Good Morning Guys,


Long time lurker, figures my first post would be when I need help. Also, apologies for the wall of text and if this violates any rules.


I have a 2003 Mini Cooper S with 72,000 mi. Now recently I was experience the high fan at idle. Okay, do some research and take a look. No coolant. So I refill, I was also about a quart low on the oil (that burn doe) so I filled that up too. Run a quick errand and it seems all is well. low fan and high fan working as they should. BUT I notice the overflow tank has a pinhole in the seam. I've never paid this any mind because as long as I've owned the car (since 53,000) it's had the residue on the side of the tank and never any problems. So I let it cool down overnight and check in the morning. There's no puddles other than what I assume is excess coolant leaving the pinhole in the seam, only about a mcdonalds hamburger bun size puddle (radius, not depth). I check the oil, looks normal although with the new oil it's hard to tell if its low or my eyes in the morning light. But here's the kicker, there's absolutely no coolant in the tank. Definitely not consistent with the small puddle if it was leaking under the car. Also check the oil cap and there's slight discolor to it but not consistent with the "milky, mayo type substance" I've been reading about.
Extra info: Recently replaced the oil pan gasket, oil pan, and oil filter housing (figured I'd get the new one before being forced to).
With all of that being said, I have an idea of what it might be but fingers crossed I'm wrong and you guys can offer some insight on a possible diagnosis before I head to the shop. My wallet and I would rather it's something I can fix this weekend as opposed to letting my baby sit in the shop.



Thanks guys.



TL;DR: disappearing coolant, minor puddle inconsistent with a as much as lost.

 

I'm hearing thermostat housing. Mine seems to have a problem there. No hole in the coolant tank that I can see and no puddling either. I'm going to have to do the shop thing though...

 

First off, I love the name.

Secondly, I've got my fingers crossed that's what it is but with my luck it'll be a slew of things. I have a good shop guy, but damn it at this point I want to get my hands dirty and show this beast who the boss is.

Also, thanks for the insight!

 

Even if it is the thermo gasket which is a known problem on the 1st Gen cars it doesn't answer as to where all his coolant is going.. Granted some of it will puddle on the engine as it leaks from there which gives it more time to evaporate some.. Is the pin hole at the bottom of the tank? if not if the coolant is below that pin hole there is another problem.. which could be the thermo gasket still, and not a more serious problem..

 

the pin hole is on the seam in the middle of the tank. I assumed it was just blowing excess coolant out through there but couldn't tell the level by eye balling it. I assume it was slightly under but just enough to shoot some out with the pressure.

 

Might be able to stroll around our tech articles and see if you can find something that might help you out. Good luck!

-Luccia

 

I think it's the expansion tank. I think when your motor is running, it pressurizes the cooling system and blows coolant out the hole(s) in your tank. The expansion tank is a common problem. The thermostat is a common problem too, but if you know you have a leak in your tank, I'd start with that and if you're still leaking fluid try the thermostat housing.

Both of those things are really easy to do in the garage. Pelican has a great article for changing the tank, and I found a DIY when I had to do mine that made the thermostat a 45 minute job. If I remember right, you just pull out the air filter box, and ecu and then you can get to the thermostat housing.

 

+1

My car had the same problem with the OEM tank a couple of years ago before I bought it from the previous owner last year. The leaking coolant would dry so fast it was hard to tell it was leaking. I suggested then that he replace it with aluminum but he went with OEM anyway. Even though it is fine now, I plan to replace my expansion tank with an aluminum one (from WMW) and forget the inevitable OEM tank split problem.

 

This morning, I looked under the lid after driving to work (I always check in the pm when the engine is cool to check the level (silly me). Low and behold I found it! It is the tank! The seam of the two halves is where the stuff is coming out from the pressure. Kind of a quiet hissy dribble. That explains the whitish crusty stuff on the lower half of the tank. New tank will be purchased soon. It doesn't look hard to do.