So im trying not to freak out about this. My first thought was blown head gasket but im not sure if that is the case and thought i would get some opinions. I have a 2007 MCS with just under 53,000 miles. I have a little bit of what looks like oil in the coolant reservoir. there is a tiny bit of brown gunk stuck to the reservoir walls and a kinda of rainbow effect to the cooant. not a lot, just a little bit. the engine oil is not milky, i have no white smoke and the engine is running fine. the only symptoms are the little bit of oily substance in the coolant reservoir. any thougts on what this could be or what i should do?

 

Compression, leakdown and/or uv dye tests. Delay taking that summer vacation, you might need the bucks to do the head gasket. Has the car recently gotten hot?

Quick test: let the car cool, remove reservoir cap, start the engine and look for bubbles.

Every time I've thought, "Head Gasket"... it's been the head gasket.

Good luck!

 

Have you ever changed the coolant?

 

i have had the coolant changed once, im concidering just doing a flush again and then monitering it to see if i see any gunk again. I have gotten my cars oil changed at a local shop and i let them top the coolant off and i was thinking maybe there coolant jug was just oily and got some in the reservoir.(wishful thinking) im going to continue to monitor it to see if the oil substance gets worse in the reservoir and im going to take it in very soon to get a compression test done.

 

I've seen a lot of gunk in reservoirs over the years, don't know what it comes from. My 3-year old Jeep had crud in the reservoir, nasty brown. Same with my wifes Sentra. Don't worry just yet. Might be just crud.

 

Thanks, i was kinda thinking the same thing just because the engine oil is fine and im not noticing any smoke or engine performance loss. i'll keep monitoring it.

 

Would it be possible that mixing coolants could cause this gunk in the reservoir? when i last had my car into get the oil changed at a local shop they topped the coolant off because it was low. they used a long life coolant but it wasnt the bmw coolant. could mixing the coolants cause a gunky/oily deposite in the reservoir?

 

Yup.

Never, ever mix coolants.

I used to say...



Perhaps I should make one up for Mini...

 

so what are the issues that could arise here from me mixing coolants? If i get new coolant put in, do you think all will be well? also what are your thoughts on the flush's the quick lub shops over where they use a machine to force old coolant out and put new coolant in? i wasnt sure if i should do that or still with a drian and fill method.

 

If you mix coolants you basically weaken the coolants as they more or less start to fight against each others additives. * I'm saying this since you don't know they they put in there.. You'll end up with slimy crud in the system.

I don't like the chemical flushes, they are too harsh and not needed. (The can-o-crap that gets dumped in, then drained out...).

We have a coolant exchange machine at work. MY beef with it is, that there is ALWAYS left over coolant in the tank and lines.. no one every bothers to fully drain the machine... they are only really good for sucking old gunk out... That.. and I'm sure whatever coolant they are using is the cheapest crap the quick-lube has in stock.

*I* prefer...

Drain... fill w/ 50/50 of Distilled H20 and your proper G48 (BMW/Mini) spec coolant.

Run car... until hot... let it safely cool down..

Then again..

Drain... fill w/ 50/50 of Distilled H20 and your proper G48 (BMW/Mini) spec coolant. You dont have to get it from the dealer.. ECS and German Auto Parts sell 3rd party spec coolants as well as the OE products. (and lots of other car makers use it as well..)

http://www.ecstuning.com/Mini-2011-C...ant/ES2622910/

I'm sure then you'll be quite all right, and I can pretty much assure your oil slick in the coolant bottle will be long gone.

I've never had that method fail. You'll get a solid clean mix when done.

And, I don't think its a head gasket. You would have major coolant lost... water mixed in the with oil.. overheating.. etc..

 

thank you! this was really helpful.

 

That's not a bad price. I really should swap mine out. How much coolant does the MCS hold? (if you know off hand). Though I probably wouldn't put brand new coolant in just to rinse the system. Straight distilled water should work, should it not?

 

Cooper 5.6 qts
Cooper S 6.3 qts

Keep in mind thats 50/50 mixed with distilled water.

About half of that volume stays in the block when you drain it.

https://wiki.bentleypublishers.com/d...C4A79A922EEA13

Shows the refill process for the N12 engine.

To drain, I just prefer to pull a lower hose.

http://www.realoem.com/bmw/showparts...31&hg=11&fg=35

Shows the much needed bleed screw access to get the air out. Its part #8 in that diagram.

 

HMM, so I wonder how many times I would have to drain, fill, run, drain, fill, run, repeat, to get all the prestone out. It was in the car when purchased. Or if I should just leave it be since the car is not overheating and there is no obvious crud in the tank.

 

If its clean... Chances are its ok..,


I dunno, I just don't know why people settle for the wrong stuff being put into the cars... It's not helpful... And cost about $10/service to do it right.

 

the joys of buying used. Checked coolant on inspection. Didn't think anything of it being green since the newest prestone is supposed to be pretty universal. Might just leave it alone for now. Bigger fish to fry (carbon cleaning, heat shield, spark plugs).

 

Way bigger things to worry about- read this thread.


https://www.northamericanmotoring.co...ant-flush.html

 

Yeah, seems no real consensus other than mixing different coolants is bad

 

Well if you took it that way, you should read again.

 

Why don't you just state your opinion instead of beating around the bush? Some think you have to use OEM, others use prestone and their cooling system is fine.
Got any pictures of sludge formation in aini from wrong antifreeze use?

 

Calm down. My opinion is in the thread. I'm done arguing my point.