850 turbo overheating solution

[miklik]

I had an overheating problem with my 1996 850 turbo. It started with my car overheating and it blowing water from the pressure cap/expantion tank. I figured that the thermostat had gone bad. I replaced the thermostat, cap and I still had the same problem of water coming out from under the pressure cap. At this point I should have pressure tested the system. I did find a small leak from one of the radiators plastic end caps. Replaced radiator and still the same problem. After reading all the posts I could find and reviewing everything I was stumped. I finally took a close looked at wear the water was coming from. After about 10mins with the engine running the water would starts to expand, when the water reached the cap it started to slowly bubble out. I ended up finding a crack in the plastic expantion tank at the base of the threads. Replaced the expantion tank and all is well again. I have since talked to another volvo owner who had the same problem and was fixed with a new expantion tank. This must be a common problem after 15 years of driving. I got my new tank at the volvo dealership (which I hate to do but I did get the part quickly) and it was only $5 more than on the internet.

[jblackburn]

Every single plastic part on these cars subjected to heat/pressure is a piece of crap.

I have NEVER had a problem with expansion tanks, radiators, etc. on any other car twice this age.

I recently got an expansion tank to replace one that failed and it was broken again at one of the hose ports just two months later.

[da7]

exactly the same problem right now... small crack under the threads of the expansion tank... couldn't be bothered with it yet... not overheating, losing coolant very very slowly... faint smell of coolant if i turn on the outside air....