D69U Question

.0012" or .012"?? There's a world of difference in an extra zero. Regardless, even at a 12 thou shave, you shouldn't need to trim the dowels. Crank her up, she'll run.

.012 is what I meant. 12 thou is what I took off. I will continue putting it back together. When the D6 overheated, I wasn't around. I wasn't around during the couple of months of use that led up to the overheating. I had three bad injectors, the seals around the ferrels didn't look bad but I replaced them all. Is there anyway to check the water pump? I spun it and it turns smooth. My Dad (that's who overheated it) said that when he looked in the radiator while the cat was running the water wasn't circulating. Should it have been?
Thanks

You can easily check the thermostats or "regulators" as CAT terms them. That would be my bet. I have done it by only removing the top section of the thermostat housing to expose them and refill the system just to the level of the flange there. I heated the housing with a torch until I got them to open up etc. It can be a pain to get them out of the housing, because of the retainers that hold them in, but you can rig up a puller with some bolts and scrap iron etc.

While the hood is already off, you can pretty easily remove the fan and pull the front out of the water pump housing and have all the important bits right there to look at. There's really not much that normally goes wrong with one though.

The hard part of the water pump is bolting the housing back to the block, head and the water elbow after you put the head back on! I try to leave the lower bolts to the block in place, only loosen them enough to allow for clearance to reinstall the head and get the upper gasket in place. If the gasket doesn't crack you are good to go!

Where is the thermostat located? I already removed the bottom two bolts that hold the housing when I took the head off. I hope there not too hard to get back in.
Thanks

They are in that rectangle shaped box on the right side of the engine and there is a hose that goes up to the top of the radiator.Also the manifold part of it has the 6 water connections that go to each cylinder on the head.There are retainers on most except possibly the latest 9U tractors that hold the thermostats in so there is a special puller for them but guys on here has rigged up one themselves so maybe someone on here will come back as how to rig up one.I don,t have a parts book to check what SNs might not have the retainer to hold the therostats in but would probably be the latest tractors made.

If the water pump spins smoothly, the bearings are O.K. If the seal holds coolant, it will be O.K. to leave the pump alone. The only time you need to repair the water pump is when a bearing starts to collapse, or the seal leaks coolant, or both.

IIRC, the coolant movement can't be seen properly by looking into the radiator top tank .. because there's a cast plate that holds the bolt, that the radiator cap screws onto .. and there's only a small hole in that plate, to let you see the coolant.

It's very important to check the regulator, and ensure it's working properly, it plays a crucial part in the engine cooling system.
That is why Cat call it a "regulator" - it regulates the temperature, not only by opening and closing, when the engine is hot or cold .. but by providing the correct amount of restriction in the coolant flow. If you remove the regulator, you're increasing the coolant flow rate, and under the right circumstances, this will lead to overheating.

??????
There is no water distribution manifold on the D318.
There are two thermostat/regulators.
The Permatex Super 300 is the preferred cylinder head gasket cement. Light coating, complete surface, both sides.

When it overheated a big puff of steam came out on the driver's side of the motor. I was told it was coming out near the front. Is there some type of pressure release valve?
Thanks

Yes, there's a pressure relief valve mounted on the top of the top radiator tank, right between the radiator cap and the top water hose connection.
When the system become overpressurised by the engine boiling, it releases a stream of hot water or steam.