Overheating - 1997 850 GLT

DavidB · Post by **DavidB** » 02 Sep 2019, 19:03

So I feel like a complete moron. My wife had been driving our 850 and the radiator light kept coming on so I just kept adding fluid to it for like the last 3-4 months. I didn't know that mixing different kinds of radiator fluid was such a problem. As soon as she took it to emissions suddenly the AC stopped working. (Don't know if that matters but it's worth mentioning I guess)
I started driving the vehicle and took it across town to work and the second or third day I did that it overheated pretty badly which I didn't realize until I got to work.
I got the thermostat replaced ... And just now I flushed it out as best I could and tried to refill it.
I only found the bleeder valve on the front left side underneath the radiator so I bled it out and then ran the hose into it and ran it with the hose running into the overflow tank up top. Did that until the water came out clear for a while. The radiator was running so I assumed it circulated all the way through. Problem was using that bleeder valve I was only able to get about 3/4 of a gallon to drain out before I tried to refill it.. so I put about half a container of prestone concentrate in there (.5~ gallons) but as I'm trying to test drive it I only got about two stops down the highway before it started getting too hot again so I pulled off.... now I'm sitting on the side of the road waiting for it to cool down before I try to drive it back home....
So if anyone has any thoughts on what my next step should be I would greatly appreciate it...
(I think I can borrow my mom's car for some of this week to get to work but that's not a sustainable thing and I really can't afford to go to a mechanic right now.... unless people are pretty sure that's the best bet then I guess I can make it work but....)
Anyway, thanks for any help and support.

David

dj_v70 · Post by **dj_v70** » 02 Sep 2019, 20:02

Radiator light = low on coolant (ie. leak)

You suggested a leak due to the radiator light coming on, but then you don't suggest that you fixed the leak. You mentioned thermostat replacement, but what about the leak? Does the radiator light always come on before overheating?

Post by **Ozark Lee** » 02 Sep 2019, 20:05

The radiator is pretty much self bleeding through the overflow tank. I just fill the tank until it won't take anymore. If you fill it to the line it will need to be topped off again (less than a quart) in a day or two.

If it is full and still overheating, and you have replaced the thermostat then you may have a bad water pump. Usually a water pump leaks before it quits pumping water but I have seen the impeller break off on them.

If the pump is circulating and you are indeed overheating, particularly if you have overheated badly before, then you may have blown a head gasket. That turns into a major project.

...Lee

Post by **Chuck W** » 03 Sep 2019, 06:36

Is it leaking coolant onto the ground?
Is it blowing white smoke?
Is the radiator fan coming on?

Sounds like you have an external leak (hose, etc) that was never addressed, and now you've overheated it a few times. If it wasn't a headgasket initially, it probably is now.

FIRST, find where that coolant is leaking from. It has to be leaving puddles on the ground.

DavidB · Post by **DavidB** » 04 Sep 2019, 11:35

So the best I can tell the coolant was leaking out of the overflow tank at the top. Pretty consistently so I kept filling it. It could be a leak somewhere else but I never really looked. It was the one time I didn't notice and let it overheat and I hadn't filled it that seems to have killed the water pump....
....
So my thinking now is heat it up to temperature, figure out where the leak, is if I can and hope it's not the head gasket... and I'll need to fix the leak first before I worry about the water pump but I have a feeling this is going to be a bigger pain than I'd like it to be...
..... I'm sure there's a lot more info I need to share for you all to help me but I do have one question in addition: for someone without much in the way of decent tools how hard is it going to be for me to replace the water pump?

Post by **erikv11** » 04 Sep 2019, 12:02

Replacing the water pump involves removing the timing belt. The timing belt is a vital, crux piece of this engine, you want to be careful if you go in there. You don't need fancy tools but you need just a couple specialized ones, here is a video 15 minutes in length that explains it very clearly:

It is very common for the cap to stop functioning properly, leading to coolant leaking out the top of the reservoir. Can you get another cap from a junkyard?

However as stated this may well be a larger problem now, like a bad head gasket which would mean end of life or $500 - $1000 to fix.

DavidB · Post by **DavidB** » 04 Sep 2019, 12:14

Watched Robert DIY's video on YouTube about Volvo's overheating and he mentioned the coolant bubbling over the top might be a symptom of gas is getting into the oil if the head gasket is blown. I didn't notice any missed colored oil per se but I did see that the dipstick had popped out about an inch for no apparent reason. Plus we did start having issues with the car starting but that was after I had poured some water on the engine to cool it off and I think I got some on the spark plugs so.... FML....

Post by **erikv11** » 04 Sep 2019, 12:49

Yes about the head gasket and bubbling over but your posts seem to say it was already bubbling over for several days before it ever overheated? It is super common for the caps to wear out, they basically all do, however it is extremely unlikely for a head gasket to just blow unless the engine overheats. Even a failed water pump is more common than a head gasket issue. Probably the initial bubbling had nothing at all to do with head gasket problems, although the car may have them now. These engines do not handle overheating well.

You won't find coolant in the oil with every bad head gasket, or oil in the coolant, those are common misunderstandings. The head gasket separates three chambers: coolant, oil, and combustion. A head gasket leak can involve any two chambers or all three chambers, and the leak(s) can be in one direction only or in both directions. So there are a whole bunch of different possibilities.

In your shoes I would try to cheaply understand if there is a simple problem (bad cap or bad water pump seem most likely so far) or a complicated and expensive one (blown head gasket).

Post by **ZionXIX** » 04 Sep 2019, 13:33

I recently had overheating issues but it was due to a failing temperature sensor