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Nissan Diesel running hot up hills
Posted: Mon Nov 08, 2004 10:19 pm
by Trav
Does anyone one no of cooling fixes for these things, my work car a toyota 4.2 diesel pulss a tandem with a tractor on it all day long and the temp dosent budge, i drive my nissan moderatly hard and the temp goes up i have put a new radiator in it and there is nothing wrong with the engine everyone i no has the same problem, would a 17 inch thermo by itself keep it cool with no engine fan??
Posted: Mon Nov 08, 2004 11:20 pm
by patrolman
more info would help eg 3ltr, 4.2 etc
Posted: Tue Nov 09, 2004 7:33 am
by 80diesel4play
A diesel only runs hot when they are under load - up a hill at noise is a good example. Unlike a petrol engine where teh fuel is used as a coolant of sorts - a diesle doesn't work that way.
If you're towing and it fine - its probably cause you aren't giving it a heap of rev's. Ging up a hill does wierd things to ones right foot!
Try a set of XR6 twin thermo's they aren't expensive at all - $250 for a set new from some places... They come with a good shroud and will keep the car cool and then some... Single one on its own wont cut it on a diesel - too much surface area not having air drawn through it!
also check the water pump to make sure thats okay as well.

Posted: Tue Nov 09, 2004 7:48 am
by bogged
Singo has pretty much said it..
Its not uncommon for TD42s to run hot when given a hard time...
Check a few things.
Thermostat
Radiator cap
Clutchfan
Waterpump
Radiator Hoses
Have the cooling system completely reverse flushed - you will be amazed how much shit is in the system - then add good quality coolant.
Also check the archives on
http://forum.patrol4wd.org/phpBB2/
Too Hot
Posted: Tue Nov 09, 2004 8:08 am
by Not For Highway Use
I had the same problem. Check the viscus coupling on the fan. Thermo's work but don't like mud and you need a bypass switch for water. Also make sure the the whole system has been flushed. I replaced everything, waterpump, thermstat housing and thermostat. Fixed the problem for me.
Posted: Tue Nov 09, 2004 7:47 pm
by J Top
Check your fan when the engine is hot.If you turn the motor off when the engine is hot and the fan keeps spinning the viscous coupling is faulty.
I have "repacked " several of these with new fluid,just split it add the fluid and reassemble,don't remove any of the existing fluid.
The only time it hasn't worked has been on a TB42,the coupling dosen't come apart.
J Top
Posted: Tue Nov 09, 2004 8:53 pm
by Camshaft1
Have you got a body lift. after i fitted blocks i find it runs a bit hotter. i'll move the radiator one of these days.
Posted: Thu Nov 11, 2004 11:03 am
by Big Red Toy
yeah bodylift can screw things up 4 ya, mine's got 3" bodylift and it gets pretty warm on real long hill climbs, but then again thats foot flat to the floor the whole time
Try flushing the system, if its a major problem, during summer remove the thermostat from the housing to prevent further restriiction
Posted: Thu Nov 11, 2004 11:37 am
by hottiemonster
Big Red Toy wrote:yeah bodylift can screw things up 4 ya, mine's got 3" bodylift and it gets pretty warm on real long hill climbs, but then again thats foot flat to the floor the whole time
Try flushing the system, if its a major problem, during summer remove the thermostat from the housing to prevent further restriiction
yeah but yours is a petrol

Posted: Thu Nov 11, 2004 12:06 pm
by Guy
Big Red Toy wrote:yeah bodylift can screw things up 4 ya, mine's got 3" bodylift and it gets pretty warm on real long hill climbs, but then again thats foot flat to the floor the whole time
Try flushing the system, if its a major problem, during summer remove the thermostat from the housing to prevent further restriiction
I say that removing a thermostat is poor advice, as they fliud may not spend enough time in the radiator to cool effectively.. you should always make sure you have a good quality thermostat installed to allow the engine to run at the temp's it was designed to run at ..
Posted: Thu Nov 11, 2004 5:13 pm
by J Top
Thats not counting the fact that it is a twin acting thermo, and removal can allow the water to bypass in the housing without going through the engine block.
J Top
Posted: Thu Nov 11, 2004 9:14 pm
by Trav
yeah ill check the fan dosent sound like its comin in, i have a body lift and a turbo running 18 psi i have lowered the radiator to where it was factory had new radiator put in, i guess ill pull the fan off and put some more oil in, see how that goes, thanks for the info.
Posted: Fri Nov 12, 2004 3:29 pm
by John H
My 4.2 has a turbo (no intercooler) and runs 12psi boost. It used to run pretty hot. I tinkered with the fan cluch and it didnt help much. Got a three core radiator made up and it now runs at no more than 1/3 on the temp gauge. At first I was conserned that it ran too cold so I removed a whole bunch of fluid from the fan cluch. The new radiator cost around $600 and I now feel a lot happier on desert trips and long steep hills.