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Does this look like a bad thermostat?
Do they often become sticky if used, removed from car, cleaned, and kept on a shelf?
I changed out a working thermostat after using it for only a few weeks, because I wanted to change to another temperature-rated t'stat. That was fine.
I saved the unwanted thermostat after rinsing it off. A couple months later I installed it into another 240 ('90) that had overheating problems. With the "new-used" t'stat, this car still overheats. Needle goes high after a couple minutes drive - it starts up from the bottom and just keeps going, never stopping in the middle. Run the heater + fan, and it settles at or slightly above the middle, now you can drive all day.
If you remove the reservoir cap when needle is high, coolant spurts out the top of the plastic bottle. So it's not just an electrical wrong reading on the gauge.
I've covered everything else I can think of on this car - I changed out the radiator so I'm pretty certain the radiator is not clogged. I bypassed the temp compensator board and replaced the little voltage regulator on the instrument cluster.
The only other thing I can think of is water pump impeller blades corroded away due to prev. mechanic using tap water?
Considering the cost + time of the parts + work, I think I'll put in a NEW thermostat this weekend - but what do you think?
--
Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).
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Maybe a bad fan clutch? I would take it for a long run on the open highway, without the heater running. The steady airflow would compensate for a bad fan clutch, if it runs cool, you have your answer. If it doesn't, change the T-stat.
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Bruce S. near D.C.
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Still, it sounds like the tstat is stuck closed. The only way to check it out is to remove it and put it in boiling water to see if it opens.
Klaus
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(V♂LV♂s 1975 164, 1995 854T, 1998 V70R)
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Putting a used thermostat on the shelf is OK. But, before putting it in the car, try cleaning it in boiling water to make sure it is working. Antifreeze is very sticky when it dries and it will take a while to "unstick" itself.
Using tap water will add unwanted minerals which will stick to the metal parts and not make the innards happy. Especially soft metals, like copper and aluminum. It will not cause the water pump to wear out.
If the heater fan cools the engine, why isn't the engine fan doing its job? Is the Engine Temp Sensor working correctly? If the top hose is very hot, you may have a blockage in the radiator core,
Klaus
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(V♂LV♂s 1975 164, 1995 854T, 1998 V70R)
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Thanks, Klaus. I know you speak from good experience.
Klaus wrote,
"If the heater fan cools the engine, why isn't the engine fan doing its job? Is the Engine Temp Sensor working correctly? If the top hose is very hot, you may have a blockage in the radiator core"
Good question. In this cold weather, car could have no engine fan and would be fine. Here in New England the weather is cold enough, my other car (daily driver) with e-fan only never needs the fan if moving at least 15 mph. Even stopped at a light, it takes a long time for fan to be needed. Light changes first!
Radiator tested clear before putting it in. I tested with hose as I saw written up, turning radiator (vertical, with connection openings at top and bottom) and blocking certain openings. Water went through just fine. Who knows, maybe it's blocked now! I did clean the outside too, so the air can get through.
Or maybe thermostat is sticking now.
Never heard of pump impellers being mostly gone? I saw it posted here somewhere. Supposedly due to corrosion. Not all brands made from the same materials.
--
Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).
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Water will ALWAYS spurt out if you remove the cap, even at normal operating temp.
Remove the t'stat entirely and see if there's still a problem.
Unless there's no coolant added, tap water won't corrode anything.
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Doesn't spurt in our other 240s. Just a slight "pfffftt" of pressure release when you turn the cap a quarter turn or so - that's all. I'm going to test that on my daily driver today after it gets fully warmed up, with engine running - just to verify.
Anyway, to repose my original questions,
1) Any other experiences with known-good used t'stats going bad on the shelf?
2) Does this sound like a t'stat sticking closed to you?
--
Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).
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I don't know of any issues from a T-Stat sitting on the shelf, but if it's older than 4 years, it merits replacing (just to be on the safe side). The date stamp is usually on the bottom of the thermostat, facing into the engine on the lowest disc below the spring.
The original OEM supplier to Volvo when our cars were built was Vernat/Caloristat and they still make a great thermostat (mail order from FCP Groton for $9). I've installed a lot of them in my friends cars, and only had one that was a bit sticky to start with (but it works fine now after a few days of use). All of the others have worked great from day one.
The current thermostat supplier to Volvo is Wahler, and they make terrible thermostats. The Brass metal they use in the thermostat housing is way to soft, and tends to fatigue and break. Most often, it will break one of the two spring tensioned legs at the bottom, and cause the thermostat to open wide and stay open (causing a very long warmup). However, on the rare case they the Brass top fails, it will lock up tight in the closed position and cause an immediate overheat. I've had one friend who had a 3 year old Wahler fail in the closed position, and before she noticed the temp gauge it was too late. It had risen above the overheat marks and the engine head had warped (causing the head gasket to loose compression). She took the car to a shop where she had to have the head resurfaced/planed to restore compression.
If anybody who works for Wahler is reading this post, -I've got a bucket full of broken/failed Wahler thermostats that I've taken out of my friends cars (from tuneups when they bought them). Compare this with one of my friends bought an '89 Turbo 740 that still had the original factory installed Caloristat, which still worked fine.
God bless,
Fitz Fitzgerald.
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'87 Blue 240 Wagon, 268k miles.
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