Hi folks,

Driving to a gig last night and my temperature gauge pegs. My exit was coming up so I continued on, got off and pulled over. Opened the hood to find brown goop apparently exploded out of my coolant overflow tank (pictured below).

I only had a few miles to go and continued my drive (10 minutes).

While the temp gauge was still pegged - the car never lost power at all.

Made it to my destination and had the car towed home.

I posted to a few groups on Facebook and the immediate reaction was Head Gasket. Came in here and started doing research, and also found that the Oil Cooler causes the same issue.

Am I correct in thinking that oil in Coolant, coming from the coolant overflow container (with no loss of power to car) points to Oil Cooler rather than Head Gasket?

I checked the dip stick today to see if there was any of this sludge in the oil and I saw none, saw no oil either which I assume is now in the radiator and all over my engine. Pulled oil fill cap and saw no signs of peanut butter in there either. Recently changed my oil and have had no leaks.

If it were in fact the a blown head gasket, wouldn't the oil be coming from around the head itself, rather than shooting ip through the coolant overflow tank?

Just trying to educate myself before I get the car to the shop Monday morning.

Thanks!
T



2004 Cooper S

 

Holy moly!
First of all, clean all of the gunk off.

Then flush your coolant and do an oil change.
If you suspect you have an issue with your head gasket, do a compression check.
Check your hoses to see if there's a oil leak.

Btw, if you blew a head gasket, you'd see a lot of steam/coolant coming out of your engine.

I have no idea what this brown goo is...Good luck.

 

The brown mess is oil mixed with coolant.

No steam coming from the engine other than what you see in the photo cooking.

Also, no smoke in the exhaust.

Grrrrrr

 

Check out this recent thread, where I dealt with the very same issue. Also, after I fixed it, had an overheating issue where the cap on my coolant expansion tank failed, as it no longer held the appropriate amount of pressure.

 

Yes sir I read that thread earlier before posting here.....
Which actually led to my question here.
I feel like this is the oil cooler (heat exchanger - these are one in the same correct?) rather than head gasket, thanks to your post.

So in this case, a new Oil Cooler, and a super flush of the coolant system.

Did you replace the coolant tank with plastic or one of those expensive metal ones?

 

Yes, they're one in the same.

Correct. Once my simple pressure test determined the oil cooler/exchanger was faulty, I replaced it -- along with the 2 rings that go to the housing. While I awaited delivery of the new exchanger, I also removed the entire oil housing to change the gasket that mates it to the block.

Yes... I like the plastic tank, as you can place a flashlight against the top to see where your coolant level is at without opening it up. It's supposed to be right at dead center, where the seam is. They do eventually fail (mine failed at 133,000 miles), but IMO, not nearly enough to warrant paying for an expensive metal one...

 

Wow, looks like someone dumped a McDonald's chocolate shake under the bonnet....For this to be the heat exchanger attached to the oil filter housing, it would have to be a catastrophic failure of the O-ring gaskets...The gasket rings look like thick black rubber bands. Any indications of an issue creeping up to this point ?

Also FYI...and for anyone reading this thread....Never, ever, ever, ever continue driving under these conditions unless you are being chased by a band of Bandito's under a hail of gunfire....ever.

 

The heat exchanger doesn't have to fail at the o-rings to produce the 'milkshake.' It can fail internally, as did mine, where a breach in the passages between the coolant flow side and the oil flow side of the unit allows the oil, which is under higher pressure, to flow into the coolant.

The overheating is a separate issue altogether, which could be caused by a faulty coolant expansion tank, or even just a failed tank cap.

Agreed, that's a sure fire recipe for destroying your head.

 

Trust me, I'm kicking myself for continuing on.... But I'm a sound Engineer and HAD to get to the show to get the band up and running.

Ugghhhh

 

I'd say heat exchanger is most likely. From what I've seen, head gasket is more often coolant in oil rather than oil in coolant. I just replaced my head which was cracked in 4 spots and the gasket was blown. No oil in coolant, but some coolant in oil.

should also probably add that you're going to want to test the head since it was overheating. You may have a head gasket issue now.

 

In all the years I've been with MINI never seen the assembly fail internally....odd. I am curious if this MINI had incorrect coolant type in the system causing the metallurgy of components to corrode....

