2.8 Hi-Lux overheating

Submitted: Monday, Mar 19, 2007 at 23:26
ThreadID: 43431 Views:1854 Replies:7 FollowUps:0
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My 2.8 Hi-Lux overheats at hiway speed (100k) with the air -con on. Radiator is new, thermostat is new,(it overheated yesterday with the thermostat out). The radiator cap is new, there is so much pressure it splits the solder on the top tank. Could it be the fan clutch, I thought at 100kph the wind speed would push enough air through the radiator to cool it. The injector pump was done up before this trouble started, it doesn't have the same power as before. Petrol engines overheat on a lean mixture, are diesels the same. Has anyone had the same problem.
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Reply By: long haired nomad - Tuesday, Mar 20, 2007 at 00:16

Tuesday, Mar 20, 2007 at 00:16
With the engine cool or warm, take of the radiator cap off , start the engine and see if the water is circulating. Might be the water pump. Check the overflow tubes for blockages and check the overflow bottle. Only have it( the bottle) half way between the full and add mark. Where did you buy the radiator from? Is it a genuine one made in indonesia?lol. I had problems with mine after replacing it. I thought i had a cracked head or blown head gasket, but it was that i had the overflow bottle at the full mark. That caused the level in the bottle to drop and or increase making me think i had major problems.
AnswerID: 228474

Reply By: Member - Bucky (VIC) - Tuesday, Mar 20, 2007 at 05:15

Tuesday, Mar 20, 2007 at 05:15
Sounds like its a head gasket, or your block is full of gunk

Have you done an engine flush ? If you decide to add that engine flush stuff,, make sure that run the return hose, from the motor, thru a stocking ( or similar type fine mesh ) to catch all the gunk, otherwise it goes back into the radiator, blocking it up

Is it a head gasket ? To test start up with the radiator cap loose, run the motor up hot, and look inside the radiator, it will bubble if there is a blown head gasket.

Have you thought about a new water pump ?

Cheers Mate
Bucky
AnswerID: 228479

Reply By: traveller2 - Tuesday, Mar 20, 2007 at 08:27

Tuesday, Mar 20, 2007 at 08:27
The best way to check for a blown head gasket is to remove the cap to remove any residual overnight pressure, refit the rad cap, start the engine cold, run for 30 secs and turn it off, open the cap and if it is under pressure already you have a compression leak into the cooling system.
There is also stuff that can be put in the coolant to indicate combustion residue.
Depending on objects in front of the grille (bullbar, lights etc) and wind direction there may be bugger all airflow though the radiator at speed. 70 series cruisers are renowned for this!
AnswerID: 228492

Reply By: Member - Stephen M (NSW) - Tuesday, Mar 20, 2007 at 13:04

Tuesday, Mar 20, 2007 at 13:04
The clutch fan do sh#t themselves in the luxs. I replaced myn at about 280k. If you replace it go genuine. Yes they are dearer but will work properly. Put the thermostat back in. With this out the water is flowing to quickly to cool down in the radiator. No even freeway speeds are some times not enough for air flow and the clutch fan will cut itself in to suck the extra air through. Sounds a bit suss that you had the pump done now it doesnt have the same power and is overheating which means running lean which will eventually do major damage to the engine. Do as said above as well and check for blown head gasket. Is it turbo'd ?? This could have an effect on it as well. For it to split the top tank I'm thinking head gasket. That is an extremely lot of pressure for it to crack the top tank weld. Regards Steve M
AnswerID: 228555

Reply By: Dave Thomson - Tuesday, Mar 20, 2007 at 14:23

Tuesday, Mar 20, 2007 at 14:23
Had a similar thing on mine, it turned out to be the bottom tank has only mm's clearance, took it to NULOOK radiators and they extended the tank for $100 and problem was fixed,
hope this helps,
Dave
AnswerID: 228574

Reply By: fishaholic - Tuesday, Mar 20, 2007 at 23:05

Tuesday, Mar 20, 2007 at 23:05
BDT,
im having heaps of dramas with my 100 series getting hot, your lux sounds like a head gasket, but also make sure the thermostat is toyota one. All toyotas dont like non genuine ones, the fan will make a difference at highway speeds, which alot of people do not agree with. You also asked about the lean mixture, from what i have learnt over the past couple of weeks this can also happen in diesels, im going through that with mine as we speak.
But I think yours is the blown head gasket, this will build up pressure in the cooling system in some cases.
AnswerID: 228707

Reply By: BDT - Wednesday, Mar 28, 2007 at 10:21

Wednesday, Mar 28, 2007 at 10:21
Thanks for all the info folks, I put 2 tubes of Toyota fan clutch oil in the fan clutch, problem solved, i did think that enough air would go through the radiator at 100 kph but that is not the case, evidently the aircon condensor helps stop the air flow.
AnswerID: 230196

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