KV6 overheating

[chillyphil]

Mg zt-t 190.

Hi all,

Out and about last night when the engine overheat flashed on the IPK for a few seconds and went out.
The engine temp indicator maxed, then slowly returned to normal.
Luckily I was at the top of the hill, so in neutral with the engine idling, I managed to get home without any serious overheat.

This morning, put around 3 litres in the system, bled it on the engine hose, and started up.

Looking at the torque ap, temp rose to normal, then slowly crept up to 96.

After a few minutes I revved the engine to 3000rpm for a moment or two, the temp went up to 102.
I shut it down.
During this routine the high speed fan on the rad came on and off sporadically.

When the engine was off and cooled to around 70, I turned on demist, the interior fan came on, but the rad fan didnt, same happened when I tried the air con on lo.

I didnt seem to lose any fluid during this time, even when the temp went over 100 so I am assuming the thermostat housing is ok?

Any thoughts on the cause before I start messing around and making it worse?

Phil

[grs6680]

is your fan working properly.i think you may need a new resistor or new bushes sorry didnt check age of your car.

[stocktake]

Your radiator fan should come on low speed at around 100 and stay on until 95. If it doesn't then you have a problem with the fan, that could be a failed resistor, relay or fan brushes.
Regardless of this your car shouldn't overheat just because of a failed slow speed fan, the next speed should come on at around 106 and cool the engine.
It could be a combination of a failed low speed fan and a sticking thermostat.

1st job is to find out if you have a 2 or 3 speed fan.

[chillyphil]

Thanks Dave and Gordon,

How do I check what fan set up I have?

It's an 03 reg.

[stocktake]

Originally Posted by chillyphil

Thanks Dave and Gordon,

How do I check what fan set up I have?

It's an 03 reg.

Look through the grill at the front, behind the fan at approx the 2 o clock position you will see a silver resistor around 15mm x 15mm x 70mm (ish)
if not it is (almost) certain you have the older type 3 speed fan.

[SD1too]

Hi Phil,

Originally Posted by chillyphil

... put around 3 litres in the system, bled it on the engine hose ...

3 litres is a lot of coolant to lose. Remove the engine acoustic cover and check the 'V' for leaks from the thermostat housing 'O' ring.
When you bled the cooling system, did you raise the expansion tank with the engine not running?

.. the temp went up to 102 ... the high speed fan on the rad came on and off sporadically.

That sounds like a 2 speed system with a failed resistor, but I await your confirmation that you have a resistor.

I didnt seem to lose any fluid during this time, even when the temp went over 100 so I am assuming the thermostat housing is ok?

Don't assume Phil, look into the 'V' and find out for sure.

Simon

[Paul Taurai Chitsaka]

Hie ther hope u all wel, i had a semilar problem with overheating,when we checked it was burning oil and pressurising,so got a mechanic to open head only to find out rings were gone..rover75 l.8 litre.

[Dallas]

Take the expansion bottle cap off and run the car from cold, see if you have water returning from the little return valve hole in the neck of the bottle, chances are is that you don't.

I bet coolant quickly rises and spills out within seconds, you most probably have a blocked corroded oil cooler

[chillyphil]

There is no sign of oil and water mixing either in the cooling or oil system.

The coolant return just inside the reservoir is working ok.

[Dallas]

Originally Posted by chillyphil

The coolant return just inside the reservoir is working ok.

Have you tried starting the car from cold with the cap off, does the coolant level instantly rise and spill out?