Overheating when towing

[Robyn Brown]

Our 1998 GU petrol/gas TI has begun to overheat when towing. We have had the thermostat replaced twice (to make sure that wa asnt faulty, 28 yr old radiator cap replaced, radiator fan and clutch replaced and all hoses replaced. se have been told the next thing is to service radiator @$600 or fix a cracked head $3000. We have had Penrose test for cracked head but the result sas negative although they did say some GUs dont show up in this test. Currently it overheats from standing to acceleration eg after stopping at an intersection but comes down again after awhile. Has anyone got any ideas?

[mudnut]

Hello, and welcome to the forum. Please head over to the introduction section and tell us a bit about yourself and your Patrol.

Is the fan clutch ok? Check it by giving the fan a spin. It should stop at most 1/2 a turn. Have you got all of the original fairing on the radiator?

You may have a build up of mud and leaves in the bottom portion of the radiator fins.

[GQtdauto]

Hello Robyn , is yours an auto or manual ? What is the weight of the thing your towing and is it a recent purchase .

[Avo]

i have no idea,so i'll just say welcome to the forum....and there's a heap of knowledge here...

[VK2FMIA]

As Mudnut said, check the fins in the radiator. My GU was overheating a bit & after removing the shroud & pressure cleaning the radiator, problem solved. Surprised at the amount of dirt & grass seeds that came out.

[the evil twin]

Why did you have a 28 year old rad cap on a 19 yo car? Typo?

Anyhoow... I'd say it is almost 100% chance the bottom fins on the rad are choked with bugs, mud and general crud and the Rad core blocked.
I would pull the Rad out and get a newbie/exchange/recore or at least get the old core rodded out depending on your budget and what you find with it out

[BillsGU]

I agree with ET - but I would not spend any money on a 20 year old radiator. Mine is an aftermarket alloy which is thicker and more efficient than the OEM, and it was around the $400 mark.

[GQtdauto]

Replaced the radiator in the GU because of overheating and it did Diddy squat , had system flushed and still the same , worse when towing up steep hills or on hot days while towing .
Going up to the lookout at Townsville not towing it boiled by the time I got to the top , new water pump , new radiator and full service , fan checked and ok so thinking old motor with a fair few Kay's on the clock might be the problem .