I have a strange issue that just popped up on my 2005 PT Cruiser GT. I've had the oil pressure sending unit replaced four times in the past six months because it starts leaking. I've read several places that these fail, especially when you use NAPA parts (my mechanic won't use anyone else, unfortunately). After replacing it last week it started leaking the day after and my oil light came on. It's only on at idle, if I get above 1k RPM it goes away, but comes back when the clutch is depressed.

I took it back to my mechanic (who's getting frustrated with me and my car at this point) and he put a mechanical gauge on it. At idle it has about 90PSI of oil pressure, at 3,000 RPM it buried his gauge at 120PSI. The only thing he can think of that's failing is the oil pressure relief valve in the oil pump. This costs an arm and a leg to replace because you have to remove so many things.

Have you guys ever heard of this failing? I am under the understanding that these relief valves are a spring and a ball, if they fail they just stop working and you get low oil pressure, not high?

Any input would be appreciated. I have the money to fix it, but if I fix it I'm going to just keep the car (Which isn't a bad thing, unless you're my wife) but I'd rather not spend $1,000 if I don't need to.