Hey guys, still maintaining our great Volvo S40 we got new in '01. Just past 200,000 miles. Last May car was running rough. Went to Tire Kingdom and they cleaned my injectors, this pretty much settled the engine down. After 2 cat changeouts, I've been experiencing the famous P0015 code. Dealer first changed out cam reset valve, then when it came on again , they changed my oil. Well it still came back and they were doing more tests, possibly determining that coolant is leaking into a cylinder head. Well car is running a little rough again. I tried the Techron, and it worked fine for almost the first tankful, now on my second tankful and still running a little rough, not as bad when I put the A/C on. Could it be the IAC valve? Thanks for any ideas .

 

Could be a defective VVT gear. You'll want to check the condition of your PCV (breather) system before replacing though. If the oil trap is full of gunk it may have gummed up the gear.

There are a few tricks out there to measure whether or not you are experiencing PCV issues. If you don't take care of this, you may blow a seal (like I did), clog up the solenoid and vvt gear, as well as gunk up your engine.

Replacing the VVT gear is basically a timing belt job + the purchase of a new vvt gear ($180) so you might as well do both at the same time if this turns out to be root cause.

Let me know if you are interested in finding out more - I know of guides out there for both the PCV and the VVT gear replacement.

 

Thanks Pierre, I did have a VVT gear change with my belt change (timing) about 4 years ago or 70,000 miles ago. This was after the 105,000 timing belt change because some oil leaks developed down there. I'm now at 204,000. I did talk about that VVT gear to the service people at Volvo. Because we usually bring our car to the dealer for oil changes and repairs, sludge is not a factor in this case. So I didn't leave it over to go through all the tests, rough idling sometimes, P0015 sometimes. I don't know if they checked out the PVC thoroughly. I don't even know what that is yet. So today it drove home quiet, with the A/C on!

 

Hmmm, your mileage is such that you should probably ask dealer to check the PCV if they have not already. I wonder if maybe your cam sensor is going wonky. That sensor is bolted onto the rear of the exhaust cam and is removed by unscrewing 2 10mm bolts. The lower one is a bit difficult to get to but overall the job is a quick one.

 

Hi again. Yes the dealer did check the PCV, and like I said, they wanted to keep it and test it further to see if maybe coolant was leaking into cylinder head as they have seen that before. But what's the point? I'm not going to put any more thousands into my S40. I'm just gonna Techron it with the a/c going. It seems to idle pretty well at 800 RPM'S.

 

Yeah, it gets harder and harder to justify as the mileage mounts, I hear you. I hope you get it sorted (cheaply). Who knows, you might get another 100K miles out of here without any major cash outlays.

 

Thanks Pierre!