Thread: 300TDI overheating issue?

See here for Dave's method

the coke bottle cooling system fill.

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

Originally Posted by Fausto79

Check the barbs on the ends of hoses going from matrix to engine bay. Mine were shot so I bypassed matrix. How old is engine? Do you have any history? I would honestly check the heater matrix before connecting up a new head to it. All it needs is one little pin hole n slowly it opens up and you lose coolant.

Most importantly of all, as you do all this work and fix head gasket, get a low coolant alarm NOW and fit it as part of the work. 300tdi should not run without one. EGT gauge useful too but not as crucial as low coolant alarm. Order it right NOW. Don’t delay. It’s a head saver.

PS check block for warping too. I think anything under 5thou acceptable but don’t quote me on that number. Skimming head not advisable. Make sure you get correct size elring gasket (check for number of holes on yours) there’s a tab sticking out i think on IP side of engine.

Originally Posted by cripesamighty

See here for Dave's method

the coke bottle cooling system fill.

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

No history on the vehicle what-so-ever! But have been assured by mechanic if the head is usable then facing it will be fine and if the heater matrix isn't good he'd get it sorted. Have gone and ordered a low coolant alarm today! Should arrive on Friday and hopefully will be in just as the car is fully sorted.

I think he said he only wants to use elring gaskets too.. So there's a plus.

Thanks Cripes! Will have a look now!!

Originally Posted by oddsoul

Thanks for everyone's help!

Found out that the thermostat is actually starting to crack open at 90c and purchased a new one and it was opening at ~80c!

They are supposed to start opening at 88 C so the old one was working perfectly.

Originally Posted by Red90

They are supposed to start opening at 88 C so the old one was working perfectly.

From what i've read and been told. They should be opening between 82-88c

according to RAVE: 85-89°C

but they all vary I guess. I imagine tolerances need to be factored into the equation too.

My waxtstat barely opened at 88
Tridon closer low 80's, hard to measure exactly but 82°C was an average.

My assumption tho is that the waxstat was probably just old, and with age they change their characteristics a little. still have mine and it's not gummed up or rusted, but definitely old looking.

No. 88. Thermostats are basically an on/off valve. 88 is the spec and the spec always refers to initial opening temperature.

Originally Posted by Red90

No. 88. Thermostats are basically an on/off valve. ....

Sounds good in theory, but the reality is different.
They open and close gradually.

My Tridon is a 190 model(190°F) marked on the body and packaging. (87.78°C)
I also got a 180 model(82.22°C) too.

As already said, the 190 started to open at about 82, and was fully open at 88.
The 180 model stated to open at about 76-ish, and fully open at 80°C.

While it was in the tub of hot water, I'd add some cold, and it took longer to close up, than it took to open up .. so there was a delay in closing compared to opening.
I'd guess that was down to a reaction time.
But once at 75°C it was closed again.

Waxstat was much slower to react in all situations heating up and cooling off tho.

I've had the Tridon now since about Jan-Feb, and for all intents and purposes the coolant temp, via the VDO coolant sensor, reads steady @ 80-83, which corresponds with what I saw in the bucket of water testing prior to fitting.

You are mixing up time and temperature. It takes time for the wax to melt and freeze, but it melts and freezes at a very specific temperature, not over a range. That is the whole point of using a wax motor.