Yesterday i noticed some coolant loss which is now being looked into at the shop.

this got me thinking about what to do should the engine overheat for whatever reason. I've been told that just pulling over and letting it idle will allow the engine to cool down and that the worst thing you can do with any overheated diesel ( ie warped heads, etc) is shut it down right away. Can't seem ti find any confirmation on the net. Is this correct advice or not?

thanks in advance for your input.
John

Interesting question. I don't know the answer though! I would guess shutting down is best, since a running engine produces heat.

Don't shut it down right away. This stops the fan turning, and keeps the waterpump from circulating the coolant away from the block and through the rad. If you're on hand of overheating, I'd pull over, idle (maybe even set the hand throttle up to 1200 or so to let the alternator keep up) and turn the heater fan all the way to high, on the highest temp. This will bleed off some of the heat from the engine, into the cabin. Oh, and if its a nice day, get out... <img src="/forums/images/graemlins/scared.gif" alt="" />

I once drove from Nfld to Calgary in Betsy II (3.0V6) towing a trailer. Temp gauge was starting to climb, so I pulled over when I got through the worst of Montreal traffic, at a rest stop, and was just breathing a sigh of relief after I shut her down, when I saw steam coming from under the hood. Shoulda left it running... <img src="/forums/images/graemlins/baby.gif" alt="" /> After she cooled down all the way and I topped off the water, I did make it the rest of the way west, but I could've avoided the overheat if I'd let her idle for a few minutes. Lesson learned.

But, what if there is no coolant left to circulate? Idling would let the fan blow, but maybe stopping and opening the hood would be better in this case.

I guess it depends on if you know what has happened under the hood.

I drove a vehicle once that had less than 1/2 its coolant. The gauge read full cold until I hit a bump and sloshed some around then the sensor would jump. Luckily it was -20C out!