So I know there are a lot of threads on overheating (lol? :(), but I figured one more couldn't hurt. And most lead in a different direction.

My 2005 Mini Cooper has been having a battle with overheating since I bought her in February. First time was the serpentine belt breaking and I replaced that and filled her up. Fine for a long while after that. Even drove her 1000 miles to Tennessee and then 1000 miles back. No problems whatsoever. Then the alternator went out a couple of months back. I replaced that.

Shortly after that, it began to overheat. I filled it up. It would be fine for a couple of days, maybe even a week or so and then heat up again. I did an entire coolant flush and refilled it. Worked for about a month I'd say.

Then the two weeks ago, it reared its head again. I replaced the thermostat, thermostat housing and gasket. It worked for a couple of days and then two days ago it started again.

It happens all the time. First time we noticed it after the thermostat change was on the highway around 60 mph. It went up, then came down. Then went back up and stayed up until i pulled into a gas station. Since this ordeal has started, I've learned to carry water. I open the radiator fill cap and steam bursts out. Tons of it. It also blew off the reservoir cap. So it's now a goner (anyone know where I can get one?). So I fill it up and take it home. I get home, I use the bleed valves. Refill it. Works great yesterday morning. Then yesterday afternoon, I'm sitting at the Dairy Queen drive thru and it starts to heat up. I turn it off for maybe 20 seconds. Turn it back on, and it's back at normal temp, runs fine all the way home. Get home, reservoir is between Max and Min. The last few times it overheated, there was water in the reservoir still. I top it up with water, bleed the valves again.

This morning, it overheats while driving, cools at a light. Goes up while moving, cools at a light.

There is also a light scraping/grinding sound for the last few weeks when slowing down and taking off. Maybe the water pump?

God I hope it's the water pump. I can do it myself and it's certainly less expensive than a blown head gasket right?

What do you guys think? Sorry for the extremely long post.

 

Fan works by the way. Turns on and off like regular.

 

Are you just using water or coolant water mix?

 

coolant water mix.

don't think it's related though. i did have just water for a while, and it actually lasted longer in the car than my recent mix.

 

Water boils at 212 degrees and the mini coolant temp runs around 220 so you have to have coolant in the system - probably 50 - 50

 

currently it's half and half. the last time i drained it (sunday night), i did the 50/50 mix and it was overheating Wednesday.

 

head gasket

 

you'll need to check the head for warpage . prolly warped a bit the first time it overheated; then the gasket went . get a pressure test done .

 

well crap. does anyone have a DIY for the head gasket? i'll get the pressure test done.

 

If you do the gasket....get the head sent out to get machined ...changing the gasket with a warped head....even a tiny amount is a waste of time....and money.
Also does you car make a sound kinda like chains dragging/clanking?you might hear it at idle or in 1st gear..if you do it could be the water pump/supercharger gears. I assume it is safe to say your fan is fulley functional....both speeds and it switchs from low to hi before it overheats?

 

yeah, i'll be getting the head milled. anyone know a reasonable price range to get that done?

no sc on here. regular mini. i do hear a slight grinding noise. kinda like the sound you hear when your brakes are going bad. it's one of the things that made me think of the water pump.

And yup, both speeds work on the fan. Heard both speeds turn on Sunday night.

 

Sorry....missed it was a STD Cooper.....good luck.
IMO you might want to spend some money and get it diagnosed before you spend some $$$ on it. But does not appear to be anything extremly simple. Sounds like you did everything right...and the first belt breakage set the chain of events in motion.

 

One more quick check....look at you oil....it should look normal. If it seems creamy, then it is possible antifreeze is mixed with it....very bad for bearings. Not common, but an easy check.

 

dont go off half cocked . it's a strong possible it's a head gasket but not for sure . get pressure test and compression test . check for milk on filler cap bottom. check for same on dipstick . if it is head gasket;simply check it for warpage with straight edge and feeler gauges . if it's not warped no need to spend money machining . and no compression issues or need for thicker gasket .

 

thanks! I'll check that in just a few. i'll be getting a pressure test done and i'm going to go ahead and replace the water pump for shiggles. found one for cheap and it's creeping up on 75k miles now. I'll end up doing it at some point.

 

I was just reading about this on NAM. Few other threads suggest that the coolant tank might have a leak in it. I think that's whats happening with mine.

Is your oil milky? If so you might have a head problem