Why don't diesels make heat at idle?

[SmokinU]

My truck is the quietest when I let off the go pedal as well, as when coasting down a hill, even quieter than at idle. Another dumb question, what is that cylinder washdown that you all talk about, and what is bad about it?



Brandon

 

[rbattelle]

Originally posted by SmokinU

My truck is the quietest when I let off the go pedal as well, as when coasting down a hill, even quieter than at idle. Another dumb question, what is that cylinder washdown that you all talk about, and what is bad about it?

Washdown is when unburned fuel is literally "washing" the cylinder walls. It tends to remove the beneficial layer of lubrication normally present. At least, that's the way I've read it defined somewhere in here.

 

[AWM]

I have noticed IDI( ei:GMs 6. 5, my ford tractor), diesels will warm up idling, meaning they are less efficeint, more heat is rejected to the cooling system. Bob