[RonnieT2]

So far, everyone I've explained my problem to has told me "be happy it's not overheating". I am! But this is confusing the hell out of me...

Recently, my P38 has started showing a much lower reading than normal on the temperature gauge. In the 7 years I've had the car, the temp gauge has always sat dead centre (bar head gasket failure day, but we'll not go there). Now, it just about makes it into the "safe" section of the gauge, sitting on or slightly above the left hand edge of the white operating temperature range.

And I really can't work out why. The only time I've experienced a problem like this before, I'd changed a rad, but there's no reason I can see for the car running cooler. In older cars, I'd think a thermostat was sticking wide open, thus not allowing heat to build up, but I'm lost in this case!

As extra confusion, the car pumps out lots of lovely heat as it gets up to temperature, but on longer runs I have to put the aircon either off or up to HI to get anything approaching warmth. And there seems to be more condensation around the boot that ever before too. I don't know if any of these are related, but any suggestions are more than welcome

 

[munichp38a]

Hi and welcome to the board!

Why shouldn't your thermostat be faulty in this case, too?

Sigi

 

[RonnieT2]

Why shouldn't your thermostat be faulty in this case, too?

Thanks for the welcome - I was here many years ago and forgot all my login details*, so had to re-register this morning!

My friendly mechanic told me my thermostat "looks OK". I'm more used to neat little brass/metal things a couple of inches wide which can be removed and boiled up in a saucepan with a thermometer to see if they're working. The one on the P38 looks like the brain of Orac, with about 5 pipes going into it and I really wouldn't know where to start! Hence the call for help




* This can only be a good thing - it's means I've had about 4 years of problem free motoring!

 

[munichp38a]

The thermostat is in there, you can take the complete housing out and look at it, if it's stuck open you'll see it even without boiling.

Did your mechanic take it out and look into it?

Your coolant level is ok?

Sigi

 

[RonnieT2]

Did your mechanic take it out and look into it?

Let me answer your question with a question munich... is it difficult to take the thermostat out ?

If the answer is yes, I would say he probably didn't take it out
If the answer is no, I would say he still probably didn't take it out

As I say, all I'm getting is "you should be glad it's running cool". And that's from 3 specialists !

 

[viperover]

Temp sender unit failing, I would replace either way as its a known problem aerea.
Also check connectionis good, up to 97 it sits on the manifold, 97 onwards its sits on the pipe fitting the top rad hose is connected too.

 

[munichp38a]

I didn't have to take mine out yet, but according to RAVE it doesn't seem to complicated: undo the clamps on the hoses, "Release 2 clips securing thermostat to housing
radiator cowl and remove thermostat housing." (cited from RAVE) and take the thermostat out.

You'll have to drain and refill the coolant (use the correct antifreeze!), though.

When you're refilling, be sure to undo the small hose on top of the rad (don't break the small nipple!), blow through it and reattach it, otherwise you'll suddenly have an overheating engine because there's air in the cooling system...

This description is for the V8 engine, could you please add your exact model description to your sig and your location to your profile?

Sigi

 

[munichp38a]

Temp sender unit failing, I would replace either way as its a known problem aerea.
Also check connectionis good, up to 97 it sits on the manifold, 97 onwards its sits on the pipe fitting the top rad hose is connected too.

I tought of that, too, but the OP also says the heater doesn't work very well.

Wouldn't that point to low coolant temp, as the HEVAC has it's own temperature sensor at the heater core pipes?

Sigi

 

[kyle h.]

Does your engine fan spin all the time? I am experiencing similar problems and I've noticed my fan clutch has failed.

 

[viperover]

Does your engine fan spin all the time? I am experiencing similar problems and I've noticed my fan clutch has failed.

was gonna mention this as a possible but now that you say heater doesnt get hot then thermostat is very likely to be stuck open, not common but better than being stuck closed and over heating.

best replace thermostat as running cool can cause piston seizure, its when the piston expands but the block doesnt