Hot 300tdi

my 300tdi got cooked. I placed the cause down to a leak in the coolant and blown head gasket along with breaks being locked on.

Just put a 300tdi in from a disco. No known issues...

Along with new radiator, thermostat, coolant hoses and water pump.

Ran the engine for the first time and within 20mins of sitting at idle, the temp guage is at red, pipes and engine are hot.

Checked coolant and squeezed each pipe to make sure they have air, but no change.

Thoughts?

did fan start to make a noise as temp rose and it locked up,id go for a trip of a few miles and get some air through the rad

Air lock or something else. A Tdi will sit all day running and barely move on the temp gauge. They only run hot when being worked.

I assumed when she was sitting at idle, the fan shouldn’t really have a need to go on?

Should it really get that hot just sitting there?

Keep checking and squeezing pipes, but can’t seem to get any air out.

Rorie said:

I assumed when she was sitting at idle, the fan shouldn’t really have a need to go on?

Should it really get that hot just sitting there?

Keep checking and squeezing pipes, but can’t seem to get any air out.

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weres the heat going to go ?run it too long like that and youll boil the sump oil

So what’s the best way to get air out?

I haven’t moved the car for that very fear!

Rorie said:

I assumed when she was sitting at idle, the fan shouldn’t really have a need to go on?

Should it really get that hot just sitting there?

Keep checking and squeezing pipes, but can’t seem to get any air out.

Click to expand...

Still say something is wrong, maybe pull the thermostat and try it without. Double check you have plumbed it all in correctly and check for other obvious signs.

Might be worth trying to rig up some other way of checking the temp rather than the dash gauge. The engine will feel warm, but the gauge could be faulty.

An air lock is still a possibility too.

For reference I run a 200Tdi in my Series with a Disco rad. And only an electric fan, no viscous fan. The only time I need to turn the fan on is when green laning or off roading in low range. Tick over/idle it never gets warm enough for the fan.

Rorie said:

So what’s the best way to get air out?

I haven’t moved the car for that very fear!

Click to expand...

have you undone the 2 bungs on on top of thermostat housing the other on rad top you must fill with both open and both must overflow, if youve done that its not air locked, and a run down the road is good for shifting air locks

Rorie said:

So what’s the best way to get air out?

I haven’t moved the car for that very fear!

Click to expand...

Depends where the air is.

You could try filling from the heater pipes in both directions until you get water out. There is a bung in the top of the rad you can also remove to let air out and pour additional water in from.

if heater hoses and top hose etc all get hot it hasnt got an air lock, the hot top hose shows thermostats opening too

Yeh opened the rad top plug and it overflowed. Same with thermostat plug.
Top hose is also hot. Thermostat housing is too hot to hold on to...

Also stuck my finger in the header tank water, it’s not hot, it’s warm.

I was testing the engine without my fan as I never thought it would need the fan at just idle, as noted above. But my new electric fan has a separate inline thermostat in the top hose, so just wired that up. Lowest setting is meant to be 70 degrees. Fan isn’t on yet and temp guage in cab is almost at the end of the white...

So, fan wouldn’t come on at all.
Bypassed the relay for it and it does work.
Took bleed screw off thermostat housing and stuck a digital thermometer in- 65 degrees. So this explains why the fan isn’t coming on.
Top hose is hot, so does this mean the thermostat (original in line one) is working?

If there is a fault with the gauge, how would I test this? There is obviously no temp markings on it to work out what temp corresponds to the needle.

Or could something else be a miss?

Just a thought is the sender the same?
Disco engine in a defender?

J

marjon said:

Just a thought is the sender the same?
Disco engine in a defender?

J

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Haha, same, or faulty.... I remembered I had a spare used one. Temp is now showing less than 1/3 the way up the white. With the thermometer test and the new fan all aligning, I think I can trust this one!

Thanks for all the help!!