Outer Limits 4x4 Board

hey guys i have a 96 gq patrol ute with a td 42 and have got a overheating problem, it gradually overheats doing 100/110kph on the highway with the aircon on, turn aircon off and it slowly returns to normal, the stock radiatior was rooted so i replaced it with a aftermarked heavy duty ally one have tried removing the engine fan and fitting ford thermo fans both made no real difference, tried new thermostat no difference tried pulling the guts out of a thermostat no diff! i live in the pilbra in WA where temps are usually high 30 low 40s but wouldnt think it is too hot for it. doesnt use any water and have replaced water and coolant, cooling system does hold pressure! ah dont know what to do next waterpump???
any ideas????
pleaassseeeeee

Hey Rugs , Best use the original clutch fan and make sure it is good if not new , Is the fan shroud good (no body lift ) so that the fan draws the air through the radiator ? Do you have any mesh/ flyscreen in front of rad ?
Is the A/C condenser blocked ?
On a hot day with A/C on mine will get to 2/3rds on the guage but then the fan cluctch locks up and holds its temp at 2/3rds I have a turbo with tricked up pump on mine too so it has higher EGTs to contend with.
Are you running a turbo ?
Is your air cleaner element ok ? - unburnt fuel causes high combustion temps also - make sure she can breath!!!
I have thought of fitting a high volume electric water pump - you can get a davies craig one that fits inline with the bottom radiator hose to get the flow rate up . Good luck Christo

christo400 wrote:Hey Rugs , Best use the original clutch fan and make sure it is good if not new , Is the fan shroud good (no body lift ) so that the fan draws the air through the radiator ? Do you have any mesh/ flyscreen in front of rad ?
Is the A/C condenser blocked ?
On a hot day with A/C on mine will get to 2/3rds on the guage but then the fan cluctch locks up and holds its temp at 2/3rds I have a turbo with tricked up pump on mine too so it has higher EGTs to contend with.
Are you running a turbo ?
Is your air cleaner element ok ? - unburnt fuel causes high combustion temps also - make sure she can breath!!!
I have thought of fitting a high volume electric water pump - you can get a davies craig one that fits inline with the bottom radiator hose to get the flow rate up . Good luck Christo

an electric water pump wont work on a td 42 as it uses a bypass system where the coolant is always recirculating in the block and head and the thermostat controls how much is recirculated and how much cooled water enters ,coolant flow isnt the problem either as it flows way more than enough

Hi christo400
yes it is turboed with more fuel, also has body lift 2inch, will put the old fan back on should I try a new hub? Do they play up? And aircon condenser ect is clean

yeh the hubs do play up from time to time. If its the hub tho generally it will just run damn hot irregularly until it completely fails (ie just idleing along might go off the guage if ur not watching temp). Yours sounds more like a cooling capacity problem... like has been said - air flow (make sure u have rubber bits where they used to be so that air has to be sucked through radiator including the gap between cab and chassis in front wheel arch)

might be a tuning problem - too much fuel

Should be able to hear fan kickin in or watch for it as temp rises... Feel if temp is circulating through radiator from cold with no termostate... Blocked air con condenser from christo sounds on the ball! My two cents anyway.... have fun
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Mate the clutch fan hubs are full of oil, which can basically wear out over time, you can buy the oil from any toyota parts place (not sure about nissan) it just requires opening the hub up (it should have screws/ bolts in it). i did this to my pop's overheating pajero with the toyota oil and it fixed it.
Other thing to check is water pump, not sure if td42 has plastic or steel impellers, but either can cause problems.
Theres no oil in water or vice versa? No white smoke?
There is also a product available for cleaning out the sludge diesel's get built up inside, id have to get its name, but its 100 odd dollars and has fixed countless overheating 4bies, according to magazine article on it.

id be pointing fingers at blocked condensor, or water pump. realistically unless u were towing 2ton at 110km/hr the au fans do the job plenty well. Plus the fact at 110km/hr the amount of air being forced through the radiator would take a lot of flaws out of the fan as it shouldnt need to work on the highway.

Blake

thanx robbo
when i had the mechanical fan you gould really hear it whizzing so i think it was pullin plenty of air, think i will pull off the water pump and check it out, will give the aircon another blast make sure it is all clean
cheers for ideas

checked air con condensor few bugs ect in it but definatly not blocked, will pull the water pump off tomorrow and see whats going on

fit a hotter thermostat , dont bother trying to make it run cooler as you wont get anywhere without spending heaps of wasted coin , a 90 deg thermostat should work fine , it basicly increases the difference between ambiant air and coolant temp which makes it easier to remove the heat , i have been there and done all things to stop over heating and this is the only thing that has worked and it is cheaper than throwing money at it and hopeing it will work