First off I'll introduce myself, my name is Marc and I come from the VW world.

My girlfriend has a mini and it has had some over heating problems. I went through a bunch of trouble shooting, and read through some of the common problems and everything seems to point to the water pump.

I have found a few of the well written DIY's and plan on doing the pump myself, just have a few questions.

1) How important is is to use an OEM water pump?
2) In addition to the water pump, some anti freeze and the o-ring from the pump to the block, what other parts will I need for the swap?
3) Any tips or advice?

Thanks for any help

 

Hmmm, a few suspects here:
1. Bad waterpump.
2. Worn supercharger-waterpump drive gears due to oil starvation from seal leak. Makes the charger rattle. Swap a new or rebuilt charger & pump or just mod an electric waterpump in. Search what Raven Mocker did in this forum.
3. Bad thermostat
4. Dead Rad fan or dead low speed resistor. Check all fuses. Do the resistor mod or bypass if only the low is gone.
5. A dead power steering fan can blow the common fuse that drives the rad fan
6. Air in system. Bleed properly from 2 bleed screws.
7. Leaky coolant tank & cap
8. Radiator issues.
9. Dead alternator, but you'll know if it is.

 

Guess I should have clarified, it's a base 2003 Mini Cooper. Non S.

 

Oh, so the supercharger drive & coolant tank issues won't concern you. All the rest could possibly cause the problem.

 

Brand of the pump is not a big deal....the cheapest ones have plastic impellers...so can fail fairly fast...same for lower quality seals on the cheapest.... So OEM is the safe bet...but to save $20-30 on a 3-4 hr job...go for it....
Be 100% the system is full....several leaks happen...and the cooling system is a pain to bleed...an airbubble will result in overheating....good luck!

 

2 things are what pointed me towards the water pump, first tip off was the wet spot of coolant under the passenger side, looked and saw a good bit of coolant had dripped onto the AC condenser.

I also tried just bleeding the system and found at the bleed screw on the upper radiator hose the hose was dry, started the car, ran it to temp and just a little bit came into the hose, and was unable to bleed the system. Which tells me the thermostat opened but the water pump isnt doing anything.

 

Sounds low on coolant....
If the condesor (by the rad) has coolant dripping...might even be a radiator leak...
Fill and bleed....you FOUND AN AIRBUBBLE.
I always found idling does not open the thermostat enough...some extra rpms are needed.

 

I had her rev the car a bit while I continued watching where I removed the bleed screw on the upper radiator hose. Also the expansion tank was on the max line and the system didn't pull any from there.

Should I have opened one of the other bleed screws as well?

 

Yup...all the bleeds...not sure on the non s...
But s has 2...one is above the rad, the other on the tthermostat housing.coolant should GUSH out with thermostat open....
If water pump is failed....or very worn...guess you could see much less...but rule out the basic stuff first...
Many minis have NEVER had the cooling system serviced....a 3 year item......

 

Thanks for the info

From what you're saying and what I understand it really is the water pump.

Other than the pump, and some coolant is there any other parts I should get?

 

I had a similar issue with my '02 R50. There are 3 bleed screws....1. on the upper hose, 2. near the battery box and 3. near the right front of the engine head to the right of the oil dip stick. Add coolant at the filler cap near the battery not the overflow tank as you bleed (recap between top offs as you bleed and take your time letting it cool before opening cap).

Mine ended up being a radiator leak on the top left of the radiator about the same place you describe seeing fluid drips. The radiator replacement is alot easier than I thought. Good luck.

 

I will check and see if it is a leak from the radiator this afternoon. Would be nice if that's all it was. If i can't find anything there I will attempt to bleed the system again.

I had trouble getting the pressure cap off? Twisted it counterclockwise but it wouldn't come off. Didn't want to break it. Am I doing something wrong or should I just use some more force?

 

After turning counterclockwise to the stop try pushing down and twisting another quarter turn. It keeps the cap from blowing off as you release pressure.

 

Awesome. Thank you.

 

Replaced the pump yesterday, I was able to finish in about 4 hours. It wasn't bad at all. Here's a few shots of the process.

 

duplicate

 

duplicate

 

Nice work....glad it wasn't too bad for ya.

 

bringing this back, no more leaky water pump but we are still loosing coolant. No white smoke, and can't seem to find any other leaks. I fill the coolant tank then after a few days of diving it goes down under the minimum line. but we don't lose any more coolant. There is a bad smell from the AC when running, is it possible that there is a crack in the coolant reservoir and is leaking onto the exhaust?

 

More likely the radiator side tanks are cracked....they are plastic....and they get brittle after 10 years ...about $100 on rockauto for an exact fit copy...
Guess the tank could be leaking...but it is not under pressure like an s....
Hoses looked good? Thermostat housing and thermost gasket issues are VERY common...I would look there first...

 

P.S.
Bad smell from ac is most likely mold...various products are sold to kill it...if this happens, the drain line is usually plugged....
Coolant has a distinctive smell....if you do smell coolant in the car...then the heater core is a possible issue.

 

i will check the side tanks. All the hoses looked good, i looked closely at the thermostat while i had the front of the car off and there was no coolant over there at all. Will double check again though.

Thanks for the input