ClubWRX Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Hi everybody I recently cleaned my aos and replaced my hoses for the top mount intercooler after putting everything back I got the lean code. After diag and checking for leaks the only thing I could think of was the pcv valve so i replaced it and no difference. The car feels like it misfires at 2500 rpm but runs smooth for the most part. Today I decided to do a compression test on bank 1 and cylinder 1 came in at 85 psi and cylinder 3 at 90 psi. Is it possible I blew a head gasket?
 

·
Æternum
Joined
·
19,971 Posts
Head gasket failure is easy to diagnose.

Is there yogurt in the oil? Does the coolant look and smell contaminated? Does the car consume coolant?

There are a number of reasons for low compression. Head gasket failure is one of them, but so is valve failure (guides, lands) and piston failure (rings, lands, crowns).

The belief that EJ257s frequently burn through headgaskets is misinformation that started from headgasket issues on the NA EJ25 phase II engines. The turbo variants more commonly burn through pistons. Your next step should be a Leakdown test.

Sent from my SM-G960U using Tapatalk
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
No milky oil and no funny coolant smell or consumption of any sort. Also no ticking or tapping coming from engine. And a leak down test is the adding of compressed air in the cylinder and finding where its leaking correct?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
Ok couldn't do compressed air but I did smoke the cylinders. Cylinder 1 came out the exhaust and cylinder 3 came out of cylinder 1. Should I re do cylinder 1 with #3 spark plug removed
 

·
Æternum
Joined
·
19,971 Posts
You should really do a Leakdown test, properly. Be sure the valves are closed and that the pistons are rocked around TDC.

Sent from my SM-G960U using Tapatalk
 

·
Registered
Joined
·
6 Posts
Discussion Starter #8
I came around to finally doing a leak down. Cylinder 1 I's 5% cylinder 3 I's 2-3% and 2 and 4 are at 1%
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
I used 90 psi I did go up tio 100 but same results. For now I bought new plugs then putting everything back together and do a compression test on all cylinders and see my differences
 

·
Æternum
Joined
·
19,971 Posts
Huh, yeah. Interesting that it's losing compression. Typical piston ring and land cracks should also be obvious in a leakdown. I don't suppose you rocked the piston around TDC when you did the test? That's the proper way to perform the leakdown test and helps to determine if it's a ring sealing problem.

Last defining test -- take some clean motor oil, squirt about 20cc into cylinders 1 and 3 (motor warm) and redo the compression test on those cylinders. If you see the compression shoot up, it's a problem with ring seals.
 
1 - 11 of 11 Posts
Top