Thread: Tdi 300 overheating problems/mystery

The trouble first up I would say thermostat but you replaced it,it boiling for sure if the coolant is bubbling so that means the gauges are working,how soft-old are the rad hoses?,it is not happening all the time which means alot of the common faults like blocked core can be ruled out as they would cause the problem to happen regularly so a colapsed hose would be were I would start.Is the motor using coolant?. Pat

Where are the earth connections for the black box alarm? I have seen poor earthing in Defenders cause temp gauges to go right up into the red, when engine isn't actually hot. Did it feel like it was boiling? how much pressure was in the system? The top hose usually won't be full of coolant, expect it to be about half full as it is slightly higher than the coolant bottle. The bubbling may have just been because it was at operating temp. When it was getting hot, was the heater still working? and how is your viscous fan hub?

I am leaning toward an electrical fault still, try adding an extra earth lead from the battery neg to one of the seat box bolts, and see if it still does it.


Sorry for all the questions
JC

Gentlemen,
thankyou for the advice. I went out this morning and checked over a few things such as all of the hoses and belts (new less then a year ago) and also took out the new thermostat and put it and the old one into a pot of boiling water. The new one opened up but the old one is definately buggered. The earthing for the alarm system seems fine as well. The temp sender wire was recently covered in heat shrink and then put in split tubing as it had worn through and was effecting the temp gauge. My mechanic mate now thinks it may be the viscous fan thats causing the problem as the vehicle runs fine as long as I don't stop and let the motor go back to an idle. He thinks that the fan doesn't get back up to speed after i take off again and this is causing the motor to overheat. It seems to make sence to me as well. I am going to go for a run shortly and see if I can see a difference in the fan speed if I do stop for a bit after the motor has reached running temp. Any tips on definatively identifying if a viscous hub is had it or not?
cheers
dave

[QUOTE=justinc;1068300]Where are the earth connections for the black box alarm? I have seen poor earthing in Defenders cause temp gauges to go right up into the red, when engine isn't actually hot. Did it feel like it was boiling? how much pressure was in the system? The top hose usually won't be full of coolant, expect it to be about half full as it is slightly higher than the coolant bottle. The bubbling may have just been because it was at operating temp. When it was getting hot, was the heater still working? and how is your viscous fan hub?

I am leaning toward an electrical fault still, try adding an extra earth lead from the battery neg to one of the seat box bolts, and see if it still does it.


Sorry for all the questions
JC[/QUOTE

Gidday Justin,
Mate I have taken your advice from a previous post and put in an extra earth lead ages ago. I am pretty sure that the heater was working when I got home and it was definately bubbling in the expansion tank. Any suggestions on how I check the viscous fan hub would be gratefully received.
cheers
Dave

check this out Td5 viscous fan coupling stuffed?, I too think there is something wrong with your viscous fan. The stop in traffic will stop the natural airflow and need the fan to pull the air through. When the viscous fan engages you will know it as it makes a bit of noise as it pulls one hell of a lot of air through. It sounds like a small plane .

although the thermostat not working is an issue that clouds the waters but given that replacing it did not solve the problem I will stick with the fan as the culprit.

Did you refill the cooling system through the plugs? could you have induced an airlock?

Originally Posted by slug_burner

check this out Td5 viscous fan coupling stuffed?, I too think there is something wrong with your viscous fan. The stop in traffic will stop the natural airflow and need the fan to pull the air through. When the viscous fan engages you will know it as it makes a bit of noise as it pulls one hell of a lot of air through. It sounds like a small plane .

although the thermostat not working is an issue that clouds the waters but given that replacing it did not solve the problem I will stick with the fan as the culprit.

Did you refill the cooling system through the plugs? could you have induced an airlock?

Gidday Slug burner,
mate I actually found your thread after I posted the last message and have just come back from a drive with the humble 2 inch paint brush. I stopped after 1km and used the brush to try and stop the fan and lo and behold it did. I then went for a longer drive staying in 4th gear to try and heat the motor up and stopped again and again the brush could stop the fan. I turned the vehicle off and waited for about 10 minutes and then took off to see if the vehicle would overheat but the temp needle stayed just left of centre all the way. I tried this a couple of times but of course Murphy's rules ensured thaqt the car stayed nice and cool and each time I could stop the fan with the brush using a moderate amount of pressure.
So, where to from here? I am guessing that if the viscous fan is properly engaged it would be unable to be stopped or at the very least extremely diffcult to stop, is this correct?
Yes I did fill the system through the thermostat plug, nice and steady and checked the level in the expansion tank a couple of times before I took off on the test drive. I am letting it cool down now and will check it again in an hour or so. mate I was trying to hear the noise you reckon the fan makes but with all the rattles the old truck makes now I can't even hear a passenger right next to me in the front seat let alone a fan in the engine bay.
cheers
Dave

Have you tried removing the front grill when at temp and putting your hands on the radiator to see if there is differences in temp?

we had reoccuring problems with our 200tdi we changed everything still had it bled the system so many times...it ended up being our radiator that was pulled 6months before along with our disco radiator and neither of them had been rodded like we asked and paid for ...when the garage we took it to after cleaned the radiators they also said that not only was it blocked and had not been cleaned like suggested that a reasonable portion of the radiator was also starting to tire and brake down.

Mate throw a falcon fan on it,straight bolt on fit and less than $50 from the wreckers.Buy the complete unit,they pump more air than LR units. Pat