I have a 2005 with 133K on it. It was running rough and misfiring on multiple cylinders. I had a leak down test done and they indicated that the valves were likely bent and said the car had probably been over revved at some point. They indicated all cylinders compression were over 200 with the exception of the only cylinder not misfiring and that was said to be at 150ish. After they did valve adjustment to set to max spec misfires went away, the car is running much more smoothly and it feels great. However I am contemplating what to do the low compression on the one cylinder, especially with the clutch feeling stiff and have 100K on it. They did not reperform the leak down/compression test after the valve adjustment.

I took it to a dealership a few weeks after it continuing to run well and asked for a leak down test. They told me that there was a slim to none chance the valves were bent due to the way it was running and the way the valves sounded. They also indicated they could tell on the dealership computer that the car had never been over revved, or at least not since the last time the car was at a Honda dealership. They also did not perform the leak down test requested but did say the compression test was "all good". When I asked for the compression numbers before leaving, they called the tech and was told 170 on all cylinders.

I can imagine that they did not recall the exact numbers across all cylinders, and that is fine as long as there we no significant variance across cylinders. However, the 170 number seems surprising low and consistent across all cylinders and is yet another inconsistency with the previous leak down test prior to the valve job. There is a part of me wondering if they did the test at all.

I know that 170 is within spec per the manual (135 - 228 with no more than 28 psi variance between cylinders), but what does that tell me about the engine if 170 is true? This number seems very low compared to most well maintained S2K's.

Should I have this test done again and this time be present to see the gauge? Is a leak down test appropriate if all cylinders are at or about 170? Wouldn't this still indicate a leak of some sort? (BTW no noticeable smoke from the tailpipe.)

All thoughts and guidance greatly appreciated.

 

I'd have the compression and leakdown tests redone. Get the exact numbers. It doesn't have to be the dealer — any good mechanic should be able to do these, under the proper conditions.

BTW... is the car burning oil? What is the miles/quart of oil needed?

Thanks!

 

I have had the car for 10 years and the oil always reduces between changes pretty significantly even after the leaks were resolved. There is no noticeable smoke from the tailpipe. I have always read that some S2K's just eat oil and I think I have one of those. Just guessing miles per quart is probably 3000+ per quart.

Any thoughts on what 170psi would mean given the typical range is over 200?

 

I'd get another compression test and note the exact numbers.

One quart per 3000 miles within factory limits. It is not burning oil.

 

It seems like shops will give you extremely speculative or sometimes disingenuous information when doing compression and leakdown testing.

Just make sure you know enough about the testing to ask pointed questions or give pointed information.

You're paying for answers. Not a test. Right?

Would you benefit from an explanation of compression and leakdown testing? Or do you feel you already have a grasp on it?

Sounds as if the car is running fine now with no CEL? And what are you trying to ascertain at this point?

 

Its in English. Dude wants to know if he should worry about the low compression number that became low compression numbers. They're consistent, but that's also the typical number for most Hondas. Could have been a non optimal test or it could just be them saying stuff to get him out of their hair.

OP you want advice, if it's running fine and not burning oil, you're probably ok. If you want to be sure pay for another compression test if you want peace of mind.

The next option is to get comfortable DIY'ing.

 

Like the suggestion above, if you're comfortable doing basic trouble-shooting, you can do the compression test yourself. I had 0 experience wrenching on my car when I DIY'd this right after getting my S2K.

A tester on Amazon is ~$30 and it's a dead simple tool to use.

This way you can SEE the results yourself in real-time and can check and re-check as many times as you feel necessary. It sounds like you would be more confident in the results this way, and it's bound to be cheaper and easier than taking it to a shop.

The smart folks here can then interpret whatever #s you get, and you can decide on next steps if the #s are wacky.

 

Compression testing is highly dependent on consistency from the person doing the test. If the testing method is consistent, then you're mostly looking for consistent results. 170 on all cylinders is totally fine. Some testers read high, some read low.

For a valve adjustment to cure a misfire, the valves must have been massively out of spec to begin with. Did the shop comment on how tight the valves were?

Why on Earth did they speculate about bent valves? And then not provide any evidence for/against that?

A loose spark plug can cause a bad misfire. Did they comment on any of them being loose?

Leakdown testing will give you more info than a compression test. It will tell you where the air is escaping to.

But like others are saying. If the car runs fine and there's no misfire CEL, a leakdown may not be worth getting.

Or it is worth getting, depending on what info you're after...

 

It is near impossible to over-rev a 2004-2009 S2000. For many reasons.

 

Shops suck. Dealers suck. DIY or trusted mechanic that is actually competent and knows these cars.

I'm skeptical dealer even bothered actually performing compression test. My guess, it runs fine, so they made up numbers they thought sounded good. Not realizing what normal compression is for these engines.

While 170 is within spec, who would say everythings fine if they were that low. We're talking about the same people that wanna replace your brakes when pads are down to 60%.

The guys that speculated bent valves don't know what they're talking about. Or just trying to upsell major service that would end up making engine worse (rebuilt head by some Billy Bob).