Outer Limits 4x4 Board

I'm having a overheating problem with my 2.8 turbo hilux.

It runs fine around town but get it above 80km/h and any slight hill and the temp goes up. 110km/h on the freeway and it will sit just above half on the gauge but once again any slight hill and it starts to heat up.

If I turn the heater on this helps it but still gets hot, just at a slower rate. As soon as I hit a downhill it cools down straight away or even if I put it in neutral and hold it at 3000rpm it cools down really quick. I can sit on a hill in 2nd gear and it won't heat up or even hold it at high rev's on the spot or a long period. It just seems to be anything above 80km/h.

I have already done:
-Radiator out and checked
-new viscous coupling
-new thermostat
-a leak down test through the glow plugs
-removed rubber seal at back of engine bay and space bonnet up 5mm
-removed driving lights

I don't think it could be a water pump as wouldn't that make it heat up at any speed under load?

It's done 270,000km now and is pushing 80series diff's with 4.8's and 33's (only for the last few months) but this didn't affect anything originally and sits on the same rev's as it used to with the standard diff's and 32's.


I have put a boost gauge on it recently and its hitting just over 14psi under full throttle/load conditions which I was very suprised at and is way to high I think (the turbo was on it when I bought it and I haven't touched it for the 4 years I've owned it so I presume it's been running that boost for a long time).

Is the boost level causing this? Is the engine just getting old? Are the larger diff's taking it's toll? Time for a V8?

Any ideas/help would be greatly appreciated.

How long has it been doing it???

Under load??? Do you mean fully loaded, up really steep hills?? or cuising on the highway??

How much smoke is it blowing??? If it's overfueling then this will account for the heat. You should be seeing a lot of black smoke if this is the case!

What revs are you doing & in what gear??? They don't like pulling up hills under 3000 RPM & under 80klm/hr as there isn't enough air & water flowing to cool the engine!

I tow my race cars with mine, fully loaded with the family, tools, fuel etc. (Approx 4 tonnes) & going up cunninghams gap when the outside temp is high I drop back to 2nd & sit on 4000 RPM, the temp stays constant & it will never overheat!

I've had a turbo 2.8 Hilux for 12 years running the standard cooling system, give me a call if you wish, & I'll try & help you out!

Russ 0412 375742

Mine overheats pushing it pretty hard up cunninghams gap but mine is fueled pretty high with 17 PSI boost. This could be your problem if someone as played with the mixture screw. Also overheats on the beach pushing through soft sand. Aircon off, heater on and windows down.

might be time for your radiator to have a good rodding.

sounds like Im having almost the exact same problems with mine.. ive replaced both the radiator and the thermostat with brand new units.. ive been boosting 10psi for 18 months with no worries but thought that things might just be wearing out (270,000kms) so i dropped it back to 6 but with no luck! still over heating.. viscous fan on mine is only 12 months old so im doubting that is the problem!... im leaning towards 2 things! A new waterpump (W4036) 65 bucks and an hour or so to fit.. cant hurt!..
How long since you have had your injectors/pump looked at?? dont wanna go chasing a cooling problem that isnt there!
i feel like ive lost a bit of power high in the rev range so im thinking some new injectors and a tune up could fix everything!
let us know how you go!

Was thinking about the fuel. It does have one leaky injector but it doesn't blow any smoke so I don't think it's over fuelling.

I think I'm going to give the water pump a go. No harm in trying

before you go pulling the water pump out. Take your thermostat out. While your motor is COLD take off your radiator cap and see if there is a good flow of coolant running through your radiator when you run the motor. The flow should increase as you increase the revs. If this is flowing well your pump is fine. I've worked on a couple of maxi taxi hiace's that have 3L motors they done up to 400K before needing a pump, most of the L pumps are quite good they will leak like hell but not stop working when they decide to play up.

I change my water pump every timing belt change as it saves the hassle later

LuxyBoy wrote:I change my water pump every timing belt change as it saves the hassle later

Did the timing belt on my mums carolla a few months ago and did the same thing, I did the hoses and belts aswell since they were all out.

Checked my water flow and there is no problem with that. Now I'm really stuck for ideas.

Well it had a chance to sit in the garage for 2 months whilst I was away and second day home I changed the waterpump and it still overheats.
It's not blowing any smoke so I still don't think the fuels a problem. I think it's just starting to feel its age.

I reckon its over fuelling,mine was doing the same thing,exhaust temp would shoot up around 680 degrese on a hill in top gear,also in the soft sand,but it never blew any visable smoke.

yeah i'd have to agree with it overfuelling. Can you see a smokey reflection in your mirror at night? You normally can't see it during the day but at night with a car behind you i've been told the heat gets reflected in the mirror. Don't ask why it just does...