Overheating problems

[RAB]

Rab here.
I have a 1994 3.0TD Auto, fantastic machine, with one exception, general travelling at up to 75 MPH the temperature gauge stays dead centre, but if I push it a little harder on a long distance journey, especially if the motorway is on a slight incline pushing all of it's 2 tonne at speed, the temp gauge all of a sudden starts to climb towards the red. Does anyone have a solution to this problem, other than slowing down? Brand new Radiator and thermostat fitted, still no change. Please help!!!!!!!!!!

[TonyN]

If you've done the rad and the stat, I'd check the viscous fan is working OK, did you put the fan shroud back on?

Have you checked the water level lately? Could have some air in it.

Rab here.
I have a 1994 3.0TD Auto, fantastic machine, with one exception, general travelling at up to 75 MPH the temperature gauge stays dead centre, but if I push it a little harder on a long distance journey, especially if the motorway is on a slight incline pushing all of it's 2 tonne at speed, the temp gauge all of a sudden starts to climb towards the red. Does anyone have a solution to this problem, other than slowing down? Brand new Radiator and thermostat fitted, still no change. Please help!!!!!!!!!!

[Tallyman]

I had some overheating on mine last year. Two things helped. First was fitting a second ATF oil cooler. The inbuilt one is in the bottom of the rad, blocks off the outlet pipe somewhat, and can re-heat the cooled water before it goes back into the engine if the ATF is working hard. Second, as Tony N mentioned, check that the viscous fan is working properly. Mine had almost no oil in it. Topped up and not had any problems since ("touching wood" on computer desk as I'm typing this!!!).

[da SLUG man]

have you checked the ATF fluid?... often overlooked and probably black as a black thing!...


should be red and be between the max and min marks

[mud skipper]

I had some overheating on mine last year. Two things helped. First was fitting a second ATF oil cooler. The inbuilt one is in the bottom of the rad, blocks off the outlet pipe somewhat, and can re-heat the cooled water before it goes back into the engine if the ATF is working hard. Second, as Tony N mentioned, check that the viscous fan is working properly. Mine had almost no oil in it. Topped up and not had any problems since ("touching wood" on computer desk as I'm typing this!!!).

mike
when i had my rad off at the weekend i couldnt see how you get oil into the viscous fan, i see it splits in two but not how i could top it up , any help please my fan has some resistance when cold but two minutes of running no restance hardly, is this normal
john

[NiftyNev]

This makes interesting reading.

http://toyotasurf.asn.au/forum/viewtopic.php?t=195

Neville

[da SLUG man]

mike
when i had my rad off at the weekend i couldnt see how you get oil into the viscous fan, i see it splits in two but not how i could top it up , any help please my fan has some resistance when cold but two minutes of running no restance hardly, is this normal
john

you gotta strip it down to replace the oil...
yeah that's what should happen... the clutch bites as it gets hot... so the hotter the engine, the more fan you get

[NiftyNev]

fan has some resistance when cold but two minutes of running no restance hardly, is this normal
john

It's normal for the fan to have less resistance when the oil in it has warmed slightly and distributed evenly in the housing.This means the engine is using less power to turn it.As the engine gets hot the heat is absorbed by the viscous coupling and reaches a stage where it turns more and eventually lock up for a short time.This only happens rarely on mine because the cooling system is working so well.Take it for a good hard run and see what happens.By this I mean up a few steep hills or a tough course. At high speed it won't get hot enough because of the large amount of air flowing through radiator.

Neville

[mart 870]

A viscous fan will only really work upto speeds of about 35mph, after that air flowing through the grill from going fast is far great than what the van can kick out.

Mine used to overheat at speeds of above 100mph but removing the internal cooler and putting a new rad cap on sorted it. My rad cap got that bad that when the engine was cold i could pull the overflow pipe from the expansion bottle and if i revved the engine water would come out of the pipe.

[marky]

A picture of the inside of the Viscous fan clutch assembly.

[fatfires]

Things I'm trying

A picture of the inside of the Viscous fan clutch assembly.

I had a problem, found the cause in the bore (nother story) however because I tow I have taken the following precautions and so far..reaching for wood...they appear to be working
1 changed stat to a 76' c one
2 had rad recorred with a 3 row high efficiency one had a custom bigger bottom tank made, got rid of the outlet blocking ATM oil cooler, had it replaced with one from a Landy turbo 90 that sits clear of the outlet
3 run it with premix coolant
4 split the fan coupling and added 1 tube of silicone
the engine now runs cooler than previously, but I dont know whether this is due to the engine rebuild or not, because the engine was well tight I was expecting it to run a bit warm but all is fine
My reasoning for the mods was if it works for the ausies and their article made sence to me as a heating engineer...got to be worth a go!!
best of luck
Tony

[mud skipper]

I had a problem, found the cause in the bore (nother story) however because I tow I have taken the following precautions and so far..reaching for wood...they appear to be working
1 changed stat to a 76' c one
2 had rad recorred with a 3 row high efficiency one had a custom bigger bottom tank made, got rid of the outlet blocking ATM oil cooler, had it replaced with one from a Landy turbo 90 that sits clear of the outlet
3 run it with premix coolant
4 split the fan coupling and added 1 tube of silicone
the engine now runs cooler than previously, but I dont know whether this is due to the engine rebuild or not, because the engine was well tight I was expecting it to run a bit warm but all is fine
My reasoning for the mods was if it works for the ausies and their article made sence to me as a heating engineer...got to be worth a go!!
best of luck
Tony

thanks again guys for the advice reading the ausie bit made sense, dangerous to run it to cool as well as to hotso far i have a modifyied rad a new cap a new stat left to do is an atf cooler and viscuos fan top up if this cures it then you guys will be the second to know
cheers again
john

[RAB]

Rab

Where can I get an additional engine oil cooler from in Sussex and how much do they cost? Would this make that much difference to the engine temperature at higher speeds? Same with the Viscous fan oil? Is it advisable to remove the ATF oil cooler BLOCKAGE in the base of the radiator? More ideas please for over heating at higher speeds. As I have mentioned before I have already replaced the radiator and the thermostat. HELLLLPPPPPPP!!!!!!!
RAB. Primo surf man.

[fatfires]

Where can I get an additional engine oil cooler from in Sussex and how much do they cost? Would this make that much difference to the engine temperature at higher speeds? Same with the Viscous fan oil? Is it advisable to remove the ATF oil cooler BLOCKAGE in the base of the radiator? More ideas please for over heating at higher speeds. As I have mentioned before I have already replaced the radiator and the thermostat. HELLLLPPPPPPP!!!!!!!
RAB. Primo surf man.

Hi
silicone oil is a toyota part, part numbers I got from ausie site, they were ex central stock UK so took 2 days to branch, there were 2 different ones I took the stock one and it was cheaper by about a quid - dont know why but can only assume UK speck and other was Jap? spec. Easy job to do, impact driver helped to start screws and didn't have any probs with the o ring as they sugested on site
mine is still going OK, not running too cool with the change of ATF cooler and tank seems good
hope this helps
Tony