I have a overheating problem and I had the radiator flushed and put a 180o thrmostat in and still overheats when I pull my fiver 8500#. Would bumping the timming up 1-16th do any good ? If so I need to know how to do it.

Thank you,

charliex25

 

What do you drive? auto or stick, intercooled? using your A/C?

 

Yes I have an auto tranny 1991 554 340k runs great but over heats on a long up grade pull.

charliex25

 

What kind of indication do you get? It is not unusal for the factory temp gauge to lean heavily towards the high end of the "normal running zone" in the gauge face while pulling heavy at high outside temps. It is unwise to run any higher than the last 1/8 inch in this area. Does your truck have an air to oil transmission cooler behind the grill? The stock torque converter is sloppy at best and generates a significant heat load on the cooling system. Auxiliary oil coolers help and so does changing out the torque converter to something more efficient with a lower stall rpm. Some of these trucks came from the dealer with an additional cooler and fan mounted under the truck near the tranny.

 

Sounds like maybe a bad fan clutch to me?

 

I am pulling about 10K and I've got the same problem since I turned up the fuel screw,the heat from the extra fuel burned does run the engine temp. way up.Even running on the flats I can't pull in OD.because it will run the temp. right past 220* if I don't watch it. EGT runs 11-1200* on a hill so I do hills in second gear.I've even thought of plumbing the heater hoses to a 5 gal. can of coolant in the bed.to see if that will help.I wonder if 2nd and 3rd gen. trucks have the same problem.

 

Someone correct me if I'm wrong, but doesn't bumping the timing make the engine run hotter?

 

I am definitely no expert; but, I once had an automatic truck that would over-heat on grades when towing.

The transmission cooler was actually plumbed into the radiator.

I mounted a big after-market cooler and dis-connected the factory cooler.

Problem cured and the truck never offered to get hot again.

 

Do you guys who have the overheating problem happen to have tranny temp gauges by any chance? My tranny always seems to run cooler than my motor and the probe is in the stock location, which should be reading the peak ATF temps. I thought I read somewhere that if you disconnect that heat exchanger the tranny overheats very easily?

 

that is what I have heard also, they will over heat without the water/oil heat exchanger.

 

Yes this is tru the more you advance the timing the longer the flame(and added pressure(heat) is in the syl and not the ex.
if you retard the time the heat starts to show on the pyro!

I have both problem so i have just left it at 1/8 bump untill i can get a intercooler or a bigger radiator!

EDIT: A...that would be 1/16 as my sign below showes

 

I put the cooler on the return line to the transmission after the heat exchanger,I probably should have put it on the hot side to take some of the heat out before it gets to the exchanger so the radiator doesn't get it.
I had the guage first before I got the cooler and running empty the trans.temp would be close to the engine temp. but pulling the trailer it would peg the guage at 250* on any hill.With the cooler it rarely gets over 220*Since I turned the fuel screw the engine temp goes to 220* or more on most hills.With the single car trailer its not an issue but with the GN I really have to watch it.

 

Ive logged over a million miles towing up to 26K with my 93 and what I was faced with was every 250K I had to rod out the radiator. The OEM radiator uses very thin tubes and the silicone in the antifreeze would plug the bottom 1/3 of the radiator. A very easy way to check this is to run the truck just enough for the thermostat to cycle once then run your hand down the radiator top to bottom as close to the middle as possible. you can pull the fan off which makes it really easy. If its plugged, the top will be hot and the bottom noticable cooler. Powerflushing didnt do anything to clean it out, it HAS to have the end tank pulled off and rodded. Also dump in some water wetter and switch to fleetguard coolant its a low silicate diesel coolant.

 

Might want to consider picking up one of those infra red temp guages, then you can check temps at upper and lower radiator hoses and over the radiator to look for cool spots which would indicate a plugged area. It would also let you know if your guage is reading right. If you can't hear your fan engage you probably have a bad fan clutch, mine comes on when the temp guage reads just above 1/4 and soounds like an airplane going overhead.

 

Right but remember the oil cooler/exchanger uses the coldest water from the return side of the radiator to cool the trans fluid so your gauges might read 180 water(hot side) and 160 trans fluid, but the trans fluid is cooled with water that is probably closer to 130 at the return side so you are still adding a bunch of heat to your water.