Thermostat woes

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#1
I had a terrible time doing the water pump and the thermostat:

1. I went to tap the water pump out; both places where the M6 screws go in to tap, cracked under the pressure but the pump did not budge. I ended up using a 4 ft Crow bar using the valve cover as a fulcrum to pry that damn thing out. Then when I took it out, I inspected it. The impeller was metal, but it had several cracks in it (one very substantial) and a part of it literally crumpled in my hand! (it was rusted out) Is that normal?

2. The thermostat: No problems until I went to reinstall the housing. I noticed that the gasket seemed funky when I removed it; it appeared as if the previous owner or mechanic put the regular gasket and then some of that liquid gasket all around it. It took me a good 3 hours to clean everything perfectly without gashing or goudging either mating surface. I reinstall and start refilling the radiator. The thermostat housing is leaking like crazy; everything was torqued to spec. I took it out, annoyed that I would have to buy a new gasket and inspect the mating surfaces. No gashes, no remains, nothing! So, then I measure whether either the thermostat housing or it's seat was warped. The thermostat housing was warped! Pretty bad; almost 3 mm on one side. How the hell does that happen? So I had to order it from BMW; not bad only $32.86 and $6.86 for the gasket. Online was still cheaper, but I got it within two days.

Then bleeding was a messy pain in the ass. And because of all the horror stories about e36s overheating due to incorrect bleeding, I ended up being extremely anal about it and kept adding and adding until I was absolutely sure no bubble arose. My capacity was 6.5L and I ended up using/wasting 7.0L. That was annoying.

Then when I was replacing the passenger side rack & pinion boot, I noticed the tie rod boot was completely split. I went and did that as well while everything was open. My tie rods were replaced only 35k miles ago, and only the passenge side was split. Driver's side was perfect. Any thoughts as to why? WOuld constantly scraping a curb when curb parking cause that?

Put on new tires, got an alignment, and balanced all four tires; test drove her and she was great! Heat is working again. Nice and toasty! Temp gauge is perfect and all.

The car started handling better than I remember.

I am curious as to how the thermostat housing got warped? Any ideas. My main concern is that it warped due to the car overheating at some point prior to my purchase and whether there is anything I should look out for.
 

Big Daddy

Senior Member
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#2
Wow, sounds like you were very busy and frustrated there for awhile! The metal can corrode when the coolant is not replaced regualrly as it becomes corrosive. Be sure and replace your coolant every two to three years. In some cases adding water wetter, by Redline can help. Also be sure your using distilled water. Pelican Parts article on this subject is invaluable, Pelican Parts

And yes you could break or split a boot by constant curb rubbing.
 
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#3
That's the thing, since I've owned the car, it's been replaced every 2 years and I only used distilled water. And the maintainence book shows that the coolant was replaced every two years. This is why I was perplexed. And in truth, the coolant in the radiator was extremely clean. It wasn't discolored at all. The radiator had no sings of rust anywhere; just the water pump. Oh well, glad I replaced it.
 
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#6
Kirby said:
The thermostat housings are known to fail. Heat cycling warps it. Just one of those things.....
THat's good to know. I still think it's ridiculous that it should warp so drastically, even with heat cycling.

Thanks.
 
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#7
Big Daddy said:
Double check your engine and body grounds, if they become disconnected or dirty they can allow the coolant to conduct electricity to a negative effect.

I'm sure that there are many body grounds; any problem spots that would be a good idea to check first; I really would not like to look for each one and then inspect them.
 
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#8
check the fat lead that goes directly from the battery to ground, check for any shit around there, then check the main strap that goes to the engine.
 


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