Thread: TD5 dont trust the temp gauge

Hi Simon
The correct way is to remove the bleed screw,unclip the reservior(gently pull up on the filler end then it unclips,slide out of bracket) loosen cap and lift,coolant will spurt out the bleed.Re-fit bleed screw whilst its leaking.DO NOT OVERTIGHTEN BLEED SCREW,then re-fit reservior.
Goodluck
Andrew

Hi all,

Sorry to drag an old thread up to the top again but I'm having a dilema with my Td5 Defender.

Since orning her, I've had to top up the coolant from time to time.
The outside of the expansion cap always seemed to be damp.
During a recent trip, I stopped after a long motorway run and had coolant leaking past the cap. The temperature gauge was in the middle and had not moved.

I purchased a new cap and topped up the coolant (with water as I couldn't get any of the correct coolant at the time).

Since this episode, she's been running well and after a small drop, the level of the coolant has been constant.

However, on a recent run, I plugged in my new Nanocom and was terrified to see a coolant temperature of 106 degrees (along with a flashing red light on the front of the Nanocom!) At the time i was doing around 65 miles per hour. I slowed down to 45 and the temperature dropped to around 88 degrees.

I'm about to back flush the cooling system, change the thermostat and put in some fresh coolant. I'm doing this mainly for my own peice of mind.

My question is...
What coolant temperatures should I see on my Nanocom, at idle and when under sustained load/speed?, (assuming that my engine is in good health)

Originally Posted by Frenchie

I'm with you Andrew, that stupid gauge effectively cost me a head.

When it overheated the gauge stayed in the normal position then would shoot immediately off the scale, engine cuts out, cools down, gauge goes back to normal, engine restarts and the cycle starts again. This behaviour made me think it was an electrical problem so I drove over 1000km with the motor overheating.

I now have a low water sensor, a block temp sensor and the nanocom. I like to know exactly what is happening in there.

Do you think if you had the low coolant alarm installed before you overheated the first time, you could have saved the head?

It is a fact that the temp gauge will only work as designed when there is sufficient water in the cooling system. Therefore, detecting low coolant at an early stage will reduce catastrophic overheating due to lack of coolant.

Even during the worst case scenario where the engine overheats (120 DegC+) due to a reason other than lack of coolant, a hose may burst or the filler cap will release coolant to a point where the low coolant alarm will sound.

What does the driver do when the audible alarm sounds? pulls over to check what's going on. Without the alarm, the car could be driven until it is well and truly cooked, drivers are generally oblivious to any problem until the car either misses, stalls or even seizes.

I’ve been there. I am now a firm believer in early warning systems.

Cheers

can any one tell me what their td5 does when you disconnect your coolant sensor wiring, while running and at operating temp, trying to diagnse a faulty sensor ,TA

Originally Posted by jmkoffice

Do you think if you had the low coolant alarm installed before you overheated the first time, you could have saved the head?

The overheating wasn't caused by low coolant, it was caused by the radiator being externally clogged with mud. My fault I had been slack in cleaning it after a winter of mud plugging. Learnt an expensive lesson there!

The problem was, because of the really strange behaviour I didn't think it was overheating, I thought the gauge was faulty or it was another electrical problem, so drove from Perth to Exmouth and back

I guess I was lucky it didn't explode! (The computer making it cut out at least saved it from seizing).