Oil odor in car when idling, oil found at bottom of intake pipe to throttle body (RIP)

[timetobakethedonuts]

The PO of my 1998 S70T5 took my car to "level 0" and in the process did the reverse intake with a fancy charcoal air cleaner. It/s all very impressive to look at, but I just wanted the car because it is low miles (72k now), and the seats - oh the seats. I was not happy with my 2005 V70 seats in comparison. Over the years I came to accept my V70 seats and this car sat.

FF to today, and I need this car to get me through the winter, as the V70 was totaled by an exploded tractor trailer truck tire.

As I drove the car, a familiar symptom revealed itself from when I last drive it regularly. When I come to a stop, there is an oil odor in the car. Goes away when moving.

I am replacing the lower radiator hose, which the PO absolutely should have done when he replaced all the vacuum lines and put in all this fancy intake stuff. The hose it the original and is weeping at the radiator connection. I removed most of the intake piping so I can get to the hose and rear connection/clamp.

When I loosened the clamp of a rubber elbow that connects the intake piping from the throttle body to what I am guessing is the bottom of the intercooler (? - the unit that sits most forward in the radiator stack), I found oil beginning to weep out. I retightened and I instead broke the connection at the other end of the elbow, that connects to the pipe that goes up and to the throttle body - no oil there but film can be seen at the bend of the elbow which is near the low point. Running my finger over the inside of the pipe that I removed, I feel/see no oily residue.

Any suggestions on what this oil indicates? I am tempted to feel this is not normal, but I don't have a good understanding of PCV. The odor of oil is kind of annoying too, but my main concern is health of the engine.

Thanks in advance,
Don

[Krons]

I’d take the oil cap off and do the glove test to make sure the engine is pulling vacuum. If the PCV is shot and the crankcase is pressurized that could be the root of your smell. Easy to rule that out.

[timetobakethedonuts]

I’d take the oil cap off and do the glove test to make sure the engine is pulling vacuum. If the PCV is shot and the crankcase is pressurized that could be the root of your smell. Easy to rule that out.

Thank you for this suggestion - I had thought of doing this to rule out a clogged PCV - and the possibility the odor might be related. The PO appears to have done that service at 55k miles, and I am at 72K so I was not expecting it to be an issue. But I need to check it.

[timetobakethedonuts]

I apologize for not getting back to this sooner - here is an update.

I did the glove test with a latex glove, and found that the glove partially inflates with a warm engine - it sits sideways but will not stand up or on an angle. So there is positive pressure. There are no oil leaks visible on this engine - YET. I don't want to risk seals being blown.
I found that the oil vapor odor is only in the car when slowing to a stop, if the AC/heater fan is running (no big surprise). Wherever the intake is for the blower, it is sucking in a strong odor of oil vapor from the engine compartment, though I don't know where it is coming from. Could it be blown back out the air intake?

I am about to do a full timing belt/water pump/pulley replacement, but I have to expedite figuring out what is going on with the PCV. I will post separately about this.

[scot850]

The air intake to the cabin is on the RHS under the windshield wiper cover. What you may be smelling is not engine oil but a failed AC evaporator which is allowing compressor oil to get sucked into the cabin along with the fresh air.

Neil.

[454cid]

I could smell exhaust in my car while stopped and very low speeds when it was running rich due to a bad 02 sensor.

[timetobakethedonuts]

Thank you for the replies. I believe I solved the issue as a target of opportunity, while doing my timing belt R&R. I apologize again for not monitoring this post in a timely manner. I was buying a car to replace my daily driver, and doing the timing belt service.

The #1 spark plug was only finger tight, and I believe its rubber seal was not fully seated (as might be expected with a loose plug). I went to remove the plugs (to reduce compression resistance), and was (quite) surprised when no torque was required on this one. The other plugs were all normal, and all five appeared to be equal in wear/appearance. The previous owner had installed new plugs, and I never had any cause to remove them.

The problem appears to have gone away, in a half hour test. Now I don't need to turn off the HVAC when coming to a stop, making the driving experience even more enjoyable. Really enjoying driving this old brick. Solid and tight, and the seats - oh the seats!

Don

[scot850]

Thanks for getting back to us, We can now breathe a sigh of relief!

Funny thing, I worked on a friends 850 about a year ago and it was the same. One of the plugs was not tight.

Neil.

[timetobakethedonuts]

Neil - I detect a slight pun in your reply - ha ha. Interesting. I would have never thought "hey, I might have a loose plug." On the other hand, logic might say any joint should be considered, and it would be an eligible source.

[scot850]

Neil