1998 V70 T5 - oil leak/smoke on acceleration/deceleration

Seaway · Post by **Seaway** » 10 Feb 2015, 06:09

I have a T5 Manual with 186,000 miles that has a small (no puddle on the ground overnight, just quarter-sized spot) oil leak and smoke when boosting and then coming off the throttle after boosting. I also occasionally get a puff when making a hard turn as though pooled oil is being sloshed and then burned. I have had to add a quart and a half of oil in roughly 1500 miles. If I drive only in town and stay out of the boost, I don't get the smoke. My inclination is that it is turbo related.

The PCV was replaced at about 178,000 miles and the turbo has about 105,000 miles on it (according to the previous owner). With the exception of the occasional smoke, the car runs extremely well with great power. I have a Snabb intake with a brand new PTC, new silicone intercooler hoses, and no engine codes. There is not a lot of oil at the lower intercooler connection, the hose was wet with oil, but no pool of oil, nothing dripped or ran out when I removed the hose.

I have gotten under the car and the oil appears to be coming from the dipstick/PCV area on the front side of the engine. I have no smoke from the dipstick, and the "glove test" shows vacuum at the dipstick as well. There are no funky fumes or anything to suggest the PCV system is clogged other than the smoke.

I am wondering if the smoke is a result of bad seals in the turbo and the leak is at the PCV or dipstick tube?

I get no smoke at start up, no smoke at idle, no smoke on a downhill coast in gear (with the boost gauge showing approx 25 inches of vacuum), so I am assuming the smoke is not a result of valve seals.

Can anyone lend some direction, or is the smart thing to do replace the PCV system and trouble shoot from there?

Post by **Ozark Lee** » 10 Feb 2015, 07:13

It could be oil seals in the turbo but the turbo seals don't typically result in any oil on the ground. A light film of oil in the intercooler lines is pretty typical. Turbo oil seal leaks on the hot side of the turbo tend to cause the most smoke. How is the end play on the impeller? If there is significant slop it might be time for a turbo rebuild and the oil seals get replaced as a part of that.

The glove test seems to indicate that the PCV is still OK.

Where do the drips under the car appear? In the turbo area or more toward the front of the engine? The oil cooler lines are known leakers and they can be tough to pinpoint the source from since when they leak it tends to distribute oil everywhere. Drips from back around the turbo are often the oil return line gasket which is another known problem area.

...Lee

Seaway · Post by **Seaway** » 10 Feb 2015, 07:22

Ozark Lee wrote:It could be oil seals in the turbo but the turbo seals don't typically result in any oil on the ground. A light film of oil in the intercooler lines is pretty typical. Turbo oil seal leaks on the hot side of the turbo tend to cause the most smoke. How is the end play on the impeller? If there is significant slop it might be time for a turbo rebuild and the oil seals get replaced as a part of that.

The glove test seems to indicate that the PCV is still OK.

Where do the drips under the car appear? In the turbo area or more toward the front of the engine? The oil cooler lines are known leakers and they can be tough to pinpoint the source from since when they leak it tends to distribute oil everywhere. Drips from back around the turbo are often the oil return line gasket which is another known problem area.

...Lee

I should have been more specific... the oil shows up on the front of the engine and runs down to the oil pan and manifests itself as small drips on the rear of the pan. The pan has a sheen of fresh oil on it after a couple days of driving, but never more than a very small spot on the ground.

I am inclined to think the leak and the smoke are unrelated problems. Though there is oil at the oil return line at the turbo (the line with the two small screws on the bottom of the turbo, right?) so that gasket likely needs to be replaced.

The turbo has some play in the shaft, but I am not sure what "normal" is. I know that on my turbo diesel engine in my boat, there is really no play at all in any direction on a Garrett turbo. My Volvo turbo certainly has more play than that.

How hard is a turbo rebuild? Something that can be done in a day? I have removed and reinstalled the turbo on my boat, so I am confident with that part of the procedure, but I have never opened one up.

Post by **Ozark Lee** » 10 Feb 2015, 07:34

Rebuilding the turbo is fairly easy but there are a couple of snap rings that are a real b*tch. I had to stop part way through to go buy a real heavy duty set of snap ring pliers. If you want it to be perfectly balanced then you need to send it out to a turbo shop to get it done but if you are careful when you scribe the shaft and the impeller it is typically close enough

I don't really know what the service limits are. I had one that had, guestimating with the end of my finger, about 0.015 of end play and it was pretty well shot. If you do rebuild it get a genuine Mitsubishi kit and don't disassemble it near something like a computer monitor since one of the snap rings tends to sail when it is removed and it has some force behind it.

Here are some links that are real helpful:

http://www.volvoforums.org.uk/showthread.php?t=48611

...Lee

Seaway · Post by **Seaway** » 10 Feb 2015, 07:42

I am almost certain that mine has more play than what you are describing. It also almost seems to "seat" itself at times and not smoke, and then begin to smoke again after romping on the throttle. I imagine sending it off to be rebuilt is pricey judging from what I paid for my boat's turbo rebuild. I will look up the rebuild process and see if it sounds like something I am comfortable with. I am also going to look at the oil cooler lines and see if that could be the source of my mess under the car. I am going to have it up on ramps tonight so hopefully I will be able to see what is going on.

Thanks for your help.

Post by **Ozark Lee** » 10 Feb 2015, 07:58

One other thing.

If you do rebuild I would also get a blow off valve rebuild kit which gets glossed over on the writeup and the videos. At this age and typical mileage most of our BOVs have leaky diaphragms.

...Lee

Seaway · Post by **Seaway** » 10 Feb 2015, 08:09

Ozark Lee wrote:One other thing.

If you do rebuild I would also get a blow off valve rebuild kit which gets glossed over on the writeup and the videos. At this age and typical mileage most of our BOVs have leaky diaphragms.

...Lee

I actually thought about that. I am running about 16 psi of boost, so it couldn't hurt to have a new diaphragm. I just watched the rebuild videos, but my fear lies in the balancing of the turbo. How is that accomplished? In the video, the guy simply puts the new compressor wheel and turbine wheel on, buttons everything up and calls it good.

Post by **erikv11** » 10 Feb 2015, 08:18

A turbo rebuild is $350 plus shipping at http://gpopshop.com/services/rebuilding/ which is a highly respected vendor.

Seaway · Post by **Seaway** » 10 Feb 2015, 08:32

That is the same price I can get it rebuilt locally without having to ship it off.

Post by **erikv11** » 10 Feb 2015, 08:40

Yeah, it seems to be the typical cost.