Overheated diesel engine in D69U

Check your precombustion chambers , they rust and let water into the cylinders .

Chronic leakers will have rust and pits vs black carbon on the head. Check carefully for cracks in the pc chamber-intake-exhaust triangle.

When you get it back together it may still overheat on a disk. You may want to just go ahead and rod out the flues of the radiator core before even trying to run it. I have a 9u we were using on a root rake, maybe babying it a little to keep from overheating. Soon as we put it on a disk, it was boiling!

Tried rad cleaner (quart of Muriatic acid) with no improvement, so bit the bullet and pulled the top tank off to clean the flues properly. Found a couple handsful rust flakes laying on the top of the core clogging the flues and about 80% of them plugged. We were able to get that down to 10% without resorting to drilling and blasting. It has stayed cool ever since.

[QUOTE=ccjersey;225317]Chronic leakers will have rust and pits vs black carbon on the head. Check carefully for cracks in the pc chamber-intake-exhaust triangle.

Thank you ccjersey, I did not suspect the inside of the rad. Now I know to check that.

Check the obvious first. They are notorious for having the fan belt slip.

Thank you sir, I will keep an eye on that too.

On a related note, I am planning to swap the damaged fixed blade fan (on removal, noticed that a couple of the blades had been bent and crudely straightened)
for an adjustable type off a parts machine we have here. Long shot, but as the fan blades were still a bit bent, maybe they were not moving air efficiently.

Always assuming the spare is in better condition of course

The first place a 318 engine loses coolant is pre combustion chambers ether rusted or the seal surface and washer are bad. Unless you know the history probably time to rod out the radiator.

Thank you Ray54. It is good to have knowledgeable folks suggesting similar things to watch for, very much appreciated.
Looking forward to getting back on it tomorrow.

Another pleasant surprise; Finning Caterpillar had a "valve grind" gasket and seal set in stock, picked it up today, also a valve spring compressor from the local dealer of made in China merchandise. The gasket set was quite pricey but to me it's amazing to find o.e.m. parts on the shelf for a 70 year old machine.

So to rod out the rad, it has to be removed from the machine?
I understand that the top of the rad can be unbolted, is the same for the bottom?
Or do you just rod and flush from the top?

Regards.

My D6 started overheating after discing for several hours, would run a little hot, then cool down on flat ground. The next day did the same only would not cool back down, was not in the red but was hotter than it had been running for several weeks. That evening when I shut it down, I saw the fan rotate a little after the engine stopped, what the? Went over and could rotate the fan by hand without moving the pully. tried tightening the belt a little, would not go enough to reach the correct position, time for a new belt! Installed new belt and it has run fine since. Glad it was the belt; though it is a bit to get it changed, took a while to let the loose juice do its job so the adjusters could be moved enough to get the old one off and the new one on. Good luck with yours. Tom