300tdi temp problems/water not heating

Well I don't think water is circulating around my 300tdi
Went from Blackpool to Sheffield with a 19ft car trailer yesterday. Temp sat in the middle all the way. On the way home after around 200 mile felt a little down on power. Pulled in at the services to have a look In the engine bay.
All hoses ok no pressure and only just worm. Felt the rad it was cold, water in header tank was also cold, cold like the car had not been used,
my thinking is iv just done 200mile water should be hot !!!
Did the last 30 mile home no problems, heaters blowing hotish air out

So what do you think ???

The rad is a new one 12 month ago. Not used off road, no loss of water from what I can tell

i would take the thermostat out and boil your kettle and stick it in the water and see how far it opens thats the first thing to check and are you hoses hard you could have a leak not alowing your water the pressurise and get to running temp.

also take your aux belt off and spin the water pump.

Sounds like the thermostat is missing or stuck open ? You could be a little low on coolant as 300tdi are prone to air locks if not filled up properly, but as you have liquid in your header tank it should not be that. Check the level with the engine cold.

Towing in this country should not cause your car to overheat and a temp gauge in the middle sounds fine to me. Most cars in good condition the gauge is less than half way up during normal driving.

What kind of radiator is it ? as I have fitted a new one to mine as the old 4 core one leaked and the new Nissens 3 core is more efficient than the new 4 core I fitted 4 years previously !!

Regards

Jonathan

jonathanp said:

Sounds like the thermostat is missing or stuck open ?

Click to expand...

If it was stuck open then the rad and coolant bottle would be warm as the water would be circulating. Either the stat is closed or the water pump has died. My guess would be the stat as if it was the pump heat would still travel a bit through the coolant and the outlet pipe would be a bit warm IMO.

+1 with Tuskenraider.

+2 on that one.had a similar problem pulling the tin tent down to norfolk.took the thermastat out and replaced it. problem sorted.



ron.

I do not understand if the thermostat is stuck closed on a 200 mile trip towing a car trailer, that means the engine is not getting cooled down, so why has it not boiled over ?

Regards

Jonathan

Take the stat out ! If there is one ! Boil kettle , hang stat in water as it boils if it doesn't move then its broken!! Your pump impeller may have fell off !! Your head gasket may be failing !! Why not have a mechanic check it over and save yourself a load of hassle !!!

Basic physics:
Heat = Work

The more work the car does, the more heat it generates.
Diesel engines generate less heat for the useful work they do but they still generate it in proportion to the workload.

That heat MUST go somewhere.

If you're cruising at 60mph (legal max. with a trailer) with not much of a load on, it's not actually working all that hard.

There is an awful lot of air space around a TDi engine and that dissipates heat.

Had the heater on? That's a mini-radiator right there.

Keep an eye on fluid levels, watch the temp gauge and if the gauge is showing and you can't get heat out of the heater, you're low on water.

Other than that, take it for a thrash round town, stop it with the engine running and try the radiator / top hose then. (DO NOT OPEN ANY CAPS, of course!)

Others are right here: closed stat, duff pump or coolant loss usually show as overheating.
Open stat shows as overcooling but rad will be warm.

I had a problem where mine got up to temp very quick and I found the previous owner had installed a cheepo plastic water pump,

If I tow the caravan with my foot down flat it gets hot, think my rad is a bit blocked with mud and my winch is blocking a big part of my rad, steady away tho with a caravan is fine, no trailer and the temp is always at half way.