Now I'm wondering if I'm overreacting. I just went poking around the engine bay with a mirror and I can't see dried coolant mist on the hoses or on the underside of the thermostat housing, which were replaced this go around and are new. I'm only seeing it on things like the fan shroud and in crevices where I had trouble reaching when I was cleaning things up before. I'm wondering if the coolant stains coming back is simply because they weren't cleaned well enough, as I was only using water and rags to clean up before. It's also possible some spilled coolant in some crevice from the repair job was splashing around. I'll continue to monitor.
-
Well, I'm now pulling my hair out. I got my parts and put everything back together last weekend. I did an initial test drive and everything checked out OK. Great!
Fast forward to today and I saw a characteristic wiggle in the water temp gauge. I opened the hood and sure enough, the fan shroud has the dried coolant mist on it again. Something is STILL leaking in the thermostat housing area. EVERYTHING has been replaced by this point. I don't even know what to do anymore.
Leave a comment:
-
yes, it's about as difficult to remove that pipe as pulling up a shift knob that has never de-mated from the shift lever.Leave a comment:
-
Thanks for the tip, S14. I was actually thinking about that so I ordered a spare gasket for the other end of that rear connecting pipe just in case. I'm not sure if it's worth the effort of getting that little pipe out, though. I gave it a tug and it seems to be in place pretty good. It stayed in when I replaced the thermostat 4 years ago, too, and I'm inclined to not mess with it if it's not leaking, which I don't see any evidence of.
Considering it's never been removed, do you think it would be important to do so now?Leave a comment:
-
On my euro S50 car I had an issue with the pipe at the back of the thermostat housing that is only held together with 0 rings on either end. I had a damaged one on re-assemble and it would suck in air but wouldn't leak so I constantly had air in the system. On the 3rd removal I finally found the little knick and it solved my problems.
Those O-rings should be replaced as they become pretty square in shape with so many heat cycles.Leave a comment:
-
Yeah, I talked to a friend who suggested the same thing.
A new thermostat housing, O-rings, radiator hoses, and fresh coolant is on its way. I'm glad this mystery will finally be behind me.Leave a comment:
-
Consider replacing the thermostat housing itself as well. It's got a rubber seal on the inside that seals against the thermostat. A failing seal might lead to temperature fluctuations by allowing some coolant to bypass the thermostat.Leave a comment:
-
Found coolant leak/temp fluctuation I've been chasing... looking for thoughts
Hello all,
I'm sure no ones remembers, but I've been posting in various threads on M3Forum trying to diagnose a weird coolant temp issue I've been having off and on for about two years. I've had two different shops look at it and I've been doing various suggested troubleshooting measures myself. Pressure tests never revealed a leak and the temperature fluctuations were always too random to isolate the cause. The shops didn't know what was going on, either. I had already replaced the water pump and thermostat, and I later ended up replacing the radiator when it started to leak. The issue persisted.
This summer I noticed the temp fluctuations were getting worse. I also noticed little bits of dried coolant showing up in odd places in the engine bay, as it appeared that coolant was occasionally dripping onto the belts or fan and were flung around the engine bay. But I could not find any dripping while idling in my driveway and pressure tests continued to find nothing (pressure held perfectly). The coolant level was not visibly dropping.
Finally, this weekend, I was poking around the engine bay looking at something else and I noticed significantly more coolant spots than before, and I was able to find a a trail pointing towards the thermostat housing area. I opened the coolant bottle and the level had dropped noticeably. After removing a bunch of stuff, it became obvious my thermostat housing is leaking. This is likely the source of all of my issues, as I now believe I've had a microleak in the thermostat housing seal for years, possibly since I replaced the thermostat itself almost 4 years ago. It's just taken this long for the leak to become significant.
I've removed the housing itself, and the seal does not have any obvious damage. I still do not know exactly why the leak happened. I'm thinking I should go ahead and replace the seal in case there's a microtear or something I can't see.. I figure I should also replace both coolant hoses since they're still original and quite swollen, though that's not related to this problem.
Is there anything else I should consider replacing or look at before I get the parts and put everything back together?
Leave a comment: