I've been wondering if my car is burning small amounts of coolant. Some mornings, the exhaust has a sweet smell to it rather than just the nasty exhaust smell. The overflow tank is on the low side; however, I did have a leak caused by the hose clamps not being tight enough, so I don't know for certain whether it's just low from that.

I bought a compression test tool and watched a few youtube videos describing how to do it. Every one of those videos said that you should crank the car for a count of 5 revolutions of the motor to get your results. When watching those videos, it was clear from watching the compression gauge that the pressure stopped increasing by the 4th to 5th count.

My car was different though. On mine, I set the gauge so I could watch it while cranking. I had to crank my car 8 to 9 revolutions before the needle on the compression gauge stopped rising. Overall, I think my numbers were okay (newbie perspective at least), but it surprised me that I had to crank so much to get the numbers to top out.

Here were the numbers I got:
Cyl 1: 195 Cyl 2: 188 Cyl 3: 195 Cyl 4: 195

Two questions:
1. Is it normal for my car to take 8-9 revolutions to get those readings?
2. Do those readings look normal for my car? (I have 238k on the engine - think it's original).
Note: I retested cyl 2 just to make sure I got the correct results and it was consistently a little lower but obviously not that much.

Thanks in advance,

Jonathan

 

Excellent results; the lowest is only 4% less than the highest.
I think the most important part about the number of revolutions is to be consistent across the cylinders. I wouldn't worry about the absolute number of revolutions.
Does the car run rough for the first few seconds after a cold start?

 

The car starts / runs okay when cold. However, the idle is not completely smooth - especially noticeable when warm. The steering wheel vibrates (especially with the A/C on), the idle is a little low (often idles around 600 rpm), and when sitting at a stop light, I can feel random jerks/vibrations in my seat / steering wheel from the idle - not certain if that's an engine miss or what causes that (sorry I don't know how to describe it better).

I will add that I removed my throttle body this past weekend to clean it thoroughly and the rubber gasket had turned to plastic and was very hard to remove, so I suspect it was original. That makes me think the head gasket is likely turned to plastic as well. I also cleaned the IAC this past weekend but the idle still wasn't smooth this morning still - still felt those random vibrations in the seat while waiting for a stop light. I'm not certain if my FITV is bad too. See this post: https://www.hondaaccordforum.com/for...uestion-48352/

So is sweet smell from the exhaust / gasket condition of the throttle body a reason to be concerned about the head gasket's condition?

 

You can't detect a HG leak w/ a compression test. There are several methods, but a cold system leak test is pretty definitive. It will allow HG and other leaks to be determined.

Coolant can leak into oil, so check the oil for water contamination.

Coolant in exhaust system is usually easily identified by bright white smoke (steam) as opposed to oil smoke (bluee-gray).

good luck

 

The head gasket is made of steel so it won't turn to plastic.

I'd be more concerned about the exhaust has a sweet smell than the minor idle problems. Do you see any white smoke as TexasHonda described? It may be with a very small head gasket coolant leak that any coolant would burn very quickly so you might not notice it. On my bad head gasket I didn't notice any white smoke but the car did miss for just the first three or four seconds after a cold (overnight) start.

X2 on a leakdown test if you really are losing coolant, there are no more external coolant leaks, and smelling burning coolant at startup.

 

That's good to know-thanks!

White smoke? Typically no (although I can't see what my car does when I first start it). I will say that about 2 weeks ago in the early morning when the weather was about 55-60 degrees (I'm guessing), was a grayish day threatening to rain and was fairly humid I think, my car was putting out a good amount of white exhaust (more than I had seen typically) shortly after starting it when waiting to turn right onto the main road near my apartment. My roommate (whose car was in the shop that day) noticed that the exhuast had a kind of sweet smell to it (he's had a car with a bad head gasket before). Typically on days like that I would see other cars blowing white exhaust as well and I think that I saw one other car doing it a little - though not as much as mine (although mine was probably a colder engine). By the time my car warmed up, it wasn't outputting much of anything visibly.

Sorry - I don't understand this part. Are you suggesting I do a leak down test in addition to the cooling system pressure test? If so, do you know where I can rent an air compressor? I really don't feel like paying $150-$200+ for a decent air compressor when I live in an apartment and don't have need of one on a regular basis . . .

 

I see. I thought it was an everyday occurrence.

If you're not losing coolant - if tightening the hose clamps fixed the problem - then don't worry about a bad head gasket.