MG ZT 1.8T coolant loss

[Lotus7]

Help please. I have a 2003 MG ZT 1.8T which has decided to lose coolant once engine is turned off. Cooling system appears to be over pressurizing and the cooling fan appears to not come in anymore.
Car has had 3 HGF tests all of which were negative. 2 garrages have had 6 looks at the problem with both saying they cannot get the car to replicate leak and or get the engine hot enough to have cooling fan cut in!!
The casr was perfect until it had service 6 months ago when the MGR garage flushed out cooling system as part of service. It has leaked ever since.
I am going nuts...............Please help if possible.

Lotus7

[T-Cut]

One favourite leaky spot is the plastic T-piece just behind the radiator at the top. Check the pipe dropping down to the PRT. You'll see pink staining if the joints are leaking. If so, replace the silly clips with Jubilees and retighten carefully. If that don't work think about commisssioning a GerryTee.

As to the fan, what year is the car?

[Kandyman]

Welcome to the forums David,

Sorry to hear about your problems.

Where about in the country are you located as few have some good garages and members around the place that could offer some help.

[Lotus7]

Thanks, coolant appears to leak from 3 areas depending on length of drive. Short drive = t - piece/ little pipe running down from it. Medium drive (10 miles +) = from T piece and the top hose as it goes into the top of the radiator. Long drive (Motorway) = from t-piece, top of radiator and I think from the expansion tank as a couple of times I have seen coolant on the air box cover.
The amount of coolant loss is minimal, maybe 1/2 litre (max) a week (car is used daily).

The car is an 03 plate.

Also, where is the temperature sensor for the fan/temp gauge so I can check/clean terminals to see if this makes fan cut in.

Originally Posted by T-Cut

One favourite leaky spot is the plastic T-piece just behind the radiator at the top. Check the pipe dropping down to the PRT. You'll see pink staining if the joints are leaking. If so, replace the silly clips with Jubilees and retighten carefully. If that don't work think about commisssioning a GerryTee.

As to the fan, what year is the car?

[Lotus7]

Chelmsford in Essex

Originally Posted by Kandyman

Welcome to the forums David,

Sorry to hear about your problems.

Where about in the country are you located as few have some good garages and members around the place that could offer some help.

[sworks]

The temp sensor is on an alluminun housing on the right hand front corner of the cylinder head as you look under the bonnet. If the connector is disconnected with the ignition on the fan should run - keep you hands well away from the fan :lol:

[T-Cut]

Originally Posted by Lotus7

Thanks, coolant appears to leak from 3 areas depending on length of drive. Short drive = t - piece/ little pipe running down from it. Medium drive (10 miles +) = from T piece and the top hose as it goes into the top of the radiator. Long drive (Motorway) = from t-piece, top of radiator

Clearly all the connections to the plastic T-piece are leaking. Try a new Jubilee clip on each and tighten judiciously to avoid distorting the thing. If that's not completely successful, I'd go for the custom built steel one. Details under 'gerry' postings.

I think from the expansion tank as a couple of times I have seen coolant on the air box cover.

The cap may be releasing coolant due to an over-heat developing when the fan isn't effective. The cap may be weak and need replacing.

The amount of coolant loss is minimal, maybe 1/2 litre (max) a week (car is used daily).

That's too much to ignore. You cannot afford leaks on that scale without risking head gasket failure. You should fix them asap.

The car is an 03 plate.

Difficult to say which fan type (2- or 3-speed) you have. Switchover happened around late 03. I'd suspect a worn slow speed brush, but if it's the later type, the slow speed resistor has failed. Does the fan operate when the air conditioning is switch on (Auto)?

where is the temperature sensor for the fan/temp gauge so I can check/clean terminals to see if this makes fan cut in.

Here's a picture of mine.




Hello boys!

[Lotus7]

Thanks for the pic and the info. I have a 2 speed fan which works fine when Aircon/climate is turned on.
As for too much of a leak - yep you are right, however 1 drop is too much. In saying that, car has now done 7000 miles with the leak, so you can pretty much guess how frustrated I am with the problem.
And yes, the expansion cap is brand new. Cured problem for all of 3 days!!
Just a silly question. Is there a way of making the fan cut in permanently to see if it is actually working?

Thanks for all of your help.
David

Any clues

[Dave Goody]

Originally Posted by Lotus7

Chelmsford in Essex

Now who lives around here PM sent Dave

[T-Cut]

Originally Posted by Lotus7

Is there a way of making the fan cut in permanently to see if it is actually working?

Since the fan runs continuously when the A/C system is on with engine running, the fan motor is obviously OK and the slow speed resistor is functioning. It would only operate every 30 seconds, on-off-on-off, at high speed if the resistor was dud.

If you detach the sensor wiring, the fan should trip into emergency high speed cooling mode. It sounds like the sensor or its wiring is faulty. Have you run the coolant temperature diagnostics to see what it says? See: http://www.the75andztclub.co.uk/foru...ng+temperature