Hey guys, I had my reliable D2 overheat on me a couple months ago for the first time and have since gradually replaced the radiator, 190 thermostat, expansion tank, expansion tank cap, viscous fan/clutch, head gasket and valve job completed last week. After all that it still overheats.
I pulled the water pump and it looked perfect but I ordered a new one anyway as well as a motorad 180 thermostat and a new coolant temp sensor, these go in tomorrow. I don't see how they are going to change much but I figured I should complete my process of elimination, I should also mention that the cooling system has no leaks at all and holds pressure well, system has been flushed and back flushed several times including heater core, also hydrocarbon test came out all clear so no exhaust gases in coolant....
I'm beginning to think I'm just not bleeding the damn thing properly! I fill from bleed screw then elevate expansion tank and top off until coolant flows from bleed screw before running and allowing air to bleed out of tank.
HELP!???

Thanks, Josh R

 

motorad 180 thermostat are junk,it could be your whole problem, I would get a dark gray LR TD5 T-stat.
i poured boiling water from a tea pot into one and it never opened. jmho

 

not clear on your bleeding procedure.

the procedure I've been using, as suggested by others here is as follows:
remove expansion cap
loosen or remove bleed screw
raise expansion tank until coolant runs out of bleed hole, tighten or replace bleed screw, lower expansion tank
repeat 2-3 times
replace bleed screw, elevate expansion tank
start truck with heater on hi (may or may not help, much debate about this)
let truck run up to operating temp, replace expansion cap
re-seat expansion tank

x2 on the TD5/warm climate/180 LR t-stat

 

OK thanks a ton guys, o putba brand new 190 thermostat in it and then figured that was the issue so I bought the 180 motorad, I haven't tried starting it with that in yet, will do this afternoon. I will follow your bleed instructions carefully and see what happens, if I still have issues and the obd gets above 210 I'll invest in a TD5 180 stat.
JR

 

LOL I see these threads and I chuckle.

I went through EVERYTHING you just described in your thread OP. I mean everything. I changed out everything, every component, every hose, 180 Tstat, new coolant reservoir, new hoses, new clamps. You name it I replaced it. No leaks, held pressure at 15psi. Truck would idle at temp all day, as soon as you drove it it would spike then over heat. I went through 12 gallons of coolant on my journey. Turned out to be s slipped liner and I got a new rebuilt engine.

If your cooling system has no leaks, holds pressure, you bleed it until your fingers bleed and it over heats when driven (not at idle) it is more than likely a slipped liner sleeve.


Good luck and I hope it's something simple.

 

edit: didn't see that part

 

Well it's not just a slipped liner which would cause the overheating issue you describe but a crack in the block behind the sleeve. The sleeve itself has nothing to do with sealing the combustion chamber from the cooling system, slipped or not. The op has stated there has been a test which, if accurate, has revealed no combustion gases in the coolant which indicates there is no passage between the combustion chamber and cooling system so it should be another issue.

 

Appreciate the input guys, I really hope its not a liner/cracked block issue, I have faith in the hydro carbon test though. We shall see, I couldn't get the damn water pump gasket off today so I will try again tomorrow with less beer in me and a can of some kind of gasket softener/remover

 

make sure you have the thermostat aroud the right way. I recently bought a DII and had similar overheating. Did the full flush, changed everything. I took picture when i took everything off and put it all back the same way.

Engine would run ok, but just temp would go up on idle - fine when running at highway speed.

Anyway, looked up the flow again in the rave manual i had and made sure i had the thermostat in the correct way according to the rave manual and i did.

But then i viewed a video on youtube and the angled section of the thermostat was going toward the pump. I had the angled section going towards the top hose.

I spun the thermostat around, refilled, and wow - everything worked. No overheating, and only a very small variation in temp between idle and driving.

See this pic - its directly from my rave CD - and its wrong. The angled piece goes to the pump, not the top hose like this diagram.

 

I didn't mean to suggest it was.

But if you have no leaks, system holds pressure and is bleed properly then the truck should run with out over heating. It's not a overly complicated cooling system.

My point was merely that you can only cross so many T's or dot so many I's before you have to start looking at other reasons for your engine to over heat.