Exhaust temp gauge Nissan 3 ltr TD

Hello MotherHen,
Don't have an answer for you but with your indulgence I'll borrow some air time in your thread.
Who'd you talk to about transmission and exhaust gas temperature monitoring?

Geoff.

Hi Motherhen,

The safe limits for Exhaust Gas Temperature (EGT) depend on whether the temperature sensor is installed before or after the turbo-charger.

If before (i.e. between the exhaust ports and the turbo), temps up to about 720 C should be OK for brief periods but I don't like to see more than 700 C for more than a few tens of seconds.

If the sensor is downstream of the turbo (e.g. on the exhaust pipe just below the turbo outlet flange), the maximum safe temp is quite a bit lower. As the exhaust gases expand through the exhaust turbine, they give up energy (to drive the compressor side) and emerge at a lower pressure and temperature. Unfortunately this temperature drop will vary from one engine design to another, so it's difficult to put an exact figure on it. Some sources quote figures of up to 200 C and I have actually measured temp drops of over 160 C on my Land Rover. So, the maximum you probably want to see downstream of the turbo is probably about 500 to 550 C.

I always recommend an upstream installation if at all possible, as it is the hotter upstream gases that are impinging on the turbine blade tips, the turbine housing and the wastegate valve & seat. These are the bits that usually suffer first from excessive EGT but in extreme cases, the piston crowns and exhaust valves can fail too - very expensive!

Please feel free to visit my site and download the EGT Information Sheet. It gives (I hope) a good description of the causes and effects of excessive EGT. Hope this helps.

Motherhen,
I have fitted an EGT on my 3l auto Patrol and the temps I am seeing are
Highway cruising @100k,s 400- 470
Highway cruising @ 110 k up to 520-535.
Town driving 350 - 380.
Naturally the terrain has a lot to do with temps as does headwind etc.

The highest I have recorded has been 565 pulling our van up a steep range, but this soon came down to the low 500s by easing off the power.
By the way I am reading the temps just down stream of the turbo.
Would be interested in your readings as a comparison.
Hope this helps
Graeme.

Motherhen, all the auto's come with a light warning about transmissions running too hot, the problem is that often by the time the light comes on the auto trans is so hot that damage has already been done. As an example. About 3 years ago our auto light came on climbing the hills on the Princes Hwy down past Orbost on our way to Merimbula. We stopped, let the auto cool down and topped up the trans just slightly. The light never came back on and we drove around Merimbula happily for a week and on our return to Melb the auto trans destroyed itself totally in Traralgon, no warning light, no nothing, resulting in a $4000+ auto trans rebuild.
What apparently happens is the factory lining can come apart from the torque convertor lock up band which then clogs up the oil cooler mounted in the radiator and the auto then cooks itself as the oil has nowhere to go.
If I had a proper gauge I could have monitored the normal auto trans temps, seen an increase in temps and had it fixed while on holiday and saved myself a lot of money in repairs. It still probably would have required a rebuild but at least I would have saved the planetary gear set which was totally destroyed in the blow up.
I now have a VDO gauge on the trans and can accurately monitor auto temps, particularly when under load towing or 4 wheel driving.
I also have a manual lock up switch for the torque convertor so I can tow in 3rd gear and lock up the torque convertor at any speed. Locking up the torque convertor is the key to running your auto trans at the lowest temps possible.
Regards Andrew.