Landruiser HJ60 Diesel overheating in hot summers of 45C

I would next look at the thermostat and test it in hot water to see if it is opening all the way.

You say "rusty water colour". Then I would say that the whole cooling system needs a good and through clean.

With those temperatures where abouts are you located?

I agree it will be cheaper to have the system checked by a qualified person than blow up the engine

G'day, it will be the viscous fan clutch, only fit a GENUINE Toyota fan clutch as the generic versions are only as good as a hallf worn Toyota one. You could buy 2 tubes of oil from Toyota to refill your old clutch if it is Toyota clutch, but you are only postponing it to break down when your'e not ready, hoo roo

At those speeds with the a/c on and ambient temp = or > 45C I'd imagine anyone would be having problems - after all it is an old vehicle!
Particularly when climbing hills it is wise to change down a gear (higher revs equals greater fan speed) and climb at a slower road speed. As you indicated turning the a/c off can improve the situation, also putting the heater on hot with the interior fan on high is good for the car (but not the occupants)

Taking the radiator cap off with a very hot engine is a mistake, as is trying to put water into a hot engine.
As you have done, the best remedy for an overheated engine is to pour water over the radiator as the engine idles, and continue until back to normal range on the guage. But even then I wouldn't remove the radiator cap.

As another poster suggested the viscous coupling on toyota fans can become an issue (and need re-packing, not re-placing) but you indicate that it has been replaced with a genuine one (some aftermarket fan hubs never work properly even when new)

I chased a similar overheating problem in a GQ for years. It gradually got worse and worse till in the end I couldn't drive anywhere near highway speeds at any time.

I spent a fortune on radiators and the cooling system. I reconditioned the head all to no avail.

Get your fuel system checked out. The most common reason for diesels to overheat is overfuelling, second is running lean. A visit to a good diesel fuel system specialist saved me a lot of grief.

Duncs

Its best to go to a radiator shop. If it's pushing water out the overflow, then the first thing I'd do is have it pressure tested for leaks - it might have a leaking head gasket. As well as the pressure test, I'd get them to remove the radiator, unsolder the top tank and have the radiator rodded. While its our, clean out teh air cond condensor in front of the radiator. If all is OK, then remove the thermostat and test it.

And, have you got a turbo bolted onto it - that's a sure fire way to make a 2H overheat.

110 kph is way too fast for an old 2H powered Cruiser, at those temps you would be best to limit speed to around 95 kph maximum and turn the A/c off, they were never noted for their "performance" and hot conditions make it even worse as you have found out.
Make sure the coolant is at the right mix for your environment, rusty water definately isn't ideal.

Hi Naveed Merchant.

From what you describe, it sounds like your radiator is not exchanging enough heat.
Most common cause is internal and external blockage of the radiator core.

Without seing the vehicle, I would reccomend the following.

Remove radiator and have it rodded and cleaned up properly.
Flush the block and heater core, replace any perished or aging hoses etc.

Things to check whilst doing so are.

check operation of thermostat, but I would not expect it to be the cause of the problem or you would have mentioned other types of problems.
Ensure good air seal of the fan/ rad shroud to the radiator.
Get some self adhesive 5mm foam used to seal up doorways, and use that to ensure no air gaps where the shroud fits up to the rad core.

Check the fan clutch for correct operation, and the fan for missing blades and the water pump for any play in its pulley/ impellor shaft.


Also, if its got hot, wont hurt to do a CO test to the cooling system, only takes 5 min to see if any combustion gasses have entered the cooling system indicating a possible failure of the head gasket.
Not trying to scare you, but its always prudent to check these things as a matter of course when a motor has overheated, or gotten hot.


My money is on a blockage, either internal or external in the rad core from what you describe.

Works ok when cool and not pushing it, but when more is required of the system when the motor creates more heat, or the ambient temp is higher, it causes the problems you have described.

cheers, let us know how you get on.

T

I just realised the radiiator that I have I had its core replaced last year and retained its original top and lower sections of radiator so its a non genuine core fixed to the older upper and lower sections of the previous older radiator. i forgot how many cores/rows it has. Is there a way to check on how many cores does it have? How many cores are recomended for extreme hot climate?

Thank you so much... Will start working on this tomorrow

Your assessments were correct.. the 4 core radiator was blocked and got this cleaned....

Also came to know that the clutch fan has been made direct from the engine.. Assume this should be OK?

I got the radiator rodded out and cleaned out the condenser ... did a test drive at 95 to 100 km/hr in approx 42C+ and noted temperature started going up by more than 50%... I am assuming if i drive in 45C+ environment its engine likely to heat up

The thermostat is not present so assume that should be ok i guess and the clutch fan is direct

Dissapointed to learn that 2H engines heat up at high temperatures of 45C+ with AC on... although i recently overhauled my engine few months and it should have worked like new.

I am determined to fix the problem unless if there is generic fault as the post says 2H engines will definately heat up with AC in high temperature environments of 45C+ at speeds of 90 to 100 km/hr.

I probably need to go through a set of checklist again carefully incase if i have missed anything out...

1. To look for gaps in fan shroud and seal it if any found

2. To check the fuel system on over fuelling and whether its is running lean. Need to show this a good diesel fuel system specialist

3. Will do a CO test,. i am guessing my head gasket is fine otherwise it would still heat at any temperature environment?

4. Need advice what type of coolant shall i put and what is the right mixing ratio?

5. Was told by a friend of mine to shift AC condenser from the front to someother place within the undercarriage cavity as it blocks the radiator. I think my condeser isnt original . Is this really workable?

6. Do i need to check compression numbers by cylinder ?

Is there anything else that i should add to the list?

I wanted to carry out a compression in every cylinder, what should be its correct combustion pressures in psi that are going to force the gasses into the cooling system