coolant disaster w/Volvo 850 GLT

[stringsattached]

My sister's boyfriend has a 1993 Volvo 850 GLT (2.4L Inline 5) with about 150,000 miles on it. He just got this one, so he has no idea what kind of maintenance was done on this car in the past, if any.

He told me the other day that since he got the car, he has never been able to get any heat from the vents (I suspect plugged heater core). He then told me that while he was driving last week, his engine started overheating, so he pulled over to stop, popped the hood, and discovered that he was WAY low on coolant. He topped it up, and his car has been consistently overheating ever since.

While I gleefully enjoy his misery, and would like to see him die in a fire, I would rather not have the car explode while my little sister is in it. My first recommendation to him was to have a chemical flush done, and see if that took care of the problem. Now I'm not so sure.

My concern was that if he did this, he might then flush out all the crap holding his cooling system together and spring a leak or ten. I'm looking for any advice from people who have had experience dealing with extremely neglected cooling systems, and more specifically, the cooling system on this engine. Thanks.

 

[Ray H]

I wonder if the thermostat's stuck. Since there's a chance, no matter how remote, that the guy could end up your brother-in-law, advise him to take his car to a cooling system shop. That lets you off the hook without alienating him (and your little sister by extension). If the guy tells you to your face you're an idiot, remain expressionless and smile inwardly. You just won, bigtime.

 

[wpwren]

Have your sisters' boyfriend get the thermostat replaced as Ray H suggested. Get it flushed too for that matter because if it isn't leaking now then it most likely won't from flushing it. Something else to consider at the mileage and while he's at it, changing the coolant temperature sensor. It sits right beneath the tstat housing.

At the stated mileage and if it's original I'd have to think your little sister will get stuck some where eventually. The car will start cold but then stall as it comes up to temp and then won't start until it sits for a while...or longer. Just a good idea to do both...at that mileage if the CTS is original

 

[MC5W20]

There are so many things that could cause this. It is difficult to tell without personally looking at it. In my experience though, when the cooling system is full and it overheats then the problem usually turn out to be a bad radiator due to cooling system neglect (plugged tubes). Also, if it is original water pump that could also be bad.

 

[Ken2]

The Volvo in-line 5 has a plastic pressure coolant tank. The thermostat for the normally aspirated engine is 90°C, and 87°C for the turbo engine. To change the thermostat, a long-shank T-40 Torx bit is needed...don't try it with a short-shank bit; you'll strip the head of the bolt. The engine holds 2 gallons of coolant, so one gallon of antifreeze plus water is just right.

So...I'd drain and flush the existing coolant. If the cheezy plastic petcock is already broken off the bottom of the radiator, just pull the lower radiator hose. There is a block drain petcock behind the block just on the passenger side of center. I prefer to fill the system through the upper radiator hose...works faster and less air trapped than through the plastic tank. If it doesn't have the newer green tank cap, get one. The old gray caps tend to crack. I'd use a heavy duty radiator cleanser to flush the system. If there is a control valve on the line to the heater core, be sure it actually is opening when the cabin control is turned.

Rinse very well, add a gallon of antifreeze (I use Zerex G-05), install the new thermostat and new pressure cap, and see how it works.

Changing the water pump is quite a job. The timing belt is due at 70,000 miles or 5 years, whichever comes first. At the second timing belt the water pump and all idler pulleys should be renewed, as well as the accessory drive belt. This is an interference engine...if the timing belt brakes, the valves and pistons hit, and you scrap this old car. A shop can test for a cracked head. If it is cracked, try a sealant. It is not worth having a shop change the head on this old car.


Ken

 

[stringsattached]

Thanks for the comments everyone (especially Ken 2, wow, I couldn't have asked for more than that!), I talked to him today, and here's the plan of attack:
1) He will be getting it flushed (he was leaning towards chemical, but still hadn't decided for sure) by a shop sometime very soon.
2) If all is well, he is going to then leave it alone. If not, we replace thermostat.
3) If all is still not well, me/friends put the car on stands and poke around until we hopefully find something wrong.
4) If we still can't cure it, panic/drinking/fix something easier to regain DIYer confidence.

We popped the hood today, and the little plastic pressure coolant tank looked great! I guess I was expecting something that looked like an aquarium after all the neglect. All the hoses looked pretty good too. Also, the heater vents now blow zillion degree air like there's no tomorrow (before they barely worked at all). No odd noises when driving (like water pump failure), so I'm seriously starting to suspect system build-up, and/or thermostat.

Anyway, weather is warming up, and the overheating problems will almost certainly just get worse from here, so I hope our plan does the trick. I'll let you all know how it turns out.