My '91 245 has only let me down two times in 225k miles:

When the original plastic radiator failed (top hose nipple blew off with no warning).

When the crank position sensor wire failed.

Both times I managed to patch it up well enough to limp home without paying for a tow, but it was not pretty.

I would urge you to replace that plastic radiator and hoses (and the crank position sensor) before you even worry about the moderately high water temperature. Don't waste money flushing and putting fresh coolant in that old radiator.

As noted elsewhere, hose the debris out the A/C condenser while you have your radiator out.

High operating temperature only at low speed does sound like fan clutch, but if the fan is noticably stiffer when hot than it is when cold, then it is doing some good. I don't think that they ever "engage" solidly, but I could be wrong on that.

Other possibilities - thermostat may not open fully. You can easily remove it and boil it in a pan of water or run without it for a day to test that theory.

If the car has been run with old antifreeze for extended periods, the water pump impeller blades may have corroded away, reducing water flow. That is common on some cars but not common on Volvos.

If you have to replace the water pump, check this board for tips on how to do it without developing a leak between the water pump and head.

Happy Bricking

Thanks for the responses, guys!

I tried the "poor man's thermo test and the thermo is opening...just a little later than I'd like. I already bought an OEM Volvo 87 degree thermo and have it in the garage...I might replace it, just to be safe. (again...I have never been inside this cooling system - I have no idea what it looks like, but its easy and cheap to replace).

The radiator has tons of bugs, grit and grime crammed in the fins and I tried to get most of it out. For as ratty as this radiator looks, I am surprised it is not leaking out somewhere.

I also found a new 3-row Nissens radiator for this car at a local radiator shop and they want 170 dollars for it...should I buy it and replace the radiator anyways? This IS the original 14 year old radiator and it does look quite questionable. The guys at this radiator shop say that the Nissens units are really good for replacements on Volvos and will definately keep it cooler than the old stock unit. 170 bucks and another hours worth of wirk is cheaper than running my 240 hotter than it should be...is it not?

Thanks,

-Brickboy240

Thermostat poor boy test: Start the cold engine and test the upper rad hose for temperature with your fingertips every 20 seconds or so. When/if the stat opens, the gradual temp rise you have been feeling will change to a rapid, too-hot-to-hold, situation. Go back and forth to check the temp gauge to make sure there's no overheating while this is going on.

If the stat seems good, the fan clutch seems good, and the rad appears clean externally, you may have partially clogged rad tubes. Before lashing out on a new one, here's a possible $10 fix.

Go to a GM dealer and ask for "p/n 12346500 Prestone® Heavy Duty Cooling System Cleaner, 2 part, with neutralizer". This stuff is not offered to the general public at the typical chain stores, as it's pretty potent, and the instructions must be followed closely. There's a GM TSB dealing with the procedure in detail, but simplified instructions are on the package. The GM TSB called for starting off with at least a half tank of gas, putting a dime in the throttle stop to achieve a 2000RPM engine speed, and letting the mix circulate in the running engine (heater on Full) for about two hours. Then drain, refill while adding the neutralizing solution, run again for about ten minutes, drain, flush a couple of times with water, and refill with 50/50 antifreeze.

If this doesn't work, it's probably time for a new rad.


--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, 'my' 94-944 B230FD; plus grocery-getter Dodge minivan, hobbycar 77 MGB, and a few old motorcycles)

I'd suspect it time for a new radiator, but a clean and flush and refill would be a good place to start.
Poorgie

You could very well have 14 years of dirt, weeds and cat hair wedged in the cooling fins of your radiator. Your Volvo radiator is easy to remove. When you hold it up to the light your should be able to see light through it. I would bet yours is restricted.

Use a garden hose to force water from the back of the fins towards the front. Be careful with the amount of pressure and the direction of the flow as it is easy to damage/bend over the cooling fin. After cleaning hold up to the light to see where you need additional work. Straighten any bent fins. you are looking for maximum air flow.

Take the water hose to the back side of the air conditioning condensor and force the crud lodged in it out throught the front.

This exercise may well solve your problem. If not you might want to look at the fan clutch as a source of your high operating temperatures. There is also the possibilty of the radiator being restricted internally. The original Volvo plastic tank radiators are prone to failure because the plastic only lasts so long. Even if yours is not restricted the plastic tanks may be at the end of their useful life.

Randy

replace thermostat. Like... yesterday...

It could be something else, but the thermostat is cheap and easy and most likely. Always rule that out first. And don't let it get so hot... it can and likely will do damage. Aluminum cylinder heads don't like to be overheated.



--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC