a couple of questions i may have already asked, can't remember...
have you checked your compression ? (thinking leaky head gasket or cracked head)
have you tried running with no thermostat ?

 

Last night I parked my truck on a level spot of land on my property and placed the front on ramps. I let the engine idle until the t-stat opened and I watched as air escaped. The coolant would rise and then *POP* a bubble would appear/dissipate. I would squeeze the upper hose and *POP* another bit of air would escape. I continued this for over 20 minutes as well as adding coolant when the level dramatically diminished. I also had the heater on full while I did this. After I was satisfied that all was well, with the temp gauge showing 195ยบ, I took the truck for a test drive. Wouldn't you know it, the damned thing kept going over the 205ยบ mark during the drive. I think it's time to pull the water pump.

 

Keep us posted. Man this is getting like a soap opra! I keep waiting for the next post that says," I FOUND IT". Good luck!
WC

 

Do i see a spark plug wire on the coil ? and why ? the conector is not even conected to the coil....

 

Try purging the system the fill with a slightly higher rpm than idle and recap it worked for me when i had no heat due to lack of antifreeze

 

No, you see a coil wire on the coil. I bought the stock 7mm from O'Reilly when I rebuilt the engine; however, I am looking for a recommendation for a brand of 8mm wires to put under the hood.

 

I figure I will add my story in here from this past weekend as it seems to relate exactly.

Trip to Springfield, OH for a huge International truck show from Harrisonburg, VA.

On the way up: ('98 Dodge 2500 360/Auto factory towing package pulling 16' equipment trailer hauling '67 Scout 800. Total gross weight: 13,400 LBS weighed upon leaving town.

I-64 on Sandstone Mountain pull (longest hardest pull of the trip, 7% grade for 5-6 miles) she begins to overheat, by the time we reach the top it is boiling over. Basically nurse it all the way up to Springfield at 50-52mph stopping to try a new rad. cap. We pull into the hotel at 7:30 (9.5 hours after starting)

Sat morning:
Put in new thermostat

Sunday: Leave out about 11:00 with a Wagonmaster (think '75 International version of the new Chevy Avalanche, only with D60s and an 800lbs 392 V8) loaded on the back (sold the scout) so now we are grossing an estimated 14,500 - 15K. Make it all the way into West VA on I-70, she starts over heating again. Pull into Cabella's parking lot, proceed to change water pump in the parking lot 3:00pm - 7:00pm Hit the road again. Make about 60 miles before we start hitting grades again and she over heats again. Find last autoparts store open on Sunday, get a new fan clutch, install after dark. Still over heats. Spend 2 hours trying to gor 4 miles up a grade to the next exit off the Penna Turnpike. Get off, get a motel room at about 11:30.

Monday: Call wrecker service from back home at 8:30 am, they arrive at 5:00pm, get towed home . $700 tow bill and I am home by 10:30 pm.

Tue: Call some shops and some dodge mechanics, they tell me it has to be a plugged radiator which was my next guess.

Now just waiting for Monday to go buy a new radiator at the local rad shop, cheapest in town, $209 for a brand spanking new one. I will let ya'll know how that goes. Before I install it though, I am gonna flush the entire system.

 

WesV
My symptoms are the same as yours,Irunnormal untill i load itwhile towing. Im going throught the same steps now. I ve changed several components and have flushed my system. After talking to the mech shops they all say thay our symptoms point directly to the radiator. I just dont know whether to pull it and get it roded or just buy a new one. I worry the plastic end caps will not resealvery goodleak later on down the road. I am very intrested in knowing your outcome, keep us informed.

 

Alright, here's the latest. In the mornings, when it's about 70ยบ or so, and I head off to work, the needle on the temp gauge crawls up to ~230ยบ once I'm underway. After a mile or two at that temperature, it them plummets to ~195ยบ and then hovers between 200ยบ and 210ยบ for the duration of the trip. I have not yet pulled the plugs to examine them, but I am *very* hestant to think there is a head gasket leak.

 

I'm sorry for going here again but, that sounds like a sticking T-stat. I know we've covered this ground before. Must be confounding the hell out of you. It is me, and its not even my truck!
WC