Thread: overheating 300 TDi

First things first - factory gauge is really a poor guide of engine temp.
Assuming the EM is well sensored and well wired lets use it for water temp.

86 deg celsius (the hottest your EM showed) is normal operating temperature.

Assuming all is well in a 300tdi it will heat up to thermostat temp (mid 80s) then lightly loaded in cool air run around 90 degrees indefinately.
Push it hard up hill with a load and say a poor condition thermofan it may rise to 105-110 and still be fine.
I heard the 15psi cap will vent at about 115 degrees but havent seen that myself. Theoretically 50% glycol 50% water at 15psi "boils" at 130degrees celsius, you may get pump cavitation before that point however?

I guess my ramble is - I cant see in your account where the 300tdi has overheated?

Steve

I'm with roverrescue, assuming your EM gauge is good, those numbers are within normal ranges so it's unlikely anything bad has happened.

After you stop the engine and there is no air flow or water circulation, the EM temp always goes up due to the heatsoak left in the engine bay.
You need to worry, when you start up again and it doesn't come down.

The normal temp gauge going up could be the due to a faulty sender or bad earth.

Squeaking sound is hard to diagnose with the info, but might only be a belt.

Ditto what the first two fella's have said.

Not sure on a Disco, but an OE Defender temp gauge is pretty much junk, and if the temp shot up at night I'd be looking at earth's as this is what happens in a Defender with a crook earth and headlights or wipers are used, displayed temp shoots up and frightens the heck out of you.

FWIW I've seen coolant temps of 104*C without issue in a Defender (although I don't recommend it, oil cooling becomes an issue too at those temps)

Rick my current record measured in top of thermo with EMS is 114 deg!!!!
Push hard up the byerstown with a shot thermo on a stinking hot day.
The current engine is going to the scrappers soon enough so Im happy to "play"
interestingly, no loss of fluid, no apparaent problems once up the range temp back down to just under 100.

I have been contemplating making a fixed fan hub just to experiment.

My current theory is from 100kph to $1.20 ram air flow over the radiator must be disturbed as my temp will just rise and rise, drop under 100kph and temps run back into low 90s. Very little difference in throttle position between say 95 and 105 but 10 degrees in water temperature.

S

yea i guess i have pushed the panic button a bit
but after reading the posts on this forum saying gloom and doom if the temp goes too high,
i just didn't want to go that high without more knowledge from this forum, i would rather err on the side of caution than have the expense and work involved in rebuilding the top end on a pension.
this morning put in a dribble of water, well 300ml anyway
it was basically the way the temp jumped up that worried me. previously the worst it got up too was 81 at a set of lights, it usually hangs around 77
yep i treat the OE temp gauge as a wonder gauge that's why i rely on the EM
i have just taken the water pump off as there was a bit of sideways movement on the pulley and i will replace the bearing on the adjuster pulley as well as that was freewheeling too well and a little noisy
thanks all for the support so far

forgot to add in the short time i have had the disco on the road it has impressed me and I'm very happy with it.
my last 4WD was a 1985 MK deluxe Nissan patrol turbo diesel. i loved it but the disco is a LOT more comfortable and as i said has impressed me in other ways

Originally Posted by roverrescue

[snip]

I have been contemplating making a fixed fan hub just to experiment.

My current theory is from 100kph to $1.20 ram air flow over the radiator must be disturbed as my temp will just rise and rise, drop under 100kph and temps run back into low 90s. Very little difference in throttle position between say 95 and 105 but 10 degrees in water temperature.

S

A few people have found this out, the fan clutch needs to be working well to pull air through the radiator at high speeds.
My theory is that the underbonnet air pressure is too high, not bleeding away fast enough, so the bonnet or 'guards need venting to help the air get away. (or a big front spoiler to create a low pressure zone under the car so the air can bleed away )

Unimformed has a mate who has a farm 'fender with a 200Tdi in it and both guards are vented (with the stock 200 and 300 air intake holes, the air cleaner has been re-routed) and he says that air blasting out of the passenger side one at 60km/h has to be felt to be believed.

Nissan Patrol's with the TD42T have the same issue, the crutch for it has been to overfill the viscous coupling to lock the clutch in earlier and it sort of helps.
Unfortunately SWMBO won't let me cut holes in her GU bonnet

Originally Posted by bigcarle

[snip]
it was basically the way the temp jumped up that worried me. previously the worst it got up too was 81 at a set of lights, it usually hangs around 77
yep i treat the OE temp gauge as a wonder gauge that's why i rely on the EM
i have just taken the water pump off as there was a bit of sideways movement on the pulley and i will replace the bearing on the adjuster pulley as well as that was freewheeling too well and a little noisy
thanks all for the support so far

FWIW the OE spec t/stat opens at 87*C (+- a few degrees) and a t/stat doesn't fully open for about another 8* or so.
I only use genuine ones, aftermarket ones aren't always specced properly.
I have a Tridon catalogue and have always used Tridon in other vehicles but their specced Tdi t/stat doesn't close the by-pass properly !
Admittedly that cat's a few years old and they may have noticed the error of their ways, but caveat emptor.

Originally Posted by bigcarle

forgot to add in the short time i have had the disco on the road it has impressed me and I'm very happy with it.
my last 4WD was a 1985 MK deluxe Nissan patrol turbo diesel. i loved it but the disco is a LOT more comfortable and as i said has impressed me in other ways

SWMBO went from an MK to a GQ then GU so I know where you are coming from.
The MK shorty was great in it's time but oh dear, it rode roughly, even with a few leaves missing from the front and back spring packs