JJs Project Thread - 240 GL Estate

[BicycleBoy]

Originally Posted by Problemchild1976

Oooh - what “actuates” the clutch?

Coiled spring on the front of the clutch: When air temperature passing through the radiator exceeds a level (be it high external air temperature or an overheating radiator) the coil expands, turns internal gubbins which opens fluid ways and the thermoviscous clutch engages, causing fan to turn at crank speed.

[Problemchild1976]

Originally Posted by BicycleBoy

Coiled spring on the front of the clutch: When air temperature passing through the radiator exceeds a level (be it high external air temperature or an overheating radiator) the coil expands, turns internal gubbins which opens fluid ways and the thermoviscous clutch engages, causing fan to turn at crank speed.

Mega - will test resistance at temp tomorrow

JJ

[Othen]

Originally Posted by Problemchild1976

So been having a few “overheating” issues in this warm weather - normally after a short run (normal temps) then a pootle back and it goes up close to the red

mix this with my 20mpg - I think I’m running rich or the timing is out

Can’t get the dizzy to move atm as it’s corroded to the block so putting some penetrating fluid on it from time to time.

But when I am flooring it on the dual carriageway it’s perfectly normal

And this Evening only rose a little once I came off the 70mph into the side roads

Thoughts?

JJ

I'd suggest the first thing to do would be to establish whether the engine is really running hot, or whether the gauge is reading high. The easiest way to check is with an IR thermometer like this:



... they aren't expensive (maybe £20) and are useful for lots of other things. Point it at the thermostat housing when the engine is hot - it should be 90c or there about. It is always a good idea to make sure one is fixing the right problem :-).

Then then check the potential difference at the instruments - it should be 10v. If the motor car isn't running hot (unlikely if the fan isn't coming on) then perhaps the gauge is heading high (does the fuel gauge read high at the same time?) - the culprit may well be the 10v voltage stabiliser in the instrument binnacle. I replaced the the very quaint mechanical type device in mine:



... (although yours is a later motor car and may have something more modern) with a solid state stabiliser (cost about a tenner and a really easy job:



That solved the issue completely.

If that isn't the problem we can start looking for real overheating problems elsewhere (but you seem to have already fixed all the likely culprits already).

I wouldn't have thought running hot (if it is) would lead to high fuel consumption (probably the opposite). That needs a bit more investigation. Start off by making sure the basic things are right, so check the compression across the cylinders (easy and cheap to do) and the ignition timing. You said your distributor had seized (common problem) but you can still check it with a strobe - if it is incorrect we can start thinking of ways to get it moving.

Another lovely day in paradise.

Alan

PS. You may need a 'Special Volvo B21a Distributor Adjuster' like this one to free it (after a few more doses of DP90):

https://www.volvoforums.org.uk/showp...postcount=1388

[foggyjames]

Spot-on advice from Othen there.

It's worth pointing out as a general note that, with modern ignition systems, turning the dizzy will often do almost nothing (until it's turned so far that the rotor tip is aligned with the wrong cap contact, anyway), as the timing is entirely controlled by the computer. The 240 is an exception, in that the timing pickup sensor is built into the dizzy, so that will adjust the timing, but turning the dizzy essentially does nothing on a car with, for example, a flywheel pickup (such as a 940, or 850). I agree that if the dizzy is corroded up and this is a new problem, it's not going to be that. Possibly worth checking the cam (and aux belt) timing in case it's jumped a tooth.

Running lean certainly will increase engine temperature, but I think it's vanishingly unlikely to be the cause here, especially as it's doing it worst when pottering.

I'd start with Othen's advice and take it from there.

cheers

James

[Othen]

Originally Posted by foggyjames

Spot-on advice from Othen there.

It's worth pointing out as a general note that, with modern ignition systems, turning the dizzy will often do almost nothing (until it's turned so far that the rotor tip is aligned with the wrong cap contact, anyway), as the timing is entirely controlled by the computer. The 240 is an exception, in that the timing pickup sensor is built into the dizzy, so that will adjust the timing, but turning the dizzy essentially does nothing on a car with, for example, a flywheel pickup (such as a 940, or 850). I agree that if the dizzy is corroded up and this is a new problem, it's not going to be that. Possibly worth checking the cam (and aux belt) timing in case it's jumped a tooth.

Running lean certainly will increase engine temperature, but I think it's vanishingly unlikely to be the cause here, especially as it's doing it worst when pottering.

I'd start with Othen's advice and take it from there.

cheers

James

That is a good point about the cam or auxiliary shaft sprocket James (whichever drives the distributor on the OP's engine). Each tooth must be about 6 degrees (I'm guessing about 60 teeth, although I've never counted them), but that will be doubled at the crankshaft. If the timing is 12 degrees out that would certainly show up straight away with a strobe test.

If the OP hasn't done it already then a new timing belt would be a good idea anyway, I bought a new Gates belt just a few weeks ago for about a tenner and it is a really easy job to swap.

[Problemchild1976]

Originally Posted by BicycleBoy

Coiled spring on the front of the clutch: When air temperature passing through the radiator exceeds a level (be it high external air temperature or an overheating radiator) the coil expands, turns internal gubbins which opens fluid ways and the thermoviscous clutch engages, causing fan to turn at crank speed.

So when the car is up to temp on the gauge I can stop the fan and spin it backwards

New viscous fan clutch on the way

JJ

[Problemchild1976]

So this evening I refreshed the black strips under the windows

I know these are decals - and maybe getting new ones would be better but I just masked off and sprayed





Used some left over stone chip matte black

Turned out all right I think



JJ

[Othen]

Originally Posted by Problemchild1976

So when the car is up to temp on the gauge I can stop the fan and spin it backwards

New viscous fan clutch on the way

JJ

I don’t have this system on my motor car, but surely the clutch would only engage when the engine is about to overheat? I’m guessing you could test the system with a hot air gun (or a hairdryer) without the motor even running.

Alan

[Problemchild1976]

Originally Posted by Othen

I don’t have this system on my motor car, but surely the clutch would only engage when the engine is about to overheat? I’m guessing you could test the system with a hot air gun (or a hairdryer) without the motor even running.

Alan

I’d assume that any temp past the standard operating temp the bi-metallic strip should activate and allow the fan to spin much more firmly to increase airflow

It was pretty warm when I tested it 👍🏻

It’s only £30 for a new one - rules out another issue

JJ

[Moomoo]

Originally Posted by Problemchild1976

So this evening I refreshed the black strips under the windows

I know these are decals - and maybe getting new ones would be better but I just masked off and sprayed





Used some left over stone chip matte black

Turned out all right I think





JJ

It’s turned out successfully on my 245 GL , why not yours?😎👍