Running hot under load!

Hi all,

My wife and I are currently in mexico doing the panamerica and have had an overheating problem since west grand Canyon. I've never let it run into the red so far but it's gotten dam close and it appears that it only happens under load e.g. climbing long hills.
I've replaced the thermostat, the engine has been flushed, the rad cleaned, and a 70/30 mix added. I've been told that the clutch fan is in good working order (though I don't think it was fully tested), and the water pump is doing its job.

I should mention that the defender is 20 years old, we aren't towing anything though we are quite heavy ( see photo: https://flic.kr/p/GyiZnA) probably over 200 kg on the roof alone not to mention the inside completely built out with couch/bed and lots of storage space.

I also fitted an allisport full sized intercooler in front of the rad.

So long we were travelling in cooler climates, Canada and the USA all was good even going up long hills, but here in mexico we can't drive the long hills like we did in the north without the temp going up over 3/4's. I did a test drive yesterday after the engine was flushed and brought a temp pistol with. I stopped just before it red-lined and checked the temp to make sure it wasn't a faulty sensor and it read 113 C (235 F) which I have read is pretty damn hot.

A minute or two idling at the side of the road is enough to bring the temp back to normal.

So to the question (s)

What should I do now? Convert to an electric fan or replace the viscous fan anyway? Uprate the rad? Or simply take the hills slower and not over tax the motor?

Thanks for any advice

Gary
www.adventure-continued.com

IIRC, a good way of testing the viscous coupling is with a rolled up newspaper - warm the engine up so the coupling should be a solid coupling, and, taking appropriate safety precautions, and being very careful, try and stop the fan with the rolled up newspaper - you should now have a very shredded newspaper - if the paper survives, the coupling is junk.

Taking the hills slower should work, but if the coupling is kaput, you might need to go too slow for comfort.

Hi disco1bfg,

Thanks for the tip I will give that a try...

Cheers from oaxaca

Gary Gilbert said:

Hi disco1bfg,

Thanks for the tip I will give that a try...

Cheers from oaxaca

Click to expand...

No probs - do a search - it'll show up as a bit of a regular

Yeah I've seen a lot of threads in a lot of different forums and there have been problems from thermo to fan to cracked heads to a timing issue... though I hope to god that if I had a cracked or warped head I would be able to tell with how it's running, what's coming out the tailpipe or what's showing up in the oil (unless of course it's all a lot more subtle than that)

Ive read that some folks who got a full size intercooler also got a larger and thicker rad, which tells me that there must be issues with cooler capacity in some applications...

Cheers
Gary

Gary Gilbert said:

Hi all,

My wife and I are currently in mexico doing the panamerica and have had an overheating problem since west grand Canyon. I've never let it run into the red so far but it's gotten dam close and it appears that it only happens under load e.g. climbing long hills.
I've replaced the thermostat, the engine has been flushed, the rad cleaned, and a 70/30 mix added. I've been told that the clutch fan is in good working order (though I don't think it was fully tested), and the water pump is doing its job.

I should mention that the defender is 20 years old, we aren't towing anything though we are quite heavy ( see photo: https://flic.kr/p/GyiZnA) probably over 200 kg on the roof alone not to mention the inside completely built out with couch/bed and lots of storage space.

I also fitted an allisport full sized intercooler in front of the rad.

So long we were travelling in cooler climates, Canada and the USA all was good even going up long hills, but here in mexico we can't drive the long hills like we did in the north without the temp going up over 3/4's. I did a test drive yesterday after the engine was flushed and brought a temp pistol with. I stopped just before it red-lined and checked the temp to make sure it wasn't a faulty sensor and it read 113 C (235 F) which I have read is pretty damn hot.

A minute or two idling at the side of the road is enough to bring the temp back to normal.

So to the question (s)

What should I do now? Convert to an electric fan or replace the viscous fan anyway? Uprate the rad? Or simply take the hills slower and not over tax the motor?

Thanks for any advice

Gary
www.adventure-continued.com

Click to expand...

check rad gets hot all over once up to temp

Gary Gilbert said:

Ive read that some folks who got a full size intercooler also got a larger and thicker rad, which tells me that there must be issues with cooler capacity in some applications...

