Thread: Radiator problems (Coolant refill) Discovery 1 (300 Tdi 97)

I thought I would replace my coolant today, looked on the forum, did every thing you guys said to do, I mean every thing. taken for a drive three times and temp sits at normal for 3 or so minutes then as quick as a flash up goes the temp gauge, (water gauge), in the past the temp has risen slowly and down slowly under extreme hills or speeds, but this is like quick and then would go up then down in small increments but quick.
I undid the over flow cap hoping it would let out the air but made no difference, the car does not appear to be any hotter than normal, by smell or by steam, only the gauge is saying that it is hot, really hot.
suggestions please

I recently put a new head on my TDI(3 weeks ago). My manual says to fill through the top of the thermostat housing. I found that as it was higher than plastic overflow tank, that the coolant was slowly going to overfill this. This was fixed by putting the cap back on the expansion tank. After this I just filled until thermostat housing was full and ran engine until warm. I then let it cool, and topped up at thermostat again. I did this about three times and all is good. I have a low coolant alarm in the top of the thermostat housing and I have now fitted a TM4 engine watchdog.

As for running the cabin heater. As some one said in an earlier post, there is no heater tap so it will make no difference.

Dave.

having the heater on isnt so much to "purge" the heater any more.

Its to ensure that you are getting coolant flow through the heater. In the TD5 deefer the high point of the cooling system is the heater hoses.

The heater lines for a tdi And the td5 disco all exit the highest part of the cooling system. odds are if youve stripped it and drained it if your going to have a big air bubble in the system thats where its going to hide.

Originally Posted by Mr Whippy

I recently put a new head on my TDI(3 weeks ago). My manual says to fill through the top of the thermostat housing. I found that as it was higher than plastic overflow tank, that the coolant was slowly going to overfill this. This was fixed by putting the cap back on the expansion tank. After this I just filled until thermostat housing was full and ran engine until warm. I then let it cool, and topped up at thermostat again. I did this about three times and all is good. I have a low coolant alarm in the top of the thermostat housing and I have now fitted a TM4 engine watchdog.

As for running the cabin heater. As some one said in an earlier post, there is no heater tap so it will make no difference.

Dave.

Using this method - after you have finished topping up, how full is your expansion tank when cold ?

thks

I am having the same issues as most peeps here, with cooling problems, (water leaving a perfectly good motor and migrating to the expansion tank where it leaves via the cap valve) I am a retired auto engineer with heaps of car experience, and the whole cooling circuit of tdi's has me bewildered. I am running with no thermostat trying to eliminate each fault one at a time, but it is still happening. I have checked for exhaust in cooling system, flushed the system etc etc I am about to remove the hose and check the impeller in the pump, but it sure has got me perplexed. did someone mention rubber impeller?? or was that a typo?

Coke bottles??? Lifting the coolant tank?????
WTF???????? I have never had a problem filling the system
As per the factory manual instruction. Why do people
Feel the need to make things hard for themselves

Originally Posted by Linds

Using this method - after you have finished topping up, how full is your expansion tank when cold ?

thks

I apologize for not replying to this post. I was away on holidays.

I filled through thermostat housing with expansion cap off until the expansion tank is about correct level.

I continued filling through thermostat housing as I described earlier. After a few runs, check expansion tank when cold and top up to correct.

It is now 18 months and I have had no problems.