overheating at speed

[mickyd555]

I drive a GU ute for those who dont know, TD42 N/A engine. standard nissan alloy bullbar with two narva taurus bull spotties mounted out on front. coming back from werock the other week i started to overheat. spotties were on. found the radiator to be clogged up with mud, washed it out and headed home.....no worries.

Today driving at highway speed, it started to overheat again. spotties were not on (day time) sitting on 85-90 km/h @ 2100 RPM, its sweet as. up a few revs to about 2300-2400, the temp starts to climb, back off and it comes back down again. fluid levels are good and i have not had any problems prior to the original time it overheated.

any advice or ideas on what to look at are appreciated.

[RaginRover]

How many Ks and how old, my guess is the radiator needs cleaning, as in pulling apart and cleaning by a radiator place.

I use Oxley radiator service and they will strip down, clean and pressure test a rad for you for $70 last time I had one done.

If you car is getting toward 10 years old there is a good chance it is full of crap and not cooling efficiently - that is the first sign of a failing rad on a rangie

Tom

[mickyd555]

2000 model with 171 000 ks

[dirtyGQ]

Yeh my car does exact thing really strange , has new radiator so mechanic suggested flushing the block (water galleries etc) have not done yet but will let you know how i go . 4wd shop said if at speed it is a water flow problem

[ozy1]

may be thermostat blocking/stuck closed, or stuck fully open or something strange

[blackmav]

Check your clutch fan.
Replaced mine a year ago with exactly the same symptoms and yesterday I got it up to just under the hot mark (about 3mm away), stopped and turned it off and I could free spin the fan, not good. Only gets hot at highway speeds with a bit of load.
You can pull Diesel ones apart and replace the fluid with new liquid, petrol ones are not rebuildable.

[ozy1]

on that note, if you want to, you can buy a replacement diesel hub, and a fan to suit through repco, then you have the rebuildable option at a later date,

just remember the actual fans are different between petrol and diesel, the difference is in blade shape and distance between mounting holes for the hub,

on that, i have a diesel fan and hub on my petrol patrol, and it works fine,

[HotFourOk]

I didnt think a fan being on or off would affect the cooling when sittting around 100km/h
The wind rushing through the radiator would be sufficient and a fan would not be needed at that speeds one would think.

Is your water pump functioning optimally?? When you increase revs, if your pump fins are worn, it may not be throwing enough water through the system... just my 2c

[blackmav]

I didnt think a fan being on or off would affect the cooling when sittting around 100km/h
The wind rushing through the radiator would be sufficient and a fan would not be needed at that speeds one would think.
Is your water pump functioning optimally?? When you increase revs, if your pump fins are worn, it may not be throwing enough water through the system... just my 2c

Apparantly not, I didn't think so either but its pretty common.

I can cane the living bejesus out of mine in the bush and round town as well as towing a horse float but soon as it goes out on the freeway on a warmish day and sit on 110/120 it heats up.