Questions and Answers

Accord PCV Problem? Q. Hi, I am working on a 1987 Honda Accord for a friend. From what I have read on the internet, there is apparently a problem with the crankcase ventilation system in 1986 to 1989 Accords that causes a blockage and oil to be forced out through cam seals, timing gear covers, valve cover gaskets, etc.

I'm seeing evidence of that. What needs to be replaced/repaired to eliminate this, other than just the PCV valve?

Thanks,
Tom

A. The Positive Crankcase Ventilation (PCV) system is a very basic system that hasn't changed too much over the years. I don't know if the 1986 to 1989 Honda Accords were any more prone to problems than other cars, but I don't think it is the cause of oil being pushed out of the seals and gaskets. The PCV system induces negative pressure in the system so, is anything, it would suck in, not push out.

As you can see in the diagram the major components in the system are the PCV valve and the hoses. If the PCV valve is good and all the hoses are clear and good, the system works. If the system fails, the worst that happens is that there is normal atmospheric pressure in the crankcase.

If there is positive pressure in the crankcase pushing oil out, there is only one place it can come from. The combustion chambers. If the rings are weak and compression is lost past the rings into the crankcase, you will develop positive pressure. The PCV is designed to remove normal blow by but when it gets excessive, it can't handle it and the positive pressure builds.

If you take the oil filler cap off while the engine is running and the PCV disconnected and see smoke come puffing out, you have bad rings and that is the cause of the oil being pushed out.

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