Need help diagnosing oil leak [1997 Volvo 850 GLT]

Post by **1997volvo850** » 02 Jun 2016, 20:17

There are a lot of threads discussing various oil leaks but I did not find a repair manual for diagnosing oil leaks. I may try to put one together when I'm done.

I've been busy with life and didn't realize that my PCV/PTC became clogged and has resulted in a major oil leak. I'm not sure I'll be able to fix this so I'm coming here to learn from members with first hand experience with the 850 and oil leaks.

I have not ripped my car apart yet since I can't see where the oil is coming from.

A week or so ago I started observing a major loss of oil. I did not realize my PCV/PTC system was causing pressure at the time but I now know that my 850 will keep a glove slightly inflated with the dipstick out. So I have a problem with PTC or PCV.

My oil mileage was quickly approaching my gas mileage at about 50 miles per gallon of oil. I needed to check the oil and fill every 25 miles.

After realizing the breather system was not working properly I started leaving the dipstick out to allow pressure to escape from the engine. After doing this the oil loss declined drastically to less than a quart every 50 miles.

I should also point out a significant amount of smoke coming from oil burning on top of the exhaust system. I'm hoping this might indicate the source of the leak or possibly eliminate other sources.

I understand excessive pressure will destroy the cam seals, rear main seal, and possible damage seals in the turbo area. Are there other parts that the pressure will destroy? I'm surprised the designers did not build in a relief valve to avoid such catastrophic damage to the engine - much like a water heater has a relief valve to sop it from exploding.

The first question for the experts here is which seal is excessive pressure in the engine likely to destroy first?

The last piece of the puzzle is for those guru's here who are able to touch a car and diagnose what's wrong with it. I'll go one better and provide a picture of where oil is dropping to the ground. I'm hoping someone will be able to help diagnose this based on the location of the oil dropping to the ground and the excessive oil being deposited on the exhaust system. My suspicions are the turbo seals but the cam seals and rear main seals are all in the same general area. This is where you experts make a picture worth a thousand words...

: She leaks more than I do these days.

I've tried to look down into the engine to see where the oil is coming from but there is too much stuff in the way. The oil leaks while the engine is running but I'm hesitant to get under there while the engine is running. For the most part it seems to be dropping in the vacinity under the turbo/rear main seal.

Let's see if this goes anywhere before I continue.

Post by **MadeInJapan** » 02 Jun 2016, 21:11

You really need to get that up on ramps and do a "de-greasing" or "de-oiling" in your case and see where it's coming from...it's not a job I want to do laying on the ground under the car.

Post by **Clemens** » 02 Jun 2016, 23:38

Less than a quart per 50 miles? Wow, that is alot. My wifes 850 needs a quart per 500 miles and that is actually bad. Like Made in Japan said: try cleaning up that motor as good as you can. Then you should see it squirting out very soon again.

Post by **tryingbe** » 02 Jun 2016, 23:53

Could be the oil return tube seal on the pan.

beigg · Post by **beigg** » 03 Jun 2016, 07:18

broken flame trap canister, especially if it's non-oem brand.

Post by **MadeInJapan** » 03 Jun 2016, 08:12

Could be but it could also be rear cam seal (likely culprit) as well as pretty much anywhere- possibly the turbo return line- it's seal goes bad on either end and oil comes out of it like sieve. Good news is, it's not hard to replace and it's an instant fix and you'll be relieved it's not a rear main seal.... but again, until it's cleaned up and up where you can see it from below, you're pretty much guessing...from above, you can however see if it's any of the rear cam seals..my bet would be on the exhaust cam if that's where the leak is- it's the one under the throttle position sensor (TPS).

Post by **1997volvo850** » 03 Jun 2016, 08:36

If it's the rear main seal would this result in significant oil deposits on the exhaust system...of course I could have multiple damaged seals...

was hoping the location of the dripping oil might narrow the possibilities or eliminate some...

the rear main seal is the expensive one...

Post by **MadeInJapan** » 04 Jun 2016, 07:18

1997volvo850 wrote:the rear main seal is the expensive one...

Yes, but after de-greasing, and running the engine it will be obvious if that's it or not...there's a little weap hole whee the engine and transmissions are joined up and you'll see oil trickling out of it.

Post by **1997volvo850** » 04 Jun 2016, 21:28

MadeInJapan,

Thanks for helping. I stopped by to see Dave B. in Ithaca and he replaced my rear exhaust cam seal. This appears to have done the trick.

My car is pretty yucky after all of the atomized/burned oil flying around. What do folksrecommend for cleaning the engine compartment and the area under the engine? Should I open the hood and spray engine cleaner degreaser all over and rinse it off - or will this 'end' my car.

I suspect spraying from underneath the car would be ok. I would like to get rid of the current mess so it's easier to track the next oil leak. Point me in the right direction...

I still have pressure issues so I will takes those questions to the PCV/PCT threads or create a new thread. There are quite a few things I'd like to discuss.

Post by **MadeInJapan** » 04 Jun 2016, 23:42

I wouldn't spray it all over, but strategically spray...cover the essentials (especially electrical)! Washing would follow the same guidelines.
I'm glad the main leak was the exhaust cam seal instead of something more major!