Greetings:


My 95 850 GLT station wagon is getting hot! After about 15-20 minutes of hwy driving the temp indicator rises to the red zone! This is my only car for the moment, so your help would be greatly appreciated. I checked all of the hoses, and for some odd reason, only the lower radiator hose is cool-luke warm? The rest of the hoses are somewhat hot to the touch. The car has nice heat, might the thermostat still be partially stuck open? I disconnected the upper hose and the flow seems to be moderate, even when the engine is being accelerated in the 3-3 range, might it be the water pump? But the lower radiator hose is most cooolest, nearer to the radiator, and warmest as the lower radiator hose extends towards the engine block, where might the block be? Is it possible that the radiator could be clogged and or partially blocked, when I squeeze the hoses I do get somewhat of a surge back to the reservoir tank. Again, is it till possible for the thermostat to be partially open to recieve strong heat and over-heat. One other observation that I noticed was that the car could ilde for 35 minutes or so and still not overheat, but once on the hwy and or street driving, the needle sort of jummps up in spurts, and then to the hot zone! Please all experiences and or suggestions would be greatly appreciated! Thank you in advance!

Best Regards,

1995 850 GLT WAGON NON TURBO 20 VALVE A.T. 180,000 PLUS ORIGINAL MILES

Most Volvo thermostats fail in the open position which would give you very little heat.
The water flows into the radiator from the top and out of the bottom back to the engine. So there is a little flow, just not enough to cool the engine when above idle speed. That explains the cooler lower hose.
When flushing the radiator, you should invest in a new radiator very soon, pull both the top and bottom hose and flush it with a garden hose from the top. When putting the hose and clamps back on, make sure they are back in their original position and do not over tighten the clamps.
In the mean time, keep the cabin temp at max and set aside time to replace the radiator. The sooner the better, and flush the whole system to get rid of that stop leak junk.

Klaus
--
The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Thanks! I am preparing to pick up and replace the old radiator. 850's are such a pita to replace their radiators. All of my 740's were wonderful, in that the radiator was right up front minus the extras, also they were all metal, which enabled them to last forever! If I do the quick disconnect/flush of the upper/lower radiator sections., would that help elevate the overheating for the moment until I get my radiator? The lower radiator hose is really cool at the radiator/lower hose connect. It only seems somewhat warm nearest to the lower hose-engine block connect. I am wondering if most of the goop will run out with a garden hose? I shall give it a try, thanks again!

Thanks guys!

I think the thermostat may be stuck closed. The heater doesn't require the thermostat to be open to work but if the stat is stuck open you won't get much heat during highway driving. Flow to heater is from the head via a separate circuit from radiator.

The other (I think likely) possibility is an obstructed radiator as you suggest. I had a quite similar behavior in a car where it would overheat mainly when it was doing some work like taking a long hill. Indeed someone had most likely put something in the radiator of that car because when it was cleaned a great deal of gunk came out.

One more thing to check out, related to overheating after driving a while, is a sticking brake or bad wheel bearing (though that would not explain your lower radiator hose being too cool).

Sorry to hear of the overheating. Start from basics. Have you flushed and replaced the coolant? If the radiator is partly clogged, maybe a flush will clean it out. Any chance you or a previous owned used a stop-leak chemical in the coolant?

Thanks! I have tried to flush it to no avail. I do believe that the previous owner used some stop leak. I found a bottle of Barr's Heavy duty radiator sealer in the tire compartment. So that leads me to believe that the radiator maybe the culprit? Again, the lower hose seems only slightly warm -cool at the radiator/lower hose connection and outwards just somewhat beyond the clamp. All of the other hoses are somewhat hot to the touch! And when I tried to flush it out, the water did go down in the reservoir tank. Initally I had been told by the former owner that the radiator had been leaking, and placed under the impression that it had been replaced! So might the clog be at the lower rad-hose? I get strong heat. Is the lower radiator hose the return hose, whereas the coolant goes from the reservoir down and back up via thermostat back into the radiator and back out of the radiator via the lower hose? My overflow hose from the thermostat housing had only a small stream of water going through it when I was trying to flush it, should the water going through this small hose be more rapid? I have no plumes of white smoke, and or oil coolant in my oil, and my hoses haven't seemed to collapse either.


Best regards

Thanks! I have tried to flush it to no avail. I do believe that the previous owner used some stop leak. I found a bottle of Barr's Heavy duty radiator sealer in the tire compartment. So that leads me to believe that the radiator maybe the culprit? Again, the lower hose seems only slightly warm -cool at the radiator/lower hose connection and outwards just somewhat beyond the clamp. All of the other hoses are somewhat hot to the touch! And when I tried to flush it out, the water did go down in the reservoir tank. Initally I had been told by the former owner that the radiator had been leaking, and placed under the impression that it had been replaced! So might the clog be at the lower rad-hose? I get strong heat. Is the lower radiator hose the return hose, whereas the coolant goes from the reservoir down and back up via thermostat back into the radiator and back out of the radiator via the lower hose? My overflow hose from the thermostat housing had only a small stream of water going through it when I was trying to flush it, should the water going through this small hose be more rapid? I have no plumes of white smoke, and or oil coolant in my oil, and my hoses haven't seemed to collapse either.


Best regards