Overheating Turbo Diesel (not Tdi)

[Mark Jenkins]

I have an overheating problem with my 1989 engine. It runs OK at town speeds but on longer hauls at speed it pushes into "Hot" and then if speed is maintained starts to nudge the red zone, forcing me to slow down. At 50, although the temperature holds "Hot" not "Red", it won't cool down properly until it is completely idle or switched off.

It's not leaking.

It has a new thermostat, a new temp sender and a new water pump.

The fan works well.

It hasn't blown a gasket and the engine has plenty of power.

This seems to leave the radiator, which has clear vanes and has been flushed and back-flushed out of the vehicle with a hose and is running clear water through it.

Does this still point to a blocked radiator core? I am prepared to replace it if necessary.

Are there any chemical remedies like radiator or engine flush you think might be worth a try?

Mark

[white90]

on my 2.5 N/a

it would get very hot, the rad was blocked even after back flushing

I purchased a new radiator that sorted it along with a decent fan when offroad

[steve b]

Hi Mark , blocked rad like what white 90 said . Have you felt rad tubes when gauge says hot? if its blocked you'll find cooler patchs indicating blocked sections. worth checking the viscous fan coupling altho this time of year its not hot enough to make any difference tbh.

cheers

Steveb

[Happyoldgit]

I'd suggest the rad too, it can still be partially blocked even if the water runs clear when back flushing.

[GBMUD]

My Tdi used to behave the same. The rad was flushed, the fins were clear, no problem there. The 'stat was checked and was fine. When I eventually removed the radiator and looked carefully at it, the fins were all fine on the outside but peering in between them there were no fins at all left on the inside. I suggest you remove the radiator and inspect it under a good light so you can see "inside" the fins.

Chris

[Mark Jenkins]

Think we're heading for a new rad then. I'm going to put a bottle of "radflush" through it for this weekend but will bite the bullet in the week.

cheers

MJ

[Les Henson]

If you get a significant amount of carp out of the rad the first time, then I suggest you do it again until you have clear water coming out.

Les.

[Mark Jenkins]

Got a bit of carp out of it, perhaps not a lot. Ran it up M1 and same problem, rinsed with fresh - will do some more tomorrow but now must work...

[Turbocharger]

I'd suggest checking that the notorious LR temp gauge isn't letting you down. After a similar series of panic purchases to keep the Tdi cool, I bought a Racetech gauge (marked out in degrees C instead of 'cold, ok, worry') and that 'solved' the problem.

I had a multimeter and thermocouple (£16 from Maplins) gaffataped to the wing where I could see it, worked fine for ad-hoc measurements and good to 70mph .

[Mark Jenkins]

I'd suggest checking that the notorious LR temp gauge isn't letting you down.

In this particular case, it is definitely overheating, as there's other evidence besides the gauge (such as occasional steam, boiling noises)

cheers tho!

Mark