can diagnostic test there
If you don’t have the tools. bring it to someone who does.
Especially if it’s free!
Tester
The other two cylinders have higher numbers, but are still too low to pass a compression test Iexpect. when engine was new, the compression was probably 185-190. Anything below 160 even on a used modern engine is suspect.
There’s three common mistakes that might cause a diy’er to get incorrect compression numbers. First, the compression gauge they are using is inaccurate. Second they didn’t open the throttle plate fully. Third, the battery wasn’t fully charged, preventing engine from cranking robustly. Given what you say however, I expect your numbers are accurate and the engine needs to be replaced or rebuilt.
I did that first took it to the delarship first that said compression was good supposedly wanted to charge more if keep looking supposedly so I deuces to take it somewhere els they said they couldn’t find the problem so I just do it myself
It seems odd you and dealership differ so much on compression numbers and their meaning. Good for you for taking on the job yourself, after losing trust in the dealership shop.
BTW, suggest to edit the language in above post. Remember, this is Car Talk website, and the language used should be within the limits of what you’d hear on the NPR radio program podcasts.
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Your language isn’t offensive to me.
That’s how real mechanics talk.
Tester
Does this engine have adjustable valves that use those shims . . . ?