oil in the coolant reservoir ....crap!

[Hu Flung Dung]

Hello all!

1991 900 5-speed 16V NA.......saturday went to check coolant level, found it low and a nice thick froth of oil on top of the coolant. No coolant in the oil, no loss of power, no smoke, etc. and no overheating yet....doesn't have an oil cooler either.

Anything else to check or is it as I fear, head gasket time?
Also how come it's not the other way around, coolant in the oil? Is the head more likely to be cracked?

Thanks and cheers to all -

[Steve Corgan]

I'm really sorry to hear that Hu. It sounds like a HG to me.

Both oil pressure and coolant pressure are relatively low compared to the compression in the cylinders. I've only done two head gasket jobs on 900s and on disassembly it was obvious that the failures occurred next to a cylinder / water jacket in both cases. The high pressure from compression broke through the gasket, forcing oil, fuel, and combustion gases in the water jacket. Give it time and water will find it's way into the oil too.

Another thing to look for is air bubbles in the coolant reservoir tank. The engine should be hot and running when you check. Try varying the rpms. The bubbles of course are caused by the cylinder pressure leak. Also, when you start the car up look for white smoke out the tail pipe. When you shut a hot engine off, of course there's no compression pressure, but the coolant pressure rises and forces coolant back into the cylinder. Hence the white smoke tainted with anti-freeze smell.

It will take a while to deal with it, but don't *** out too much. (I just found out that *** is a bad word. Over here it just means depressed. What does it mean across the pond?) It's not that hard of a job to do and there is plenty of online DIY walk throughs.

My first HG was on the 87 900S. My wife noticed it was running hot and so decided to head straight home. Of course home was 75 miles away. She drove it until it literally wouldn't run any more. At first I thought that the engine was toast and since we didn't have the money to fix it we were looking at junking the car. Up to that time I'd only done things like brakes and general maintainence. So I thought, "What the heck, I've got nothing to lose."

The head was so distorted it couldn't be straightened or machined, so I found one at Pick 'N Pull for $60, had it tested (perfect), and put it on. (Your head is likely in excellent condition and Saab valves last forever.) Throughout the process I kept doubting myself. We've put over 100k miles on the car since I did the HG and it's running great with over 310k miles. That's 500k kilometers!

Take heart. Your car still has lots of life left in it.

[16saabs]

even when you have changed it there always seems to be an oil film in the water top up bottle so don't panic once it's been done, if you still see it there

[Earth Brown]

drain coolant, and refill.

See if it comes back, dont panic yet.


K

[Hu Flung Dung]

I appreciate your help! Cheers-

[jedpa74]

My 93 has this issue as well. Removed and cleaned the coolant tank and the oil returned. I have no doubt the head gasket is bad. Since the coolant isn't showing in the oil and the cash for the gasket kit, head bolts, head bolt socket, and mercedes coolant isn't showing in my wallet, I still drive it on short trips. I am looking forward to changing it when the time comes.

[gorper]

Originally Posted by jedpa74

My 93 has this issue as well. Removed and cleaned the coolant tank and the oil returned. I have no doubt the head gasket is bad. Since the coolant isn't showing in the oil and the cash for the gasket kit, head bolts, head bolt socket, and mercedes coolant isn't showing in my wallet, I still drive it on short trips. I am looking forward to changing it when the time comes.

You don't need to replace the head bolts. It's very rare that they are stretched. If you are nervous, measure them all to confirm their lengths are equal.

With your '93 with a B212 engine, be prepared for pitting at the coolant passages. The longer you go with a blown gasket, the longer you'll be exposing the block to acidic coolant. If you haven't been to Townsend Imports' site already, try here for more information on pitting, head bolts durability, and headgaskets:

http://townsendimports.com/Web/2poin...ock_repair.htm
http://townsendimports.com/Web/engin...sket90016v.htm
http://townsendimports.com/Web/cooli...der/2.1jbw.htm