I put this in a different thread but perhaps this might be a better place for it since it came up during the thermostat housing replacement. I learned my lesson, keep the number of new threads to a minimum - I have this spread all over the forum. Sorry


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Hi everyone!

Finally finished up the job. it was the water tube leaking. Supposedly it was replaced when the water pump was done in April, but I seriously doubt that.

I've attached a couple of pictures. The o-ring and plastic remains are what I fished out of the water pump housing and you can see the end of the tube is destroyed. No wonder it was leaking.

A couple of thoughts:

I would never do the thermostat housing again without unbolting the intake manifold. It is six bolts and it is no problem removing the passenger wheel to get at the lower bolt. It took me a ratchet and a pipe for leverage to remove it, but I suspect it was gorilla'd on the last time it was off. I know most how-to's don't mention this so user's choice I guess.

Removing the manifold gives unrestricted access to the water tube and if nothing else, it was easier for me to unbolt the manifold than to try and put that stupid clip on blind (I missed it last time BYW - it felt seated but when I had the manifold unbolted it was nowhere near the grooves.)

When replacing the water tube I put lube on the entire space of the water pump housing and a little bit on the o-ring. I recommend silicone grease - I know I use it for SCUBA diving because vaseline etc. can break down the o-rings, but there are mixed notions out there.

A racquetball ball is the perfect size for the thermostat side of the water tube. It fits in the opening and gives a large area to push on with the right hand while I used my left hand to guide and twist the water pump side of the tube.

I used Pentosin Pentofrost NF coolant. I used BMW the first time through, but after it leaked out I removed the rest and was unwilling to drive the hour and a half to get more. The Pentosin lists Mini compatibility and it's blue. It is also available in store at O'Reilly 90 second from my house. Works for me.

To drain the system I removed the radiator hose on the coolant tank side and use a shop vac to drain the system. Unscrewing the bleeder screw made it drain more quickly, even with the cap off the coolant tank.

I ended up draining my system 5 times. Originally I drained it and filled it with water and Prestone flush - someone had used Dex-Cool in it. I then flushed it with water twice. I finally filled it with 50/50 BMW - which promptly leaked right out. After replacing the water tube I flushed it with water again finally filled it with 50/50 Pentosin.

Careful of brittle stuff - when removing the manifold the PVC hose snapped - totally brittle. I simply snaked a hose inside the old one and used shrink wrap to seal it. It is not perfect but I don't really have $80 for the hose and I am not in the mood to remove the manifold to replace it when it gets here. So far no CEL and it is basically a breather so it should be fine.

The hose clamps are a major PITA but if you are using regular pliers the easiest way to get a grip is to use the serrated "bottle cap opener" part of the blades keeps the clamps from slipping. Still one of the most annoying parts of the job for me - YMMV.

When replacing the manifold screw all the nuts on finger tight then torque to 11 ft/lbs. I don't have a torque wrench so I went with snug. Same thing for the thermostat housing bolts.

Finally, I can't remember what the actual procedure is, but I forgot to unscrew the bleeder screw the first time I filled the system and it won't fill properly, at least it won't for me. Unscrewing that bleeder screw while turning on the heat etc. allowed it to fill quickly and fully without major air in the system.

Thanks everyone for the help - the hardest thing is doing it the first time when you are unsure exactly what to unclip and unbolt. The thermostat housing itself is easy peasy lemon squeezy and the manifold is even easier IMHO.

BTW, the Bremman housing is EXACTLY like the stock unit that came off the car, so my advice is save your money and buy after market rather than OEM.

 

Yes, I Agree there! I neglected to replace my water pipe when I did the tstat and really regret it even though I have no leaks. Still on my original water pump but know it will have to be replaced and then I'll have to do both, and unbolt the tstat to do it, which means I should unbolt the intake manifold, and check the valve build up yada yada yada.

Also, I can't recommend highly enough the use of an Airlift system to draw a vacuum to check for leaks and perform a bleed free fill. I've used mine a dozen times on mine and orhers cars and it is a truly must have tool when working on cooling systems.