Oil in the Coolant

The morning my heater blew cold air. A couple weeks ago I replaced several coolant gaskets and hoses while flushing the coolant, so my first thought was that my heater core has perhaps kicked the bucket. Just to be safe I checked the coolant level. And though not low, the coolant is a milky brown. Oil in the coolant. Nuts. So what are common causes of this and where do I look first? PCV valve? Head Gaskets? Is it safe and not harmful to the car to continue driving with this bad antifreeze?

It sound like a blown HG. Compression / leak down tests will confirm. Drive it if you must - very limited distance. The damage is done. You will need to get the oil residue out of the cooling system too. That will take a GOOD radiator shop. On the bright side you may have just moved a lot of sludge out of the heater core. Do the compression tests first - you might be lucky (don't hold your breath).

Head gaskets are no problem though right? A good kit is around a $100 and its not too bad to replace. Or will there be more damage as a result that will cost me big?

Well the head gasket is compromised. Is $1300 a reasonable price to have a shop perform the service? This is beyond my mechanical skill level. The $1300 would get all gaskets needed, and a machine shop would go over the head and make sure it's good to go. Any thoughts on my options here?

I've not replaced a head gasket on my E30 though I did once on a Saab 96 V4 and my Grumman step van with a 6.2 GM diesel. I'm guessing that if you did it yourself and had the heads done while you were at it (only makes sense) your cost would be $600 or $700 at least so the $1300 figure doesn't seem too outlandish. It would be a big job to undertake, and if you're not confident to do it, as you pretty much said, could be dicey. I'd be tempted to do it myself. A savings of $600 would be nice.

I'd suggest u might just have to bring it to a shop if you're not sure enough doing it yourself. It would cause more trouble if you force yourself doing it your own.

you will also need some special tools like torque wrenches and spark plug tools etc, which if you dont already own will eat into that $600 "saving"

the cheapest solution would be to swap in another M20. much quicker and easier than doing a head gasket. surprising isnt it.

Well, true enough, if you don't have the tools, there is that cost. Swapping in a new motor doesn't seem too cheap nor easy however.

IMO go for the head and head gasket. If your engine is M10 it is quite easy with a manual. Hire or borrow tools you don't have. The biggest cost is having the head serviced which is a must. Have you checked pressures and leak-down rates yet?

Originally Posted by BMWFatherFigure

IMO go for the head and head gasket. If your engine is M10 it is quite easy with a manual. Hire or borrow tools you don't have. The biggest cost is having the head serviced which is a must. Have you checked pressures and leak-down rates yet?

It's the M20 engine. No leak-down test, I'm not familiar with that. And the compression test reported close to 10-1 compression. So compression wasn't significantly lost. However a chemical test of the coolant reported significant levels of oil. And being that I don't have the oil cooler that is often responsible for oil in the coolant, head gasket is the probable culprit.

Make sure it IS the head gasket !
They did the chemical test where they checked the coolant whilst running for combustion residue ?
No water in the oil ?

Does the head need to be rebuilt ?
If so, ask the local performance shop what they ask for a rebuild with porting, cam the lot.

Got a buddy who has pulled and replaced cylinder heads (preferably alloy ones) ?

I can't be sure it's the head gasket, but the shop says they're 99% sure. All I could do was the compression test and crude analysis of how the engine was running. The combustion was good and it still ran like a champ. This gave me hope that maybe I caught the broken gasket before it could do any serious damage. I could be wrong, as could the shop.

I thought about asking them to port the head, to my knowledge I won't need a new head. But I figure if they're going to be machining it anyway, might as well ask them to port it right? Why not? These heads are fine to port right?

Originally Posted by cmac2012

Well, true enough, if you don't have the tools, there is that cost. Swapping in a new motor doesn't seem too cheap nor easy however.

the M20s are actually.

the only easier BMW engine is the M40.

unplug the ECU and throttle cable, disconnect fuel lines and driveshaft and undo the mounts and out she comes.

i have done it in an afternoon from functioning car to functioning car. would take a day if its your first time.