I dont believe the cap or tank was the issue but the end result of heat exchanger failure. More inclined to think it was the change of viscosity to a "thick milk shake" increasing coolant system pressures and volume above designed specs which resulted in cap breach...basically the cap did what it was designed to do.

 

It's possible -- there were tiny shards of metal that did flush out of the failed heat exchanger when I removed it...
Post #7 of my past thread has a pic showing one of the tiny fragments.

When I first procured my MINI, it did have the 'green stuff' in it... Not correct...
In the early months of ownership, I drained the system, flushed and replaced it with proper MINI-branded coolant.

Appears to be a plausible theory...

 

No smoke in exhaust, mess in coolant overflow? Oil cooler.

Make sure to get two new oil cooler seals with purchase.

Drain oil and coolant>front end service mode>remove radiator and all the hoses you can>remove driverside wheel well>get T30 (I think) Torx bit with 10" of extensions>undo the 4 bolts holding it in.

Take a hose, make some janky fitting with some tape and anything else you can find, and wash that crap out of all the hoses and the radiator as best you can. Connect it to everything you can, try to flush in multiple directions for a minute or two in every which direction you can. Pay extra attention to the radiator, since the fins can catch a lot of gunk.

Putting the cooler back in SUCKS, make sure the o-rings stay in their respective grooves, and take your time putting the Torx bolts back in. Tighten them by hand with the extensions off of the wrench/impact (don't be and idiot like me and strip the bolts), then torque them up properly. Then refill coolant and oil, and burp the coolant.

Not too tricky, if you've got an afternoon, a bit of patience, and your vice of choice to aid with patience, if additional patience is necessary. Here's another fun thread on this topic. Good luck!

 

I found the removal and reinstallation of the oil cooler to be quite easy.

There are two guide pins that help in aligning the cooler when mating it with the oil filter housing. After putting it in place, hold pressure on the cooler with your left hand while threading screws back with the right hand with the aid of an extension. It helps if you can magnetize the torx bit with one of those magnetize/demagnetize do-hickies to ensure the screw stays on the bit.

Also, the two round o-rings, due to their shape and pliability, "spring" into the oval recess - holding themselves in place while the cooler is returned to the housing. Move slow and steady, and it all goes into place rather easily.

 

So, just got my car back from Luis at Preceision Auto Werks in Miami....

OIL COOLER!

Whew!

Thanks to everyone for posting in this thread.

Going for a ride.

 

Good for you!

I know the "whew" feeling, when you escape what at first appears to be a head-gasket job...

 

Yeah, see...that's what smart people do. Idiots like myself try to thread the bolts in with their fingers while holding the cooler in place, and then let the cooler slip 3-4 times as they scream and curse in their incompetence. I even once didn't notice one of the o-rings slipped out of the groove just a little to the point that the cooler cut the o-ring in half, and as soon as I started the car, it started leaking oil...

In any case, glad you got it all figured out! Happy motoring!

 

Yay! Dodged a bullet ! Motor on !

BTW: Green Prestone coolant is AOK, and it can even be mixed with the BMW Blue. Just stay away from any Red and even the Clear universal stuff, even the Prestone clear Universal...

Green = Go

 

Just to muddy the water, Zerex G-05 is clear and is universally accepted as a suitable replacement.

 

Thought Zerex G-05 was yellow not clear ?
Is it phosphate free like OEM ?

I just looked it up, the Zerex G-05 is yellow dude.

 

OEM and Prestone green is definitely phosphate free, while some types/brands ONLY stipulate low phosphate...phosphates are said to be not good for aluminum so not good for MINI. And G-05 was really intended for Diesels (it has some nitrites), which is why it's the brand of choice for Mercedes or VW. That also means it contains silicates which may not be suitable for gasoline engines..they are considered abrasive and over time can contribute to wear of water pump seals, as well as other components. Keep is simple...use the KISS method....Stick with OEM Blue or Green Prestone....Flush out every 30K miles...I didn't get to 231K miles on a 2003 MINI being a test pilot...but do what you want, it's your money.

 

That was a close one, most of the time the oil cooler exchange is the issue. Those pictures look scary and you thin of the worst. Glad its ok. Now clean and flush the coolant.