Oil in the coolant

[nick.cbr]

Hi all,

First post. I tried searching for head gasket, head+gasket, headgasket, coolant oil, etc. and didn't really find what I'm looking for.

I just bought an '89 325iX as a project car. It's pretty clean with minimal rust and the interior is mint. The car runs great, starts great, has a bunch of new parts, etc. It has it's suspension issues and the dumb stuff like the brake lining lamp is on but it has been a great car the last 600 miles.

Anyway, I took it in for a checkup and an alignment and the shop calls later and says I have oil in the coolant - like a lot. Ok fine, maybe I got more of a project with the engine than I thought. They say the motor is probably junk and I'm almost in shock. I drove it there, I've driven it all weekend and week to work and back. A ton of miles and the temp gauge has never gone up and there are no signs of the engine overheating. In fact, it doesn't even get to half way - it runs at like 1/4 of the way up.

So I went to google and found that people have had issues with head gaskets going and leaking oil and a local guy I get my parts from says not to worry - yet as the M20 can put oil in the coolant and it's probably a head gasket.

The shop ended up putting a pressure tester on the thing and promptly blew up one of the radiator hoses (which is looks pretty darn new I might add).

Anyway, has anyone heard of oil in the coolant on the M20? We dropped the engine oil and there was no coolant in the oil. The engine does have an oil leak and the most of the right side of the block is damp and oily. I have also seen that there is a gasket that can leak by the oil filter housing and possibly some sensor that goes in the block.

Thoughts on any of this guys? I'm going to take the car to a different shop after they fix the hose tomorrow.

I still love the car and know they have headgasket issues so none of this is all that surprising; just annoyed they broke my car even more than it was and are charging me for it.

Thanks!

Nick

[paperplane94]

A little Oil in the coolant is not something to freak out about, they are old engines.

Coolant in the oil, however, is a little more concerning. Milkshake = bad.

As long as the compression in the cylinders is within normal range you shouldn't be seeing much more than oil in the coolant. You can also have the exhaust gasses checked for any traces of coolant for further testing.


Another thing is that the oil you see might be from the Auto Trans cooler lines that run through the radiator, is it an Auto?

[Exodus_2pt0]

There is no reason why they should have blown a radiator hose during a pressure test.

They should not have gone over 1 bar (15psi) Which is normal operating pressure for most engines.

Oil in the coolant is OK, replace the radiator and head gasket with a good flush and you are ok.

Coolant in oil is harder to clean, the block will need to be dipped.

[nick.cbr]

Hey guys,

The blown hose was a total surprise for sure, the first thing I thought was "jeez, did ya hook it up to your shop compressor and walk away for lunch?" I contacted the original owner who said he had a hunch the head gasket was on it's way out (I'm fully convinced he wasn't he wasn't trying to hide anything, this guy is a long time BMW guy, 250K on a mint E39 530, 2002 owner, totally legit) but surprised they called the motor junk as he had a pile of (recent) paperwork with the car from a very reputable BMW shop showing no indications anything was about to blow up - could be bad luck too - not sure. I wish I had done the smart thing and brought the car to this shop in the first place though (where this car and the M3 are going from now on).

Anyway, he said the he did check the compression on the engine and cyls 1 and 6 were "lower" but not any cause for concern in his mind.

I would have been a lot more concerned if the oil was full of coolant but that wasn't the case, it was just oil.

The car is indeed an auto. I will say, the tech got about 1.5 cups (1 cup=the thing you use to measure stuff for baking) of oil out of the system but I have no idea how it was seperated. Regardless, it seemed like a lot to me but I have almost zero knowledge of this engine so that must be considered as well (the tech was a younger guy who admitted he had little experience with older BMWs too which had I known this....). The radiator was replaced with an aftermarket radiator about a year ago so who knows on that.

Can someone explain the automatic transmission correlation with oil in the coolant a little more in depth - is it different than any other setup where the trans fluid runs through the side of a radiator or same basic setup?

Also, are the heads on these engines prone to cracking or do most people throw a head gasket in it and put the head back on with new bolts? I have ordered a new OE BMW head gasket kit and new head bolts. Anything else I should do as long as I'm in there? I refuse to give up on this thing as I love the car!

Thanks guys,

Nick

[FLG]

All cars with an auto tranny will have a cooler of some sort, most have it built into the radiator some have an external cooler. If you look at the bottom of the rad you will see 2 cooler lines going from the tranny to the radiator, if there is an internal leak coolant or oil can leak from the tranny to the coolant or vice versa.

BTW where are you located? Maybe someone can help you out.

[nick.cbr]

Ok that's what I thought... It's hard to say if it's engine oil or really dirty trans fluid but if I had to guess, it was probably from the engine.

I engaged my local parts guy (Minneapolis) who has been around E30s forever and has a few of them himself - he said that the M20 does this type of thing and it's not totally out of the ordinary. He has contacted one of his mechanic buddies as well to get his thoughts and to hopefully do my head gasket.

Thanks!

Nick

[jlevie]

Since this is an auto, the first thing to do would be to replace the radiator and flush the cooling system to get the oil out. The transmission cooler in the radiator may be leaking and the radiator is probably way over due for replacement. You should also replace all of the cooling system hoses, expansion tank, and cap, as all are probably overdue also.

