Thread: 300Tdi - water temp questions

129 deg cel it appears if you are using a 15psi cap and a 50/50 ethel glycol mix.

with a mechanical VDO gauge mine used to run at 90-92*, 93-95* going up any hill, summer or winter. You could see the t/stat start to open at 88-90* any morning after about 5km at 60km/h.

After re-fiiting the air con condenser, the temps immediately went up on hills to 96*, 100* in warmer weather and a long hill.
Tried a new viscous fan hub and the same temps.

The fuel pump is wound up pretty well on this thing, too, but the difference in temps after fitting the condenser was immediate.

I too have a mechanical fitted and it sits around the 90 mark when cruising at 100 and goes up a couple of degrees on a good hill

Hi,

I have a second thermocouple for coolant hooked up to my EGT gauge and can switch between the two. The coolant one is into the side of the thermostat housing. As mentioned by others, the thermostat opens in the high 80s. Cruising can be anywhere up to the high 90s solo and somewhat higher when towing 2.2T. Varies greatly with ambient temp, especially when towing.

Best (?) ever was 114 C, towing the 'van in 45-46 ambients in NT/northern WA with air con flat-out and no a/c condenser fans (they'd died some time before - and still not replaced, now you mention it). Eased-off a bit after that to keep it under 110. As I recall, EGT was in the high 500s/low 600s too, so we must have been butting into a fair old headwind. Engine is well fuelled-up too. Conclusion: 300Tdi cooling systems are fantastic, as long as you keep them full of clean coolant (P-gaskets and split reservoirs are another matter, though.)

Originally Posted by Leo109

Hi,

I have a second thermocouple for coolant hooked up to my EGT gauge and can switch between the two. The coolant one is into the side of the thermostat housing. <snip>

Good Idea.
I fractured a capillary on my gauge 4-5 months ago and was thinking about doing exactly this.

Hi Rick,

The wiring needs to be done with some care to avoid introducing measurement errors. Send me an email if you'd like full details. Also have a couple of 6mm x 50mm insertion length straight thermocouples lying about too...

related to water temps. Ive noticed that on my '95 disco 300tdi engine, the 90 degree alloy bend from the thermostat housing to radiator hose has two threaded fittings, each with electrical fittings. The wiring harness is connected to these. However on the '95 fender 300tdi the two fittings are blanked off in the casting.

These are not as far as i can tell thermocouples for the main engine temperature gauge as it is on the head.

What are these for? what circuit do they tie into? I looked through the electrical diagram for the 300tdi disco and couldnt track either "sensor"

regards
Steve

Hi Steve,

The coolant gauge sender (X114) screws into the head, just below the thermostat housing, as you've seen. The two switches that screw up under the coolant outlet pipe on your Disco are: (closest to the head) X113 Condenser Fan Coolant Temperature Switch and (closest to the radiator) X259 Compressor Clutch Cut-out Switch. Methinks your Disco has air-con but the 'fender doesn't?