SaabCentral Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
26 Posts
Discussion Starter · #1 ·
hi -

my 207,000 mile 96 aero has suddenly just started losing oil - it never had previously between changes.. I've changed the cam cover seal, checked the headbolts and cleaned up around that area but haven't noticed any large leak there since.

what's worrying is on boost i can smell oil in the car - if this was the turbo oil seals going i wouldn't smell anything would i as the oil would be going out of the exhaust?

with careful driving not using the turbo there is no smell..

thanks

adrian
 

·
Registered
Joined
·
1,025 Posts
Did you try the blow turbo smoke test? With the engine warmed up, open the drivers door, or have someone stand at the back to watch the exhaust for blue/oily smelling smoke. With the engine running, give it some revs to about 3k rpm, and let go, if it blows smoke out the exhaust, then the turbo has had it. Mine used to smoke slightly at idle when sitting at traffic lights. You could just about see the blue smoke from the back when I loked in the rear view mirror.

I got a hybrid t25 made up from Universal Turbo's in Hants I think it was. Cost 565 UKP delivered. They want you to post your old turbo to them when it gets channged tho, they charge a surcharge on top of the new one till they get it.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #3 ·
hi - thanks for the reply - yes i tried the test :

turbo seems ok - no visible smoke in the exhaust - phew..

still concerned though - i've been driving very stately since this problem arose, trying not to smell oil!


must be a leak onto the cat or somewhere hot:

is it the oil pressure sensor at the bottom, front right of the block? this looks like a possible culprit.. the oil feed pipes for the turbo could also have a slight leak one was replaced a while ago for corrosion the other is original.. i don't want to go replacing things unnecessarily...

under boost, what part of the oil system that could be leaking is under most pressure?

thanks
 

·
Registered
Joined
·
1,025 Posts
Hard to say really, there are numerous points of oil escape. When the engine is cold, wipe off any wet/damp looking oily areas like around pipe ends especially around the turbo. Also, check around the sump, wipe off any fresh/damp oily patches, and take the car out till it's warm. Then open the bonnet and look around for any fresh oily patches and under the engine around the sump really. If they are all ok, then I'd take a guess at possibly the valve stem oil seals possibly.
 

·
Registered
Joined
·
1,036 Posts
non return valve coming off the cam cover, is it now leaking ? means the engine is getting presurised & you blow out oil via the breather system, especially under boost,
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #6 ·
thanks for the advice -

so far i've replaced that cam cover grommet - the old one fell out - and a little bit of vacuum hose - i have the rest to do though..

so far no change and i didn't previously mention that the in dash boost gauge is showing less boost now too - i'm pretty sure this coincided with the oil smell on boost and the loss of oil..

gauge moves but i only get boost into the lower yellow and the car definately feels slower -
 

·
Registered
Joined
·
3,938 Posts
Your non return valve in the PCV line running from the intake to the cam cover has failed. This is the grey and white thingummy. You can test it for integrity but why bother. These are so cheap just fit a new one.


You may realize that this turbo engine needs a sealed crankcase ventilation system to comply with California emissions rules instituted in 1968! You may also realize that a turbo engine might be tricky to set up with a sealed crankcase that draws blow by combustion gas into the intake.

There is frequently no vacuum in the intake in a turbo engine so crankcase gasses would have nowhere to go. SAAB cleverly devised an open system with no PCV valve in the boosted side of the ventilation system. There is however a tiny non return valve in the vacuum side which opens when the turbo is not boosting and allows crankcase gasses to be drawn into the intake as for normally aspirated engines. When the intake is pressurized under boost this valve closes and instead the gasses are drawn down the larger diameter PCV hose into the compressor intake. Inside that larger hose is a coolant hose to prevent icing blocking this hose.

Older versions of this engine would blow their seals when the PCV system iced up. Your engine is showing signs of failure of the PCV valve allowing turbo boost to pressurize the crankcase.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #8 ·
SOLVED - aero - oil loss / oil smell on boost

thanks for all the ideas and help..

back to normal now! I replaced all the small bore vacuum hose. The only one that was really bad though was between the bulkhead and the cabin..

I also replaced the PCV valve (although it seemed ok) and I put a split pin in the wastegate actuator rod as the clip had fallen out, although the rod was still attached ok.

with this done boost was back and no oil smell! I presume the leak was causing the pressure to rise in the crankcase forcing oil from an old seal or somewhere..


adrian
 
1 - 8 of 8 Posts
Top