radiator and heating question

[opel]

I found one post close to the problem I am having but thought I would post for more suggestions. I have a 91 auto trans 4x4 and is also heating up on grades that are not that long. Pulling about 8000 pounds and by the top, if I stick it to the floor, it is getting to the last line on the temp gauge but cools quickly after I top the grade. Pyrometer says about 900, transmission gauge says 200-220, and on the floor the boost says 20 psi. I know the trany will help the engine heat but it has an extra cooler in front of the radiator, and according to the trans place is normal temp, just not to go past 260. I had a 5 speed before and I could'nt make it heat! The radiator is a cross flow, but aftermarket. It says Radiator Performance and has a picture of a cactus by the cap. Its is a 3 core like oem, but I am thinking it is getting plugged or not a quality radiator. I have never had trouble with oem radiators. I replaced the water pump, thermostat, belt, has good shroud, fan clutch comes on normal at about 3rd line on temp gauge, checked the cap, and washed the outside of the cooler and radiator. Even when I lock out overdrive and rev her up in drive where it is easily pulling the trailer it still climbs but slower. I have good power, BUT I CANT USE IT !!!!!! The engine is very sound and has been freshed up about a year ago but didnt change the promplem. Acts like a flow issue. What do ya think.

P. S. Great site, old owner but new member!

Thanks.

 

[Paychk]

I seem to remember one of the members posting that he found a large amount of crap between the radiator and the CAC (inter-cooler). Have you removed them from the truck and cleaned both thoroughly? Also what brand is your thermostat? there have been a lot of problems reported with any but Cummins t-stats.

 

[JStoll]

check this out

get it warm on a grade or what ever when its hot pull over & shut it off imediatly get out & feel the core of the radiator quickly if there are cold & hot spots its the radiator you will almost be able to feel that certain core tubes are cold while the one next to it is hot

the reason you do this quickly is because conductance & convection will give you a flase sence of whats happening

the other scenerio is that the thermostat may not be opening fully you can tell this if the radiator core temp is fairly even mabey slightly cooler where the fan blades pull air through but not black & white like erlyer mentioned

thermostats operate with expanding wax in the brass part under the spring this pushes out the pin on the side away from the spring overcoming the spring & opening when an engine gets hot the wax can get too thin & leak out a lil causing the Tstat not to open fully Ive opened the caps on cars seen a few dots of wax in the coolant & known rite off that the Tstat was bad

you might just change it & see if it gets better as well its cheap & cant hurt

take care

JAK

 

[opel]

The thermostat was from Dodge. Maybe I'll try a Cummins. When I changed from the first one it did'nt seem to make much difference. Its clean between the two ( radiator and intercooler. ) Hopefully another t-stat will cure it. Thanks

 

[Midnite]

Opel, are you taking those grades full-throttle in overdrive? If so, that's what's doing it--that'll heat up your transmission fluid like crazy, and kill it in short order too.



If you're towing with a stock automatic you want to take the grades in 3rd gear, not 4th. The engine will turn at a higher rpm, but you'll immediately notice cooler temps (both transmission and coolant). Overdrive is usually perfectly fine for the flats.



The reason you couldn't make the 5 speed manual transmission fluid heat like your automatic is because the 5 speed didn't have a torque converter which is designed to slip a certain percentage. That percentage slip increases when you increase things like engine loading, and performance mods--since you've done both, you're exceeding the capabilities of your torque converter to efficiently transmit power to the wheels. When you read about "tighter" aftermarket torque converters, this is the problem those torque converters are addressing.



Mike

 

[rlyons]

I see you have a winch on your truck. I have had trucks that overheated due to the winch causing a distrubance in the air flow. Just a thought.

 

[opel]

Interesting..... The funny thing is it will do it overdrive , drive or second. If I hold the boost at 12 to 14 pisi it will sta y about 3/4 way up the temp gauge no matter what gear. The torque converter is a high perf/ heavy duty made by Automatic Transmission Systems and works really well. The transmission is not heating much, by that I mean it will run 160-180 with just the truck down the highway. The truck will not heat by itself no matter what ya do, just when you get on grade or flat with trailer and lean in to it and go above that 14psi boost. The winch is interesting,never thought of that. I will look in to that. Thanks.