Hi,

I have a 91 GQ Nissan Safari. I am having issues with it not getting upto temp and then when pushed will overheat.

About the truck:
Aftermarket Kinugawa TD05 water cooled
top mount inter cooler
custom air manifold, air box, 4" snorkel
4" straight thru exhaust

Things I have tried:
New radiator
New nissan rad cap 1.1 bar
new nissan water pump
new nissan thermostat. Tried a tridon 82 deg, tried a 88 deg nissan one for a terrano, tried a aftermarket modified one with a longer bottom section to block the re-circulation better (from Trundles automotive in NZ)
re oil fan hub
new fan blade
has shrouds around radiator

I only had the truck for 1 month before I removed the entire front plate due to a small water leak by the injector pump at the same time I removed the head and did the turbo ect. so I don't know if the issue was already there or not.
I didn't actually remove the injector pump from the front plate as I didn't want to play with the timing.
All new nissan seals, head bolts ect.

I think the overcooling can only be caused by a faulty thermostat? what other things could cause this?

I have also put reco higher crack pressure injectors which I did read somewhere could affect the temps?

Just went on a camping trip with the trailer about 4500kg GCM and it did sit at about 82 deg consistently but would sometimes drop right down to 40 deg when on level road and any hill would see the temps rise, never went above 100 deg but the hills weren't that big. Pyro was sitting on 350 ish and upto 500 max on hills (100mm after turbo in dump pipe)
unloaded it struggles to get above 60 deg unless going up long hills where it will go up to 100 so I stop and turn around it drops to 40deg rapidly.
Just went for a run without the thermostat in and wouldn't go above 60deg up a long hill and when heading back down temps dropped slowly at a steady pace.

This makes me think the rad and most other bits are working but the coolant must be bypassing the thermostat somehow?

Is there only one type of water pump that will fit this motor?

I have also noticed that the rad hoses don’t seem very firm when the truck is running. Should the only be hard when at operating temp?
No water in oil or bubbles in overflow and water level doesn’t drop over time.

Sorry for the long post but better to get all the info on the from the start.

Cheers
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