Cooling System Problem

[smith281]

Hi Guys,

Having some trouble with the cooling system on my 4.5L Petrol GU, hoping you can help!

The plastic housing at the top of radiator cracked and bust, and then the engine overheated.

I've bought a new radiator now (plus new cap) but I now want to eliminate any other problems that may have caused the old radiator to burst in the first place. I don't want to break the new radiator which was expensive!

Thermostat - removed it and checked it in a pan of water. It seems to work fine.

Cooling pump - I've not taken it out to check it yet. But when I've disconnected the return hose to the radiator and run the engine, the flow coming out of the hose is not very high or steady. I did this after completely removing the thermostat from the housing. Even while revving the engine, the flow through the return hose is not steady at all. Nothing comes out at all, and then every 15s or so a burst of water comes through. Is this normal? I would have expected a steady flow from the pump.

Head Gasket - I'm planning to take the car to a local garage for a block test. The test where they draw the gases from the cooling system overflow tank through a liquid and check for combustion gases in the system.

Do you have any other advice, experience or suggestions?

Thanks a lot,
Tom

[BJNSW]

Tom,
I have just been through a similar process.
My GU 4.5 liter petrol (194000kls) started to overheat going up hills and air con would shutdown.
The original radiator was partially blocked and wouldn't clear with backflushing.
I have fitted a new 3 row all aluminum radiator ( standard is 2 row) and fitted new thermostat.
I have also fitted new Water pump, fan belts and top & bottom hoses.
I purchased all items over Ebay and was amazed how cheap the parts bill was.
Geniune Radiator was over $920 new 3 row was $325 delivered from Melboure.
I have now done 3000kls since install and car runs much cooler and Air con no longer shuts down.
PM if you wont details of Ebay purchaese.
BJNSW

[smith281]

BJNSW, thanks for that. Foolishly I already spanked out on the Nissan Radiator! I'm based in Qatar so it would probably take ages to get an all aluminium radiator shipped over in any case. They do look great on ebay though and look a lot more robust than the plastic Nissan ones! Like you I think I will look at replacing the water pump, hoses, fan belts and thermostat.
Cheers.

[eddietrx]

These just go brittle and crack mine did exactly the same

[stets]

once you overheat an engine, it is always best to replace the thermostat, top and bottom radiator hoses, water pump, change the oil, radiator cap, test the engine for compression, and also check cooling system pressure.