1998 C70 - Weird oil reading/Turbo spitting oil

andreborges · Post by **andreborges** » 18 Jan 2015, 19:47

Hello, dear forum members.

Recently I've drove the c70s 1st long trip. It turned out quite fine, stable as a monk's meditation. I reached the end of the journey smiling ear to ear. Drove around town, slept the night and returned to my city. Next day I decided to check the fluids and the turbo leakage (old problem, I have not been able to diagnose precisely by myself...). All apparently normal at the turbo department, with only a small amount of oil sipping thru the case. After turning on the car prematurely, by mistake, I decided to check the oil whilst it was still cold and then "there was blood": VERY low reading from the dipstick. Needn't say I turned the car off immediately. After a while, again, deciding to check the level, the oil was back, quite close to the middle...

How could this happen?

Also, on the subject of the turbo, are there any lines known to creep oil to the outer turbo housing?

Any help will be enormously appreciated!
André

Post by **rspi** » 19 Jan 2015, 02:49

Hi André, if you check the oil with the motor running you will get a bad reading because oil is being cycled through it. You should always turn the engine off and let it sit for at least 5 minutes before checking the level.

Don't really understand your turbo question.

andreborges · Post by **andreborges** » 19 Jan 2015, 06:43

Thanks for the reply, rspi, you've been always helpful. I was truly scared, as I wouldn't think oil reading could change so much (much though I already knew you should not measure with your car running).

I believe I've been unclear about the turbo. There has been some oil leakage to the outer housing. Are there any known leaking lines in these cars or any gasket I should be worried about?

Post by **Ozark Lee** » 19 Jan 2015, 07:33

The oil return line gasket from the turbo is a known weakness. I think we have a tutorial on changing the gasket and the O ring in the repair database.

That said, what often looks like a turbo oil leak really isn't the turbo at all. Leaks from above the turbo, usually the oil filler cap gasket or even camshaft seal leaks make there way to the turbo and the droplets form on the bottom of the cold side housing.

Have you checked the condition of the PCV (Positive Crankcase Ventilation) system? The quick and dirty way to test the PCV is to remove the dipstick while the car is idling and look for vapors puffing out of the dipstick tube. A small balloon or a rubber glove over the end of the dipstick will also tell you if the system needs to be serviced. If you put a balloon over the dipstick tube it should not inflate. If it does then you need to deal with the PCV. The root cause of most Volvo 5 cylinder oil leaks can be traced back to a clogged PCV system.

...Lee

andreborges · Post by **andreborges** » 19 Jan 2015, 09:00

Thanks very much, Lee. Being an avid reader of the forum, the PCV was the first replacement I performed when I bought the Coupe!

Now it only spouts a very thin and transparent amount of smoke upon acceleration, which vanishes the second after.

The oil tends to accumulate in the "belly" of the centre housing (the turbo, per se), Ozark, I could never find where it came from!

Post by **misha** » 19 Jan 2015, 15:29

rspi wrote:...You should always turn the engine off and let it sit for at least 5 minutes before checking the level...

This is usual recommendation in all user's manual but in practice,it is a little different.The best time to check oil level is when engine is cold,after it sit overnight and always on level surface.

You can check oil level,like rspi advised,3-5 minutes after the engine is switched off,but that would be approx.level.

True oil level can be read only when the car sits overnight,when engine is cold.

Differences could be around 200-300ml.

andreborges · Post by **andreborges** » 19 Jan 2015, 21:04

Indeed, misha! I sat it overnight and double-checked the level, which was indeed in the half section of the 1,5l zone (middle of the "acceptable" part of the dipstick). I added half a litre to see it rise to the top of said section.

I never changed the oil lines in this car, and whilst I never heard of them failing without notice, could it be possible to have such a leak it could damage my engine? Is the oil return line the usual suspect when oil is accumulating in the "belly" of the snail?

Thanks very much, guys!