[Yake]

Hey guys, I have a 91 sj70 and it seems to get hot fairly quick (Doesn't overheat but gets to the top 3/4 of the gauge fairly fast) when I take it through more technical tracks/up hills I'm guessing its cause I'm moving slow and there's not enough air cooling the engine. Pretty much just wondering if this was normal and what I could do (relatively easily ) to stop it getting hot so fast. Thanks

[rmd1]

Additional thermo fan wired to a switch

[bumstein]

Heaps you can do that MIGHT help

Flush out radiator and cooling system and make sure nothing is gunged up in there
See if anything is blocking airflow through radiator such as heaps of bent fins
Replace radiator if it's cactus
Replace thermostat (or at least take it out and see if it's working properly)
Replace water pump if that's old

And yep a thermogram might also help

Edit: I'd also be tempted to make sure it is actually getting hotter than it's supposed to. If you have or can borrow a temp guage to temporarily put in there and see what it tells you

[atari4x4]

just replace the viscous fan clutch

[MrRocky]

No viscous fan on a sierra
Unlikely to be waterpump which leaves radiator or thermostat.
Thermofan pointless unless uber slow rockcrawling
My guess is theres no thermostat in it or your rads stuffed.

[MrRocky]

A new genuine thermostat and new alloy ebay rad will cost you less than $150

[alien]

Smell your overflow bottle. Seriously... see if it smells like petrol / exhaust.

I've had 2 head gaskets leak (g16 though) which caused overheating because the coolant linked up with an intake port on the head between cyl 2 & 3...

Took AGES to figure out that's what it was - and the only symptom was the overflow bottle overflowing, and the coolant smelling like fuel fumes.

(that's worst case scenario)

[Yake]

Thanks all for the feedback, I'll suss out all the simple things suggested first (radiator condition etc.) before I think about auxiliary fans and stuff haha.

alien wrote:

Smell your overflow bottle. Seriously... see if it smells like petrol / exhaust.

Well it doesn't smell like petrol or exhaust.. But it is an old powerade bottle so... haha

[shep]

I would confirm that it is getting hot before stuffing around with anything. Might just be the temp sender or gauge playing up a little.

[alien]

^^ and that - i bought a cheap IR gun to poke around the engine bay when figuring mine out. I learnt that between 1/4 on the temp gauge and 1/2 way, there's a 5 degree difference. So it looked like an alarming rise in temp but wasn't really.

[MrRocky]

A sierra should never go over 1/4 if radiator, waterpump and thermostat are functioning correctly. The standard cooling system really is more than sufficient even for a 1.6 motor

[Angus Martin]

Has it got spot lights or a radiator fan shroud?