Thecrazytrains

Hey everyone, been a while since I've been on here. Couldn't find anything on the forums relating to this issue so sorry if this is a double post...and sorry for the novel..

It started while I was doing an oil change the other day. I changed it after 3,000 before winter, and I'm running synthetic. The oil came out very black, but not burnt. I noticed almost all of my coolant was gone and my engine seemed hotter than normal but the temp sensor on the dash wasn't showing any irregularities.

I had the radiator pressure tested and had a small crack in it. I just replaced that and topped off my oil which is when I noticed there was excessive positive pressure in my crank case. (Coming from the oil fill). My emission light came on and after doing some reading, decided to replace the pcv valve. After replacing, the emissions light went off but the pressure is very much there.

My car is an '06 and has 128,000 miles. I've heard mixed things, but is this normal for older cars or does it seem like there's something else going on?

TexasHonda

All engines produce blowby. To my knowledge, there are no specs on what is acceptable for TSX. I would suspect at idle the crankcase pressure should be subambient (< than atmospheric pressure), but I don't know this to be a fact.

A symptom of excess crankcase pressure is reverse flow from crankcase into PCV air intake. If this is happening excessively under throttle (some always happens), the air intake duct downstream of the PCV air inlet will be coated w/ oil from crankcase vapor.

Some cars (bmw, VW) employ an oil scavenger system to separate oil from crankcase vapor before entering intake.

Why do you suspect your crankcase pressure is too high?

good luck

Thecrazytrains

I just replaced the valve and it wasn't very dirty or stuck. I've done decent amount of work on my car and just recently became noticeably louder and more air coming out of the oil fill cap when I open it than their used to be. The reason I started looking into this is because of those other issues I had recently and I noticed my engine sounded a little different than it used to.

TexasHonda

Suggest checking entire PCV system (both PCV air intake and delivery to intake manifold) for possible blockages or restrictions limiting air flow in PCV hoses.

Also check vacuum level for engine. It should be 19-21 in-hg at a fast idle. Low vacuum could indicate an intake air leak or possibly engine problems.

Sound change could be due to exhaust leaks.

good luck