Over heating

[schimms15]

I have been reading the threads in here about overheating but here's my problem. My deuce was overheating and blew the head gasket, I redid the gaskets but it still was overheating, first I flushed the radiator which did not fix the problem a short drive on a 60 degree day would get the engine up to 200F, I did check the thermostat and it opens correctly. I then pulled the thermostat out completely and ran the truck and during a 15 min drive on a 70 degree day my engine hit 160F. This seems too hot, is the next step a water pump? Anywhere else that could be causing these problems? The radiator gets hot I did try to flush it out several times. I do have a new cap but did not put that on as the old one was holding pressure.

 

[gimpyrobb]

Sounds like its time to take the rad to a shop. It might need rodded, it might be junk. I've towed 5ton cargo trucks with mine and not overheated.

 

[montaillou]

160 is not too hot I don't think, in fact I read an old thread the other day where most people said theirs ran around this temp.

Mine runs around 160 when I'm driving around town. On the highway it'll be around 175. When climbing a mountain pass it got to around 190'ish, just below the 200 mark.

Do some searches and you'll see people saying all sorts of numbers in the 160-200 range. Maybe we're all running hot, but maybe not.

Also, according to this thing I found called: Military Specification, these are the performance requirements:

"Cooling system shall maintain a coolant temperature out of the
engine of not greater than 220°F with no evidence of aeration from the radiator under all
environmental and performance conditions specified herein and in the engine specification."

Page 17.

 

[gimpyrobb]

If memory serves, the thermostat opens about 180.

 

[davidb56]

mine runs at 125-130F. I checked/tested the thermostat too. I'll let you know how good the heater works this winter at -10F. can you run it with the cap off and see "flow" in the radiator? I would have doubts about the water pump going bad, as they usually just loose the seal and leak coolant everywhere.

 

[TGP (IL)]

My M35 will run at 160 all day long until you work it hard then it will reach 180,and then
The T-stat opens and the temp comes right down again.

With the manual engine fan and a oversized radiator these trucks run cool.

I would try a simple flow test of the radiator by holding my hand over the lower neck,
While filling with a hose.
Then when full, remove your hand and the radiator water should expel immediately with a "Whoosh" until empty.
Also if you leave the lower hose off, and fill with water it should run out as fast as your pouring it in.

If neither happens you need radiator work.
Tom

 

[schimms15]

The 160 is without a Tstat. With it I hit 200 and climb. I am gun shy to go much over 200 as I really don’t want to do another head gasket. I put a hose in the top and it runs out the bottom but does fill all the way back up to the top. The bottom flows well but might have some
Plugged tubes. I’ll push it without the T stat for a nice long drive I am very suprised it gets to 160 without a T stat as everyone I’ve talked to says it runs around there with a Tstat

 

[TGP (IL)]

"I put a hose in the top and it runs out the bottom but does fill all the way back up to the top. The bottom flows well but might have some
Plugged tubes."

"Might have some plugged tubes"?

That radiator needs to come off and sent to a shop.
It's plugged up!
Tom

 

[schimms15]

Alright looks like I’m pulling it in a few weeks when I get back to it and bringing it to a shop

 

[schimms15]

radiator is at the shop, the guy pointed out a few white lines on the outside and said it might need more repair, they think a full recore will cost 3K ouch. Hopefully It boils out fine and needs nothing else, I am in a time crunch to get it back in the truck Saturday so pick it up from the shop Friday. Hopefully they have it done by then.

 

[davidb56]

radiator is at the shop, the guy pointed out a few white lines on the outside and said it might need more repair, they think a full recore will cost 3K ouch. Hopefully It boils out fine and needs nothing else, I am in a time crunch to get it back in the truck Saturday so pick it up from the shop Friday. Hopefully they have it done by then.

there are other radiators that could be made to fit. You would no longer have a "original" radiator, but at 3K, I would find a good diesel truck radiator with comparable cooling capacity and size, and make it fit. things to keep in mind would be the coolant volume of the radiator, thickness (rows) and sq ft area, engine hp that it came out of, and ability to plumb that asinine lower hose placement to it. The original radiator has a large top tank, so a recovery bottle would likely be needed for a modern refit. I have a old F350 7.3 diesel radiator I keep as a spare that I would shoe into mine if I had to. BTW, on the lower hose area, to simplify the install, I considered using stainless steel fittings and tig weld them to make the needed bends, then have two short straight hoses on the lower.

 

[WillWagner]

Just an FYI, Don't run without a stat. These have a bypass and cooling loop. That's why there is a seal around the stat. Running without a stat will let the coolant take the path of least resistance, thru the block loop and not thru the radiator, resulting in an overheat condition. You should probably verify your gauge, military gauges are known for being....erroneous.

 

[frank8003]

"Running without a stat will let the coolant take the path of least resistance, thru the block loop and not thru the radiator, resulting in an overheat condition"
perfect

 

[dmetalmiki]

All my trucks, Both 2 1/2 and 5 ton run at 180 degree F. winter or summer..WITH the radiator cover on and only open at the top section.
M54 Camper shown.

 

[schimms15]

Thanks for the information. I will shove the Stat back in, just to verify which way does it go in? I think it goes back in with the shallow side facing the front of the rig and the deep side in the block well intake manifold. IS that correct?

 

[frank8003]

I found a piece of metal "something?" stuck in the spring and a wasted seal ring when looking for why it would never go over 160F°. Corrected that all and now runs at 180F° like it should.








TM 9-2320-361-24P Work Package WP 0036 00 figure 35

 

[frank8003]

OH, and the radiator overflow tube must be clear. With the radiator cap off one should be able to blow air thru that tube, they get plugged up.

 

[cattlerepairman]

3K for a recore...run and buy a brand new OEM radiator for a grand....3 HUNDRED for a full recore....acceptable.

 

[schimms15]

Thanks. I’ll be putting the T stat in tomorrow night and hopefully be all good

 

[gimpyrobb]

Yeah, $3k is Ludacris.