Thread: At a loss: Chronic overheating

If you are replacing hoses, while the coolant is out, the often ignored heater hoses that attach to the firewall are good to do, they don't cost much and you can keep your old ones for spares. Heater hoses have often been the culprit of coolant loss.

Your on the right track with some good solid advice.I had a head gasket go early this year on a 3.9 and there are no signs with these engines except for 1 which was excessive water splattering out of the exhaust so then I had a TK test done and proved it was the head gasket..I stripped it down ready to do the heads but then noticed 1 of the cylinder liners had dropped a tiny bit so the engine was then a throw away.The cause of overheating for me was air locks after replacing a water pump that had the fan bolt snap off and also the radiator needed rodding which makes a huge difference and will get it done every few years to keep it working properly.Good luck.

Originally Posted by shamat

Pulled the radiator and took it to be cleaned and rodded. The guy had one look at it and said "thats completely ****ed!"

Wasnt obvious at first, but many of the inner core fins had collapsed. From the outside it didn't seem so bad, but dig deeper and it was a nightmare.

Nowing having a new core put into it and will report back once its all together. Also got a new viscous fan clutch and top and bottom hoses being put in at the same time.

the fins on the radiators rot out fairly quickly these days, the sulfur from unleaded exhausts reacts with the copper fins and they flake away.
mine did the same thing and was overheating when under load.

I pull the radiator every now and then and flush it blow it out and then wash the core fins but not with a pressure washer as they tend to bed the fins.

If any of you do this, make sure you blow as much dust and crap out first as if it dries in the core then it turns to immovable mud and your up for a core.

If you pressure test the radiator with the plugs out it should tell you fairly quickly if the head gaskets gone.

I think your on the right track, all the stuff you have done should be done if you do the head gaskets anyway so it's not going to be a waste.

Cheers Casper

Thanks everyone for the suggestions and help. As all the parts came in during the week I got started on fixing everything today and I'm pleased to say I've nailed it!

I had the radiator recored and put that in with new hoses top and bottom. The fan clutch was impossible to take off as per the manual, so I removed the water pump with it still attached. 2 mins in the vice and I had it off. This gave me a chance to inspect the pump which was quite good. Also checked the idler pulley and it was good too..

Couldn't get a gasket for the pump so I did it the old fashioned way with paper and a ball hammer. Got the pump back on, rad and hoses installed (what a pita) filled with coolant and put the new fan clutch on..

The sound from the fan is noticably different with a lot more air flow and no more over heating issues. Looking forward to getting it off road now.

if you've gotten the fan off by gripping the impeller in the vice and then unbolted the fan stand by to replace the pump....

Originally Posted by Blknight.aus

if you've gotten the fan off by gripping the impeller in the vice and then unbolted the fan stand by to replace the pump....

Pump is working properly. No slipping of the impeller on the shaft. Tested that before putting it back on.

Im betting that you tested it while it was dry and cool.

Might not be a problem if you have a cast impeller in the pump, if you have one of the folded/pressed metal ones however...