Years ago we had a car that spasmodically overheated, we couldn't find anything wrong at all and even changed the head gasket. (clutching at straws) It would run fine for mile after mile, then out of the blue it would boil up and dump water out of the radiator fill cap. Just out of curiosity I pulled the water pump and found the problem, the impeller, an interference fit on the shaft, was no longer tight and could be turned on the shaft by hand - a new pump was fitted and the problem vanished.

I'm not familiar with CAT water pumps......

Julian.

Just some thoughts

Ambient capability can be effected but heat radiation off engine and components, i.e. engine block, turbo charger and exhaust manifold (muffler) etc especially with a blower fan on the radiator. Cat have indicated up to 3 deg C +.

Radiator performance diff "T" can indicate efficient operation but if the problem was related to temperature regulator and or excessive bypass via bypass gallery to pump inlet, which can be check i.e. water pump inlet & water pump outlet.

It wouldn't be the first time a impeller came loose on a CAT 3306 or 3406 etc, sometimes you can pick it by leaking seal or a burnt spot on the front cover of pump.

I very much enjoy everybodies trouble shooting.

Thanks Robby,
Lost track of which was which....

Has that heating been consistent or intermittent?

...one more thing I did was to take the engine side enclosures off my D6. I suspected that it might not be getting enough air flow. They clog easily with trash if your're running in a field with a lot of dry leaf litter/grass.

Hello,
The engine heats up only when under stress.
It seems to me that compared to the D5, master for me, (in any condition where stress is not the tool spends half of the green zone), the D6 blows less air from the fan, so I was advised to reduce (diameter -25 mm, a little in my opinion) the diameter of the fan pulley (so it runs faster and more air). so did I, and with respect to last year something has improved. Again, if the engine tries, from 2000 rpm to 1700-1800 rpm the instrument remains in the middle of the green, otherwise it comes near to red, but always in the green zone. The situation is not very serious, every day i work. I'm not quiet, all the time I look at the instrument, i'm quiet when drive the D5, I forget the instrument.
Robby

Hi Robbie,
Your D6D will run hot, the fuel pump has been adjusted to give more horsepower = more heat = more than the radiator was designed for, although it seems to be working within specification. if you work our how much extra work you do in 3rd gear compared with the extra fuel you burn, you may find it better to keep in 2nd gear and give the engine an easier time.
The best thing to do is to fit a high temperature warning alarm then sit back and listen to the radio and wait for the alarm to sound rather than watch the gauge all day.

Hi Catsilver , I will follow your advice, maybe I'm worrying too much.
Thanks for the reply. Bye