Click to expand...

My 300Tdi has a full width intercooler, and is tuned to 145 BHP. The limiting factor for me is EGT I can get up to 600C, at which point I ease off, as forum knowledge seems to be that the head will not be happy at 700. Obviously ambient temps are much lower here, and you might be more water limited than I am, so to speak

jamesmartin said:

check rad gets hot all over once up to temp

Click to expand...

Which Is why the above idea is a damn good one

Here in mexico they too the rad apart and cleaned all the tube out so no blockages

Gary Gilbert said:

Here in mexico they too the rad apart and cleaned all the tube out so no blockages

Click to expand...

its not just blockages with a 300 tdi rad its the baffles inside,with in and out pipes been on the same side

is that 70/30 mix. Is the 70 water or antifreeze? Did you put a new radiator cap on it? How is our air filter, how new is it?

jamesmartin said:

its not just blockages with a 300 tdi rad its the baffles inside,with in and out pipes been on the same side

Click to expand...

OK thanks will check it out

Thor1950 said:

is that 70/30 mix. Is the 70 water or antifreeze? Did you put a new radiator cap on it? How is our air filter, how new is it?

Click to expand...

70 % antifreeze, no didn't put a new cap though it's holding it's pressure as far as I can tell, air filter is 4 days old.

Going to be going back to the shop tomorrow and test the clutch fan and a few other things before trying to see about getting the old rad recored longer and with 4 cores instead of the 3 that it has now...

New thermostat, new oil, new filters, flushed engine and rad, had a new thermometer but ordered the wrong one (green instead of black) may install an external...

Will see what the guy says after testing the system, he was more keen on testing than wasting all the money on a new rad when it may not solve the issue which speaks volumes about him.

Will let you all know what the results are

Gary Gilbert said:

70 % antifreeze, no didn't put a new cap though it's holding it's pressure as far as I can tell, air filter is 4 days old.

Going to be going back to the shop tomorrow and test the clutch fan and a few other things before trying to see about getting the old rad recored longer and with 4 cores instead of the 3 that it has now...

New thermostat, new oil, new filters, flushed engine and rad, had a new thermometer but ordered the wrong one (green instead of black) may install an external...

Will see what the guy says after testing the system, he was more keen on testing than wasting all the money on a new rad when it may not solve the issue which speaks volumes about him.

Will let you all know what the results are

Click to expand...

Good luck and have a safe trip. I would consider replacing the radiator cap. I had a slight getting warm on my diesel cap did hold a little pressure, but not spec. replaced the cap and temps dropped. Caps are cheap.

What do you mean green and black thermometers?

In a pinch to get you out of a jam in an emergency you could take the stat out completely? Engine would run very cool then, cooler is better than to hot imo

If need be open the windows and put the heater on fully hot and max fan speed, that should help dump some heat out of the engine. I don't think antifreeze is as good a heat conductor as water so 70:30 may not be as good as say 30:70 (you still need the ant-corrosion properties of antifreeze but if it isn't freezing you might be able to improve the water ratio). Either way you probably still have an issue somewhere, either remove the stat and see what happens or change / recore the rad if it is still the original one.

Kwakerman said:

If need be open the windows and put the heater on fully hot and max fan speed, that should help dump some heat out of the engine.

Click to expand...

+1 - I used to have to do that with a Triumph Spitfire, and thats in our climate!!

Kwakerman said:

I don't think antifreeze is as good a heat conductor as water so 70:30 may not be as good as say 30:70 (you still need the ant-corrosion properties of antifreeze but if it isn't freezing you might be able to improve the water ratio).

Click to expand...

This is my understanding too it has been covered on the forum before, often gets included in any discussions about waterless coolant.

Kwakerman said:

Either way you probably still have an issue somewhere, either remove the stat and see what happens or change / recore the rad if it is still the original one.

Click to expand...

+1, sadly rads don't last forever. - if you get a re-core, have a nosy at the baffles, to see if they were kaput, and let us know please