If oil starts to show up in the coolant after that, the head gasket is leaking.

[Exodus_2pt0]

Inspect your trans fluid, if it is a radiator concern, I can guarantee that it has gone both ways.

[nick.cbr]

I don't mind doing all the cooling system parts as it needs it anyway I'm sure; however, there's still the issue that started this whole mess and that's the fact it loves to leak oil.

But if there's trans fluid in the coolant, doesn't that mean there's coolant in the trans as well? That can't be good lol. In sticking with the blown head gasket, where would the oil get into the cooling system? Are their oil passageways between the block and head or something that are only separated by the head gasket? I'm trying to figure how this guy went from oil in the coolant to blown head gasket or junk motor.

Secondly, if in fact the rad. is the bad part (it is 1-2 years old I'm now told), I still have this crazy oil leak. From what I've read, there is some gasket on or near the oil filter "head" as it's called on realoem that can leak as well as a sensor (oil pressure switch) in the area that goes into the block - I believe it's called the control valve gasket:

http://realoem.com/bmw/showparts.do?model=1503&mospid=47324&btnr=11_4329&hg=11&fg=30

Oil pressure switch:

http://realoem.com/bmw/showparts.do?model=1503&mospid=47324&btnr=11_4300&hg=11&fg=10

Nick

[Exodus_2pt0]

The motor is not blown.

These engines use junk paper head gaskets. The oil and coolant pass through the head gasket to get to and from the cylinder head-block. Eventually the paper gasket will wear down and allow a cross flow between the oil/coolant passages. Sometimes it only goes one way.

If their isn't any coolant in you engine, put a head gasket on it and be on your merry way.

Sounds to me like that mechanic just didn't feel like doing a head gasket. Hell, he blew up a radiator hose during a pressure test. Do not go back to him.

[nick.cbr]

Yeah I think the motor is fine and the guy I trust with these cars said the same thing right off the bat too. I found out the tech has hardly ever touched more than a small handful of M20s so I won't be going back. Live and learn on that one.

Do I have to worry about resurfacing the head or anything like that or can I just swap the gasket and related stuff (whatever is in the kit) and put it all back together? I hope the OE kit I got is improved over the origional stuff. I also got new head bolts as well. I understand that it's hugely important to 1. get the timing right ;) and 2. make sure the head is properly torqued.

Anything else? I've read a couple of DIYs and it doesn't look too bad although I'd rather pay someone to do it.

I'll update the thread as I know more to hopefully help others.

Nick

[jlevie]

In my experience, a used head always has enough warp to justify at least a minimal (0.005") surface cut. If the engine has 100k on it, the head could use (at the least) the valve ground and new seals. If the milage is significantly more than that it may need new guides, rockers, cam, etc.

There are a few common places to have oil leaks on an M20 engine:

Cam seal
Intermediate shaft seal
Main seals (front and rear)
Oil pressure switch
Oil filter adapter (on cars with an oil cooler)
Oil Cooler hoses
Valve cover gasket
Pan gasket
PS hoses
Transmission hoses (on an auto)

The first step in solving an oil leak is to throughly clean the engine (from top and bottom). Then watch for the first signs of oil. When faced with a dirty engine and/or engine bay the process I use is:

1) Start with a hot engine and get front of the car up on jack stands. Several
large pieces of cardboard under the engine area will soak up the grunge and
help prevent stains.

2) Using a putty knife, screw driver, etc., scrape off any heavy
deposits. Most of that will be on the lower part of the engine and you'll have
to get to it from underneath.

3) Spray a mixture of Gunk and diesel or kerosense on using a garden sprayer.

4) Scrub every thing you can reach using plastic bristle brushes on painted
surfaces and wire brushes on bare metal. Work heavily caked areas again with
the scrapers. Spray on more solvent mixture as needed.

5) Re-fill the sprayer with any concentrated detergent (Simple Green, pressure
washer detergent, etc) and spray everything down.

6) Using a garden hose set for a gentle spray, or better yet a plant watering
wand, wash down the engine and engine bay. You want to avoid any high pressure
spray as that may force water into places that you don't want it.

7) Spray on more detergent and go over everything with the brushes, then
repeat (6).

8) Leave the hood open and allow the engine bay to dry for at least 8 hours
before starting the engine.

Notes: Having the engine hot will make oil and grease easier to wash off and
the residual heat will help dry out any water that reaches electrical
parts. You won't get the cosmoline/oil stains off the valve cover on an m20/30
engine as they are baked on. The best way to clean up the valve cover is to
have it bead blasted or hot tanked, but you can get most of it off with paint
remover (with the cover off the engine).

[nick.cbr]

Thanks guys. If I can't find someone that wants to do this (who would? lol) looks like I'll just do it myself.

Part of me wants to put a new gasket in there and put the head backon but I'm wondering how long that will last. The motor has 148K on it so who knows how warped the head is!

Even if this just gets me by until I have time to put an engine in it that would be fine with me.

Nick

[Exodus_2pt0]

Where are you located?

I have a shop in MD, i'll do it cheaper than anyone else would.

[nick.cbr]

I'm in Minneapolis. I have a guy lined up for Monday so hopefully the old beast will make it till then.

Thanks though. I'll update with happy news next week sometime.

Nick