Help, I am Overheating

[BHARD]

When my truck is not towing the temp guage might as well be painted on, it NEVER moves once truck is warm. However, if I am towing it heats up anytime the truck is pulling up hill, often over heating if the grade is big enough. Outside air temp seems to be a factor, I live in San Diego and travel to desert often. I have changed thermostat more than once, and settled on one that works better than the others, but still i hve the problem. I am told that heat is actually coming from the transmission, and that the engine and trans cooling systems are somehow linked. Anybody have any ideas? Feed back would be very welcome.



Bill

 

[Joe G.]

Bill,



Have you checked to see if the fan viscous clutch is working?



I really doubt that the transmission cooling has any affect. There is a small transmission cooler under the exhaust manifold where transmission fluid is cooled by engine coolant, but only a small portion of the total coolant is involved.

 

[illflem]

I agree with Joe on the fan clutch. The easy way to check it is to just listen when the coolant temp climbs over 200°, if you don't hear one hell of a lot of noise and a power drop, it probably isn't engaging. The fan pulls 22 HP when fully engaged and really roars!!! It spins all the time but isn't locked up till the temp climbs. Only other thing would be clogged cooler fins, but I'm sure you thought of that.

 

[Randy]

BHARD,

I had the same problem, I was told to replace the thermostat. Sometimes they stick and don't open all the way. No problem when not towing, but with the load the restriction becomes evident. After I replaced mine, even towing my 26' 5er up 10% grades in the middle of summer my temp gauge never gets past 190. Randy.

 

[MGire]

With an automatic transmission, if you are working it really hard, especialy in the lower gears out of lockup it will get really hot. Up to the 250-300 degree range. Measured in the output line from the torque converter. This fluid goes into a heat exchanger in the engine before it gets to the aux cooler in front of the radiator. The heat exchanger is to aid in transmission warnup when its cold. When it's hot out pulling a grade with a load on the transmission is dumping a lot of heat back into the engine and the cooling system can't keep up. Get gauges and talk to Bill Kondolay at Diesel Transmission technolgy.

Mike

 

[scott4glamis]

try using an after market trans cooler with a fan, try one with a rating of @19000 lbs or greater. where do you get your high temps (i-15 n , hwy 76(pala reservation)or ?). try getting a trans temp guage, and mount the sensor in the trans pan. (pep boys<@50. 00), you will need a bung welded in to the pan . also a " big honkin' air filter " might help reduce egt's@ 50 degree's thereby reducing the under hood temps, if you are towing heavy

a pyrometer, boost guage and trans temp guage are "essential. "

p. s a member i know plumbed in a mister system (like for your porch) into the washer bottle circuit to spray on the radiator for those long pulls, he pulls a5er with up to 4 cars on it,commercially, '99 with 220000 on it.

 

[WestTN]

overheating

If you try an aftermarket cooler, make sure you use one made for the Dodge. Watch the tube diameter. Restricting the flow will only kill the transmission quicker.

Good luck

 

[TowPro]

Change the thermostat. If you want to prove its the problem, put both the new one and the old one is a pot of water on the stove, turn on the heat, watch them open. I bet the old one only opens 1/2 way, been there, done that in 1998!



While you got the thermo out, remove the lower hose and flush the block and radiator, then refill with new coolent.



Try to catch all the old antifreeze and recycle it, its about the most toxic stuff in your truck I hear.

Originally posted by BHARD

When my truck is not towing the temp guage might as well be painted on, it NEVER moves once truck is warm. However, if I am towing it heats up anytime the truck is pulling up hill, often over heating if the grade is big enough. Outside air temp seems to be a factor, I live in San Diego and travel to desert often. I have changed thermostat more than once, and settled on one that works better than the others, but still i hve the problem. I am told that heat is actually coming from the transmission, and that the engine and trans cooling systems are somehow linked. Anybody have any ideas? Feed back would be very welcome.



Bill

 

[RedRamer]

You say when you're not pulling the temp gauge might as well be painted on.

The Cummins is known for a fast moving temp gauge when not pulling. It should drop fast from your high mark to low mark, then crawl back up again. If not, then I'd make sure you got the right thermostat.

 

[rkressg]

Empty, my temp gage stays just below 190 and never moves. When I tow anything over about one ton, my engine runs at about 230 degrees and the clutch fan does not kick in until the gage almost maxes out at 240 degrees. It doesnot matter how hot it is outside eather.

 

[RedRamer]

You might want to check the temp sending unit also. Sounds like it's deffective. Empty or pullin, I never see 90 = about 194 US diggers.

 

[Steve M]

It's the thermostat. The fan clutch isn't kicking in until such a high temp because the hot coolant isn't reaching the radiator because the thermostat isn't opening. It's being held in the motor. The soft seat thermostat lets enough through that it finally causes the fan to react but it's still not flowing the coolant through the radiator enough to cool the motor. The soft seat thermostat was implemented to stop the swinging temp gauge after some customers whined about it. No more swinging gauges but the soft seat thermostat doesn't work as reliably as the older thermostats. I'd rather have the old style thermostat back with the swinging gauge.