98 v70 exhaust fumes in car, wastegate shaft

paul c · Post by **paul c** » 04 Mar 2015, 13:57

i don't post much but i need a hand. my 98 v70 glt with 230k gets exhaust fumes through the heater vents with it on and fresh air mode when at idle. my cat back exhaust was compromised at the muffler so i replaced that and with it off i used a smoke machine to test the cat forward. i was getting a small stream at the front pipe to turbo flange and also a lot out of the wastegate shaft. i found the shaft seemd to have excessive play in it. i picked up another turbo with half the miles on it for a good price and noticed the wastegate shaft also had play. the seller deals in volvos and parts. he checked couple of others and said they also had play. there isn't a gasket between the front pipe and turbo so i tried some copper rtv, used a thin bead, reassembled and let it sit over night. seemed better before i drove it then it came back. my question is about the wastgate shaft, do they have play in them or are they suppose to be pretty tight? i'm bringing the smoke machine home again tomorrow to check again. thanks in advance.

Post by **rspi** » 04 Mar 2015, 14:54

People usually smoke the intake system, including the turbo intake piping, not so much the exhaust flange and exhaust. Yes the wastegate arm shaft does have decent play when cold, heat that thing up to 1,800 degrees F and hopefully it will still be loose enough for the actuator to open and close it.

The seal at the front of the window/engine bay cowling should seal off most engine fumes.

huzzsaba · Post by **huzzsaba** » 04 Mar 2015, 15:03

rspi wrote: The seal at the front of the window/engine bay cowling should seal off most engine fumes.

+1. I had that seal missing on a 850 back in the days, and definitely smell got it through the vents. otherwise, you may have a exhaust leak.

paul c · Post by **paul c** » 04 Mar 2015, 15:15

The seal is there on the cowl, my main question was that shaft. I will be able to smoke test it on friday again. With the heat off or on recirculation there is nothing. I did replace the air pump check valve and it seemed to start after that. Didn't see any leaks near it and might just be coincidence.

Post by **JDS60R** » 04 Mar 2015, 15:58

Hi Paul.

The waste gate shaft hole does wear and will expand when heated (gets worse). Normally that is not enough to notice. The common failures I have seen are the flex section of the pipe leaking or the seal to the hood removed or damaged. I would run the car from cold with the turbo shield off and feel where the leak is coming from. It gets hot fast so no direct touching of the metal.

Check for cracks where the intake air goes in for the HVAC. It should be pulling outside air only if the seals are in place and working. If the water drain pipes have been removed it can sneak up the tube as well.

paul c · Post by **paul c** » 04 Mar 2015, 17:17

I'm going to smoke the tailpipe again and look for smoke with the heat shield off. I just checked those tubes and they are intact. I worked at a volvo dealer for ten years and never saw this before. Can't really see fumes. I just tried adjusting that seal a bit on the cowl cover. Thanks again and I'll post if I find something.

Post by **scot850** » 04 Mar 2015, 19:05

Other suggestions to check. Are the fumes being draw in from the rear of the car? Check the seals around the tailgate. Also make sure you have the trim on the end of the exhaust. I had that missing on one Volvo and it allowed some fumes to gather under the back of the car.

Are you 100% sure it is exhaust fumes and not either the evaporator for the A/C leaking or the heater core? I guess you said that when you have it on re-cycling you don't get it so it would rule that out. Check also that all the bungs and seals are in place on the firewall, and the seal is good around the steering shaft.

One last thing, the exhaust manifolds on turbo engines can crack and leak, but normally you will hear that. Check both engine warm and cold for this one.

Neil.

paul c · Post by **paul c** » 04 Mar 2015, 19:58

Not from the rear, new cat back exhaust also. No abnormal exhaust noise. I did pull up on that seal on the cowl cover in one spot where there didn't appear to be a witness mark on the hood and it almost seemed to help. I am going to remove it in the morning, add some butyl tape to the mounting side to build it up. I'll smoke yest the exhaust again and then see how it is . Thanks for all of the suggestions.

Post by **gmh** » 04 Mar 2015, 21:43

The other issues aside, it might be worth a look under the spark plug cover. Oil from pcv blockage or a leaky filler gasket collects and when the engine heats up the fumes are sucked into the fresh air intake. Usually not noticeable except at idle. Just a thought.

paul c · Post by **paul c** » 05 Mar 2015, 00:57

you can pretty much tell its exhaust coming in and not burning oil. i had a small oil leak last fall and that odor was coming in then, since repaired. i set up a light under the hood and closed it, since it's dark out i should be able to see light between the hood and the cowl seal if it's leaking. all dark, if i picked up on the back of the hood then you could see light so that isn't the issue.