3406 high coolant temps

Retarder. Sometimes they can drag just a slight bit and heat up the oil, which would translate to higher coolant temps. Just spitballing ideas because this is a strange issue.

 

Honestly I think you have looked at or done everything. I got one more thought. On the new core that was put in, are the fins attached to it right? Or are they loose feeling? It's hard for my simple vocabulary to describe but if the fins are not right or there isn't enough of em she won't dissipate the heat

 

It's just that there's really nothing else to look at after hearing what you've done to this point. Right before our eyes you had the oil cooler apart and cleaned, and it didn't look like it could have been causing that much of a problem truthfully. But it eliminates another point to look at at least.

If you've replaced the thermostat (and I've had a couple of them out of the box be defective too, BTW,) water pump, all the other little things you've done...other than performing a flow test to determine if the water pump impeller is spinning properly...you have no compression in the coolant system indicating a head gasket/cracked head, not losing a drop of coolant...then the only thing left to blame at this point is a faulty, under-performing radiator. Water pump and radiator...what else is there to look at?

I feel your pain, believe me...it's awful chasing invisible problems. I have been chasing a torsional vibration in my A Model now for over 15 months. I've done everything from swapping tires off my other A Model that drives like a car, to all brand new suspension, bushings, alignment, shocks...and I have a worse gallop now than before I put new shocks on 3 weeks ago. I don't want to just throw money at it pulling driveshafts out and sending them to have balanced, or buy all new brake drums, so next Friday I'm going to my local truck shop and we're going to run it up to speed sitting on jack stands and physically look at everything to determine what is the cause. It's not the least bit enjoyable to drive at the present time like this. Feels like the cab's coming off at 65 mph. Throw it in neutral, speed up, down...still does it. Driveshafts are all tight, all U joints new...carrier bearing new 2 months back, brand new drive tires 2 months back...what the heck can it be I keep asking myself. Friday the 13th we'll find out. I'm leaning towards brake drums out of balance myself, but again, I'm done guessing until I physically see what's going on for myself.

 

@rank . We had an air line one time that looked great off the truck but was split inside. Put pressure to it and it would bulge in blocking the flow.

 

Air in the fuel can make one act just like retarded timing. Slow to rev but pull good elevated pyro temps etc. Look at the bubbles in the tank if the top of the fuel is covered with them you might have an issue. That said i can't see that or the timing being it.

 

Timing can be an issue for it surely, retarded especially. It'd be a good idea to find someone around that can pull the cover and check it just for peace of mind. I have mine advanced a bit, a bigger turbo, and I have a pretty substantial oil leak behind the injection pump where it bolts to the block that I have to address sooner than later. But I have to bring it back to the guy that I had set it when I had the motor on the car trailer a month ago for him to do rods and mains and put the Jake on. he's got his own formula for everything, and knows just where and what he set it at, so I have to go back to him just for the leak unfortunately. The upside to it is, it runs respectably with his recipe.

 

This is clean in the picture. When I bought the truck I'm driving it had a seized engine, seized on the crank. Radiator, oil pan, all was full of red silicone chunks, every piece bolted on the engine has mass amounts of red silicone hanging on it!! Checking your radiator could be a good thing?