[n811]

Hello Everyone:
I have a 2008 B207 wagon (180k miles) with a few umm... issues . It's losing coolant at a regular rate. It's got a pretty good oil drip from the bottom of the oil cooler. It's got oil in the expansion tank. Ugh.

I replaced the thermostat housing at the start of COVID lockdown, as it had an obvious leak at the housing/block seal. (not an easy job without removing the catalytic converter, but I was able to do it!) At the same time, I replaced the seals on the power steering pump to try and eliminate that as a source for the continuous oil drip at the bottom of the oil cooler (hey, start easy, right?). For anyone looking, here is the kit with viton seals/o-rings:

93201201 by Aftermarket | Power Steering Pump Seal O-Ring Kit

93201201 by SAAB | Power Steering Pump Seal O-Ring Kit | Fits Saab 9-3 | eSaabParts: Saab Parts, Done Right.

www.esaabparts.com

The oil cooler still has oil dripping from the bottom of it, plus there's still a thin film of oil in the (brand new) expansion tank.

The oil cooler has obviously failed in some way, but I was shocked at the cost of OEM replacements. My question is does the actual cooler fail internally, or is it just usually the seals where it attaches to the block? Do you have any advice regarding diagnosis (oil cooler vs. head gasket introducing oil into coolant)?

 

[steve12955]

Hope that the oil cooler has failed internally (it’s easy to change) allowing oil under higher pressure to enter coolant passages. Or, it’s the head gasket.

When the engine is running do you see any bubbles in the reservoir? Suggest that you get a kit to test for exhaust in the coolant.

 

[n811]

I just tested this and found no bubbles in the reservoir with the engine running. The combustion gas leak test showed negative:

Which is great news, for sure. Could oil be getting into the coolant due to a leak internal to the turbocharger?

 

[steve12955]

That is good news. I suppose if the turbo housing is cracked then oil under higher pressure could be infiltrating the coolant jacket, but it's more likely the oil cooler. That would be the easier and cheaper fix: $30 used, $60 new on EBay.

 

[n811]

I'm researching the oil cooler replacement and I'm confused on exactly what I need. Most coolers for sale online appear to just be the "heat exchanger" part, if that makes sense.

The OEM part has a heat exchanger attached to a housing - which looks just house the oil pressure sensor according to this picture from WIS online. Most of the aftermarket parts I've found online are missing this entire housing, like this one from eEuroparts.

My goal is to replace both the cooler but all o-rings since it's leaking oil externally. The diagram of the part shows a couple of tubes running into the oil cooler (part #23) with two o-rings. However, there's an oil cooler o-ring kit that has four o-rings. I'm confused on why there are four rings in this kit, where only two are shown. What do the tubes go to?

If I go the aftermarket cooler route (vs. OEM), am I missing out on replacing potentially leaking o-rings where the housing attaches to the block?

 

[pointemstraight]

Did you ever get your oil cooler replaced? Mine is having the same issue (minus the oil in the coolant) - it's a constant post-nasal drip of oil under the power steering pump connection. I'm starting with that seal kit first but may very well end up down the oil cooler path you're on.