Overheating 3200

[Skid1769]

Afternoon Gents,

I seem to be having few problems lately, fix one and another pops up.
Driving down the motorway today the car started to overheat, noticed the vents were blowing cold. It is not cold today so there is no issue of the pipes being frozen. Pulled over onto the hard shoulder, opened up the bonnet, gave the radiator hoses a good squeeze but could feel no coolant in them, eventually the level in the expansion tank dropped and when I started the car the temperature immediately dropped to its normal running temperature. Got going again, with hot air coming out the vent, and jus made it off the M4, about 4 miles when it started to overheat again, no heat coming from the vents. Stopped the car, had a good old squeeze of the water pipes but yet again, evidence of nothing again in them. Eventually started to feel fluid in them, started the engine and the temperature eventually dropped and made a quick dash for home. There was heat coming out of the events and the temp was normal until I arrived home. So, I am thinking a defective thermostat, would you agree???

Your help as always, is appreciated.

Kind Regards

Stuart

 

[dem maser]

Does sound like a thermostat issue. I never had any overheating issues with mine but I did change rad and thermostat as a precaution due to the dealer not taking the rad off whilst changing my timing belt.

 

[conaero]

or the water pump, was it changed last cam belt change and when was it and has it been noisy?

 

[Skid1769]

Cheers,
Just asking if there was any other possibilities before I go ahead and purchase one.

Appreciated

Stuart

 

[Skid1769]

belts changed at last service about a month ago, don't think the water pump was changed, however I think it is more likely the thermostat than the water pump as it seems to be an intermittent fault..??

 

[allandwf]

Possibly thermostat, but that doesn't explain no coolant felt in pipes, or do you mean no warm coolant?

 

[NickP]

Perhaps the fans on the rad are not working, normally when it gets hot they cut in, if they don't work then it will overheat I suspect.

 

[conaero]

Perhaps the fans on the rad are not working, normally when it gets hot they cut in, if they don't work then it will overheat I suspect.

yes, will only do it in traffic not whilst moving, especially in the winter.

Re the water pump, they should have checked it so thermostat is looking likely

Next time it does it an if one side of the thermostat is hot an the other cold, it is the stat.

 

[Skid1769]

Cheers gents, all appreciated, the inlet coolant pipe to the thermostat was too hot to touch whilst the outlet was manageable so looking more like the thermostat. Easy enough job to do plus cheaper than a water pump. Will change the stat first.

Thanks again for all your help.

 

[Contigo]

Water pump

 

[allandwf]

Water pump

Mr doom!

 

[Skid1769]

A bit more info, the fans are definitely working and I am not hearing any noise that might be indicative of a defective water pump.
The price of a thermostat and it being an easy fix, I will try that first, if it doesn't work then the next thing is as some of you say, the pump. Is there a check you can prior to taking it out??

 

[MAF260]

Have you bled the system? Could be an airlock.

 

[2b1ask1]

Have you bled the system? Could be an airlock.

True and a good call, a thermostat will often stay closed if it has air under it as it needs the water contact to conduct the heat and activate it. I had this on my old Landrover.

 

[Contigo]

There is a green resistor for the fans which fails and this can cause overheating but it sounds like yours is fine. Check Thermostat and then look for any leaks.

What is the level like at the header tank?

 

[alfatwo]

Head gasket failure maybe... Stuart at Shiltec said he used to do them all the time at Graypaul 15 years ago!

Dave

 

[SteveM]

I think I have been through all of these plus a few more
Sticking thermostat - mine was stuck open so really struggled to get heat through vents but wasnt overheating that time!
Failed resistor on bottom of radiator - if I recall when this fails the fans dont increase speed leading to some overheating - again relatively cheap part but probably rad out to undo screws fixing it to radiator
Leak on Radiator front core - look for tell tale signs of antifreeze under rad. Mine had a core rust out on smaller front radiator which I got recored as well as replacing the 3 silicon hose pipes linking to the larger core behind.
Final issue was loss of cooling liquid that was tracked down to the small 6" pipes linking block to turbos - perished on the end due to heat and corroded clip - again a very cheap fix with silicon pipe but need to remove alternator and or A/C compressor - again look for tell tale signs of antifreeze half way back under engine after car parked up overnight as any leaks evaporate when engine hot

 

[urquattrogus]

Try the old kettle test on the thermostat you take out?

 

[Gp79]

I've only ever had a thermostat stick open so the car would never reach normal operating temp.

Hopefully just an air lock, it is unlikely that a timing belt driven water pump would start and stop working.

the fans are only needed when there is no air flow - i.e car is stationary, so you can rule that out unless it overheats when stuck in traffic etc

 

[Skid1769]

Appreciate all your comments, some quite severe issues there, hopefully none of them.I will get the thermostat out and give it a check but one from Eurospares is £85 plus vat. It probably hasn't been changed in the life of the car so it will be 15 years old now. Has anyone used this waterless coolant I have seen advertised?.