So my 1990 240 has been overheating the past few days and I took it into my regular Volvo mechanic to have it looked at. When I would pop the hood after driving a short while I was greeted with billowing steam clouds and a hissing noise that could be identified as some type of leak. In the past few days, I have had the thermostat replaced, temp sender unit replaced, and I have had a loose bolt that seemed to be causing a leak tightened. Now when I drive the car it takes much longer to heat up but it still overheats. Now when I open the hood less steam comes from the engine. My mechanic had thrown around the idea that it might be a problem with the heater core? Any suggestions....please....because I know these are the types of recurring problems that can cause one to get rid of a car. Thanks.
--
1990 244DL - K&N, airbox mod, 2 15' JLs, Brickstylz body kit, underbody neon (2.5' straight pipe exhaust system, performace cam to come!!!) all at 255K+ miles. 1998 S70 GLT - mom and dad's car. If only....

I agree that your Volvo mechanic is reaching when he thinks about the heater core -- that's inside the car, after all. If you're getting problems with that, you'd know it as you sat in the driver's seat -- experience speaking.

Start the car in your driveway, let it warm up, and look everywhere water could leak from. I've just diagnosed the problem on my son's 1982 240, which sounded similar -- it would run low on water, resulting in, as he put it "aggressive boiling over." It seems the plastic "overflow" tank through which you fill the radiator has developed a weak spot. It doesn't leak visibly when cold, but it begins to leak from under the tank as the motor warms up and pressure in the system increases. It took a while to find, as it was dripping underneath, onto the bracket that holds it, and then sneaking down the fender liner. There's a well in the middle of the top of the tank, with a matching upside-down well underneath, and it's leaking from there -- I suspect the plastic has cracked where it was heat welded together at the factory. I'll be driving in rubber stoppers top and bottom with "Goop" adhesive smeared all over them, and see if that fixes it. Cheaper than buying one, if it works.

Bill, I'd start looking for a replacement tank, ought to be easy to find in the boneyard. Chances are after 20 years the plastic has just become brittle all over and just the weakest spot let go first.

My '88 245 would overheat about 3 miles or so after warming up, and steam would pour out from under the hood. Several times I parked it in the driveway and opened the hood, engine running, and tried to figure out where the leak was. Nada. Could not make it leak when parked. I took to carrying 2 gallons of water with me so I could make it to work (40 mile commute). Finally one day I got 15 miles from home and had already put in 2 gallons - still couldn't find the leak - and I threw in the towel. Pulled into the dealer, rented a car for a day, and got the call a couple hours later that the radiator had several leaks. Why I couldn't make that stinker leak in the driveway is beyond me. What really fried me was that the replacement rad cost me about $350... nearly 3x what the aftermarket charges. (Shovlfxr take note... the rad you got with Rumblegutz was only 2 years old!)

One other thing to check is the heater hose behind the engine - short and a bear to get at. Feel it to check for wetness which might indicate a leak.

Consider going to a radiator shop and having your system checked there.

Parker240,

Since you have billowing steam coming out of your engine area, we can safely infer that you definitely have a cooling problem and not just a temp compensation board "false indicator" problem in the dash. ;)

I don't know about the heater core issue that the mechanic is pointing to, I would think not. Some on the board have suggested in the past that if the temp goes up, open up your heater control to full hot and see if that helps bring the temp down. This is not a fix, of course, simply a diagnostic.

If it were my car, I would check the condition of the radiator, now that you've already replaced the thermostat. Use a garden hose and with the engine *off* ;) spray water through the fins of the radiator from the engine side out. This will clean the fins and allow much more air to flow through the radiator. This will greatly improve the efficiency of the radiator, if it has become plugged with bugs, sand, dirt, and miscellaneous *crap* over the years.

Also, what is the condition of the anti-freeze? It should be a 50/50 mix with distilled water (I believe - please someone correct me if I'm mistaken on that) and that will carry the most heat away from the engine to the radiator.

Is the radiator plugged? Is the cooling system holding pressure?

If the radiator is plugged, obviously it cannot radiate the heat from the coolant to the air. Check also to see if the system is holding proper pressure. The coolant will boil at a lower temp if it is not properly pressurized.

Lastly, is the fan pulling a good amount of air? I don't know much about cooling fan clutches so I can't comment from experience on this, but others on the board have mentioned that the clutch can fail or wear out and not pull the necessary air through the radiator for proper cooling.

If all these things check out ok, you might try to determine if there is some reason why your engine is running so hot... usually this happens with a lean mixture or too hot a plug range... Also, is your exhaust system working well and no plugged cat?

Just some ideas, I hope you find it and report back so that we can all learn from it.

Good Luck!

Regards,

TomD
'86 240
'93 240

Who is your mechanic? If he is "throwing around" ideas about the heater core, it doesn't sound like he knows exactly what he is talking about. The heater core would have nothing to do with billowing clouds of steam coming from under the hood.

What type of driving does it overheat in? Stop and go traffic? Highway? Going up a long hill?

How old is your radiator? Maybe it's time to get a new one, they don't last forever. When it clogs up, it will cause problems like you describe. Is the hissing noise and steam coming from the cap on the coolant overflow tank?

If you replace the radiator, it is probably a good idea to change the thermostat again.

You may also want to check the operation of the fan. It is driven by the engine, through a clutch mechanism. When this clutch gets hot air from the radiator, then it makes the fan spin with the engine. You will hear it roaring, you probably know what I mean. This is the roaring that you always hear for a few seconds when you first start up your car and drive away. One way to check it is to warm up the car, then put it in neutral and hold the engine at maybe 2000 rpm for a while. You should hear the fan roaring on and off.

If you don't hear the roar, it could be the fan clutch, or it could be the radiator is clogged. When the radiator gets clogged, it doesn't pass enough heat to the fan clutch to activate it.

Good luck,
Greg

What's your question?


I had a 240 that had a over heating problem. It drove me nuts. I could never figure out what it was. I replaced everything and checked everything. When the gauge said it was hot I checked the hoses and they didn't seem abnormal. Finally out of frustration I smacked the dash. Voila, problem fixed. Turns out it was a faulty gauge.