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[ians]

Right. I’m going to make a determined effort to sort out the overheating issue on my 3.0.

Thanks to TB and RichardA, what I know so far is that the instrument panel is configured correctly and that the fan system, switches, relays etc all come on when they should.

The symptoms show up in hot weather, especially in slow traffic, but it also runs hotter than it should at speed on the motorway.  In traffic I have had the red light come on.  On these 2 occassions I have stopped straight away and get the impression that the temp then drops quite quickly – on one occassion I stopped at traffic lights, turned ignition off, on again when lights went green and temp had dropped back to 97 or so from 100+
The stat appears to be closed from cold and temp rapidly climbs to 92 degree level just as it should.  It stays there for a bit and then starts to rise again.   Noticable most of the time, but only a real issue in very warm weather when it will start to push 100.   Although I know for sure the fans come on, they don’t have the effect of rapidly reducing temp as they should.

My suspects:
-      Radiator lost efficiency – this is my biggest suspect, backed up by the fans not having the effect they should.
-      Stat opening but not fully
-      Water pump failing

I am due to change cambelt (and water pump) soon and am considering removing the rad and reverse flushing while I’m at it (or should I bite the bullet and replace it?).   I’m considering replacing the stat too to illiminate that but really would rather not – I don’t honestly think that’s the problem, and I know its a pain to do.   I can’t see how the coolant pump could fail as its a relatively simple thing, but that will get changed with the belt.  

Any thoughts, suggestions appreciated
Is it worth doing a flush with Forte or the like first?  (I have flushed umteen times with water and it was running crystal clear)

Cheers,
Ian

[TheBoy]

forte flush it.

then check rad for cold spots...

[cem_devecioglu]

Right. I’m going to make a determined effort to sort out the overheating issue on my 3.0.

Thanks to TB and RichardA, what I know so far is that the instrument panel is configured correctly and that the fan system, switches, relays etc all come on when they should.

The symptoms show up in hot weather, especially in slow traffic, but it also runs hotter than it should at speed on the motorway.  In traffic I have had the red light come on.  On these 2 occassions I have stopped straight away and get the impression that the temp then drops quite quickly – on one occassion I stopped at traffic lights, turned ignition off, on again when lights went green and temp had dropped back to 97 or so from 100+
The stat appears to be closed from cold and temp rapidly climbs to 92 degree level just as it should.  It stays there for a bit and then starts to rise again.   Noticable most of the time, but only a real issue in very warm weather when it will start to push 100.   Although I know for sure the fans come on, they don’t have the effect of rapidly reducing temp as they should.

My suspects:
-      Radiator lost efficiency – this is my biggest suspect, backed up by the fans not having the effect they should.
-      Stat opening but not fully-      Water pump failing

I am due to change cambelt (and water pump) soon and am considering removing the rad and reverse flushing while I’m at it (or should I bite the bullet and replace it?).   I’m considering replacing the stat too to illiminate that but really would rather not – I don’t honestly think that’s the problem, and I know its a pain to do.   I can’t see how the coolant pump could fail as its a relatively simple thing, but that will get changed with the belt.  

Any thoughts, suggestions appreciated
Is it worth doing a flush with Forte or the like first?  (I have flushed umteen times with water and it was running crystal clear)

Cheers,
Ian

My idea is the first two ..But before flushing the rad is really good idea..And I would also try a new stat..

[Bandit127]

I do injection moulding for a living and regularly use infrared thermometers. They have dramatically come down in price recently.

A bloke I was talking to today (in the smoking shed) was on about mechanics regularly using them.

e.g....
Finding out which pot is misfiring by measuring exhaust manifold temp.
Checking cooling systems for cold spots/airlocks....

£30 from Maplins
http://www.maplin.co.uk/Module.aspx?ModuleNo=46033

Fleabay probably cheaper...

[feeutfo]

I do injection moulding for a living and regularly use infrared thermometers. They have dramatically come down in price recently.

A bloke I was talking to today (in the smoking shed) was on about mechanics regularly using them.

e.g....
Finding out which pot is misfiring by measuring exhaust manifold temp.
Checking cooling systems for cold spots/airlocks....

£30 from Maplins
http://www.maplin.co.uk/Module.aspx?ModuleNo=46033

Fleabay probably cheaper...

My mech had one similar, used it to check the atf sump was up to temp when checking the level.
Seemed a handy gadget. Esp for this job i guess?

Ians. Do you know the history of the car? Specifically if its likely to have a stop leak product in the system? What year is the car? James v6 cdx has mentioned a core plug leak issue in cylinder head seemingly affecting 98 models, much easier option to bung a bottle or 2 (hopefully not, 1 bottle per system) of bars in than remove the head to fix it or where ever the leak is, or been run on tap water for a time? I confess i did this for a time on my old car as it was leaking in the v almost as quick as could poor it in. Probably not by yourself, but if the car had a leak as some point..? Just a couple of thoughts.

What else could cause the rad to block?

I had always thought the water pump was a bearing issue?

Ps shout if you need a hand.

[Entwood]

I don't know if this is any good or not, but a mate of mine had a similar sort problem on a classic Ford Zephyr, and as parts are difficult to get/have to be made he was getting very concerned. Someone in the pub suggested he contact the local fire brigade and ask if they had a "heat seeking camera", he did and for a suitable donation to a charity they ran the camera whilst pointing it around the running engine ... very quickly proved a restricted radiator.... so he had that recored and everything went back to how it should be.

Just a thought

[Andy B]

I don't know if this is any good or not, but a mate of mine had a similar sort problem on a classic Ford Zephyr, and as parts are difficult to get/have to be made he was getting very concerned. Someone in the pub suggested he contact the local fire brigade and ask if they had a "heat seeking camera", he did and for a suitable donation to a charity they ran the camera whilst pointing it around the running engine ... very quickly proved a restricted radiator.... so he had that recored and everything went back to how it should be.

Just a thought

TIC/Thermal Imaging Camara. We used to have them at sea.