Thread: 300tdi operating temperature

My 300TDI normally sits somewhere between 88 to 95c and I have only seen it go over 110c once and that was fully loaded with a 1200kg trailer going up a serious hill. The unit I have goes to 110c max but I would be pulling over if I seen it go above 110c. Since changing the viscous hub the highest temp I have seen has been 109c when towing up a big long hill.
I have one of these and the sensor is mounted up on the head near the thermostat housing. AutoSpeed - $25 Temperature Controller and Display!
Its a cheap option but works and I have connected a buzzer to alert me when the temp hits 105c.
Cheers
Mark

15psi cooling system pressure running 50:50 glycol will "boil" at about 130 degrees celsius.

Ive driven through 125 degrees celsius near the top of a rise in a sick tdi (no point stopping a hot engine when the downhill is just ahead - coasting nuetral with a few revs on the board will cool an engine far more quickly than stopping) but arguably as mentioned above once you are up to 110 degrees you have problems.

My only issue with a gauge/sender that has a max value of 110 would be top of range accuracy.
Often the upper ranges of a sensor are where its accuracy falls away. If the max value is 110 degrees, how accurate is it at 98 dgerees? (and does it matter )

Anyways, my ramble is saying go the 150, but its your coin and the 110 will most likely serve you well!

S

With my limited experience I offer the following opinion;

I have a digital temperature gauge, and low coolant alarm purchased from someone on this forum.

I will on average driving around Darwin with the A/C on see below 92DegC.

I will on average driving on the highway at less than 105km/h with A/C on see below 96DegC.

Now for the 'I DO';
I DO NOT drive my 300TDI Auto Discovery (with Defender tyres) towing my Camper Trailer (Tvan 1300kg, fuelled, water, and food) faster than permittable to keep my temperature under 98DegC.

And only once have I seen 106DegC (driving up 'the Hunchy' near mums place).

I like my engine to keep cool.
The longer it stays cool, the long it will last.
The longer the battery stays cool, the longer it will last.
The cooler the engine runs, the less pressure in the system, the longer the cooling system will last; I am sure you get the picture.

A few further consideration's: the hotter you run an engine the longer it will take to reclaim it's normal operating temperature. So if something goes horribly wrong you will see a greater temperature spike at higher temperatures (read exponential rise).
And, The hotter you run a diesel, the less fuel economy you will experience.

Cheers, Adam.

Never really gone outside of 80-100 normal op temp. Touched over 100 briefly, but that's it. As others have said, over 110 I would be worried and easing off. It would be sensible to say 110 is your max operating temp and buy the 110 gauge. If it hits 110 you would consider that red zone, thus shouldn't be driving anymore anyway.

It's perhaps being a LITTLE conservative, but others will say sensible.

80-100 also depending on the temperature and load. Id be backing off at 105 before it got any higher, I have my TM2 set at 104. The 110 would seem to be enough.

I have a Capillary type temp gauge fitted into the thermo housing on our Tdi, bought for $29 at Repco, only problem is it's major scale is in degrees F, must be a yankee thing but also has a degree C scale, normal running (with A/C ) shows just below 200F/93C but in mid wet heat up here fully loaded on the Mulligan at 110 going up Byerstown range she got up near to 240F/116C, and as any Disco owner should be aware the OEM gauge just sat in it's NORMALISED stunned state, so there is only one thing this gauge tells you, yes the engine is hot but by degree ......... not a chance. Just Ok to disaster in a step.
As "Roverescue" told me when I got my first old Tdi, "once that OEM gauge starts to move towards hot, the damage has been done". He has learned that through experience.
An aftermarket gauge is a good investment, along with the Enginesaver.
Oh, for you non industrial types OEM= Original equipment manufacturer.

thanks for your replies, exactly what I needed to know.

main reason for the gauge is to make sure any mods I do in the future don't increase the temp so having something to compare is the thing here, sounds like the 110 will do the job.

thanks again

Thanks for the link discomark the $25 gauge is now $20, so there are 2 of those going on order, for that price the wife's defender is getting one as well.

Thanks all again for the info