Hey all, new to the site and I'm having some trouble pinpointing an oil leak. I pulled a 2001 S40 out of a field and got it running for a neighbor. Replaced head gasket, heater core, t-stat and temp sensor. Worked all of the bugs out except two...cooling fan stays on (I figure the fix is a new fan) and I've got a massive oil leak on driver's backside of the motor (right under cam sensor area)...that's the one I need help with 'cause I can't find the source! I gotta be missing something.

Cam sensor to block and upper cylinder head to lower head is dry (white arrows in pic). I cleaned the area w/parts cleaner and ran the car in the driveway for about 30 min and no leak, but as soon as I return from a 5 min drive, the passenger side drive shaft, coolant crossover, and the corner of the exposed head gasket are dripping w/fresh oil (black arrows in pic). Bottom of all parts from turbo to halfway across drive shaft is wet. I kind of think something could be spraying oil...maybe that passenger side drive shaft? Bottom of all parts from turbo to halfway across drive shaft is wet.

I pulled the upper heat shield and took the pics...please let me know if I'm overlooking a known issue or something more obvious.

 

Hard to tell from the pictures the oil always find its way to go places where the wind takes it far away from the leak.This case I'm thinking the turbo oil return which known for fault.Its an O-ring on the end of the pipe coming back to the engine.You should be able to smell the difference between engine oil and axle lubricant.The fan always running issue usually points at a faulty MAF sensor.Try to clean it.

 

Thanks for the advice, I'll take a look at that o-ring.

As for the MAF sensor, I am geting a CEL for low MAF input. I have cleaned it, but it continues to pop. That's the last thing I would have thought would cause the fan to stay on. Again, I'll check and report back.

 

Oil leak is definitely the oil return o-ring and or gasket at top of rigid hose. Not a huge job. Note that the hose itself is also prone to corrosion. You may want tickets replace it too.

 

Sorry for the time between posts. Weather in my neck of the woods hasn't been cooperating. It's finally warm enough to slide under the car and inspect. I pulled the drain tube and sure enough...the seal was in pieces.

 

After reassembly, I found more oil. Ran my finger under the exhaust cam rear seal, and it's REALLY wet with fresh oil. JACKPOT! Buying a new rear cam seal tonight.

Quick question though...should the cam sensor cover be RTV'd or installed dry?

 

Make sure it is the seal actually.This model is notorious about a leak on the Ex cam gear itself.There is an o-ring on the adjustable part which does leak on almost every one of them.I was told that this is nothing more but a plug which seals a hole on the part which was created during manufacturing and can be just glued/sealed around.

 

Mine was installed dry. The cam seal worked well enough. You might get some strange behavior if the cam sensor cover fills with oil.

The CVVT gear is known weak point for oil leaks. Watch for oil being slung onto the timing belt.

The cooling fan running continuously can also be a bad coolant temp sensor. I had a problem with an brand new aftermarket CTS causing the fan to run after the car was shut off. A genuine Volvo CTS fixed it.

 

Note for the OP: the VVT gear (which I think is what is being referred to above) is on the front side of the engine, not the rear where the cam sensor is located.

 

Only the exhaust cam has the VVT which is on the rear of the engine./Not sure what you are trying to say.

 

I tried to address the cam sensor cover first, then the CVVT gear so as not to confuse the conversation. Did I fail?

 

Sorry it took so long to reply.

I had previously re-ringed the VVT to fix that hemorrhage point. This one is coming from the rear of the Exhaust cam and definitely coming from the rear cam cover. I had to pull the dang thing off 3 times to stop the leak.

1st attempt was RTV and reinstall. Leaked from bottom of cover at the bolt (from a small casting valley built into the cap) and down the cam sensor.
2nd attempt was new rear cam seal, RTV, and reinstall. Leaked from top bolt (from same casting valley on the top side of the cap)
3rd attempt was RTV the snot out of the thing. Leak gone Told buddy to sell it before something else breaks!

 

GerBeGurGya, thanks for the tip on the MAF sensor...that was keeping the RadFan from shutting off. Thank you all. Three VERY useful tips that solved three biggies on this one.