I have a G35 sedan,had a compression test done and it came back like so:

1 - 175psi
2 - 175psi
3 - 150psi
4 - 175psi
5 - 150psi
6 - 175psi

I have been told the standard compression is 175psi.

Should I be worried about this? In addition, the oil coming out of the engine each change is very dirty, but is improving over time. I suspect the previous owner did not change the oil too often. It does not appear to burn oil. The O2 sensors need replacing however and is blowing black smoke when revved hard (rich fuel most likely I imagine?).

The car says it has 55,000 miles on the clock but I suspect it is closer to 125,000 miles (or more) upon inspecting the amount of carbon deposit in the intake manifold.. it was caked thick black and took two days to clean up to a reasonable standard. I suspect the clock was replaced/wound back.

How long should I expect the engine to last before requiring a rebuild?

Also, how long do the auto trannies tend to last before they give up or need expensive repairs?

 

*BUMP*

Anyone?

 

I think 150 is within tolerances but you could always check with a master tech at the dealership. If you're not burning oil, I wouldn't worry too much about it. What makes you think the O2 sensors need replacing - you've got a CEL code?

The 5AT can last a good long while if you drain/fill the fluid with S-matic every so often (I would do once per year as it is easy). I think the dealer recommends a drain/fill every year or a full flush every 2 yrs. If the 5AT hasn't experienced deteriorated fluid or overheating, it should be fine.

 

Thanks heaps rcdash.

Yeah got 3 error codes, apparently all linked back to a failing o2 sensor. I'm just waiting for the parts to come in, see how it goes. It is blowing a lot of rich black smoke upon acceleration.

Thanks for the advice on the AT. The fluid appears pretty clean and it hasn't overheated or ever misbehaved (touch wood), so hopefully is in good shape. Just was worried with how many miles it may have done (unknown potentially) as to how long it might last.

 

I think that 160-180 is the tolerance level.


I have 148,500 miles on both my engine and tranny right now(5AT). I should do a compression test to check on that but still runs strong.


Have you called the dealership to see if they have service records for your VIN? Might be a way to check if the clock has been turned back.

I do a drain/fill on my trans fluid every ~15K miles or so. I don't have a tranny dipstick in the early 2003 model. I've had to take it to the dealer to check levels. I need to find a tool to use for that.