Thermostat Housing Problems

I own a 1994 525i. The car recently lost a lot of coolant while my wife was driving it. When I looked at the car to try to figure out what was wrong I noticed a crack right down the middle of the thermostat housing. My first question is "is this common?". The housing appears to be made of plastic so I assume it could be fairly common, but was wondering if there may be an underlying problem. My second question is "should I change the thermostat while changing the housing?" I assume the answer is yes. Is this a project my son and I should attempt to tackle ourselves. The area seems pretty congested. Would I need to remove the belts(s) or anything else for access? It seems pretty straight forward. Would I need any special tools? Is there somewhere I could find a step-by-step with pics? Any help or advice is greatly appreciated.

YES its common with the M50's. You can buy an Aluminum housing so it won't happen.

You can change the thermo, but if you are frugal like me just test to see if it opens at the temp its supposed to in boiling water.

Buy or search google for "e34 bentley manual". That book is the e34 bible and will give you a step-by-step with pics.

I searched for you!:
download the first one OR the searchable one.

http://www.bimmerwerkz.com/forum/5-s...0-a-42558.html

I hate that, a big long Post erased by accidental turning the page.Any ways in short you will need 2 special long wrenches, for Fan removal 32 mm about $40-50 on ebay.make sure not to over tighten the housing bolts on install. Specially the one that goes through the engine hoist hook these bolts can easy strip in the Aluminum head.Its cheaper to uses the composit housing.

You might be able to make do with large channel locks and vise grips, thats what I did to remove the fan clutch nut.

If I decide to go ahead and replace the thermostat, what "opening temp" should I use. I am not familiar with the differences and maybe someone could explain it to me. I have seen everything from sub-100 to 196 degrees. Thanks again for the help.

Its up to you . I have used the 88c and the 92c ... the sooner it opens the better i think. faster heating of occupants. Lower opening temps allows you reach optimal engine temps sooner.

I just replaced the thermostat and housing on my 94 525 m50. I just marked the fan blade & clutch then undid the three small bolts holding the blade onto the clutch. I did remove the radiator so there may not be clearance to do it with the radiator in place. I was able to get the housing in place easily

The only time its necessary to remove the radiator is when removing the engine. It is easy to remove though and will give maximum working space for removing fans,water pumps,thermostats. Plus give you a chance to flush the sediment out that has built up in the Radiator. I understand removing the fan blades would allow you to leave the fan clucth installed but its a PIA to remove just the fan blades.

If you have a local Autozone, you can rent the fan removal tools. They won't be for a BMW but they have the right size and wil work.