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coolant temp question

STEVE53

STEVE53

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wasilla, ak
Hey there fellas. I just removed and cleaned out my radiator today because I think that my engine is running a bit hot. While cruising about 55 mph, temp will get up to 210f, sometimes a shade over according to my gauge without pulling a load. I flushed out my radiator inside and out and am sure that it is very clean. Ambient temp was around 60f today. I am wondering if maybe my fan is not kicking on when it should, I cannot hear a "whoosh" sound when the fan kicks in. Is there a way to test the thermastatic control on the clutch, or does anyone have any idea why I am running hot? Thanks for any help.

Steve
 
If your not hearing a whoosh it's probably not working. 95s have about the poorest cooling system outhere. Also which thermostat are you using. If it's not a FACTORY GM you will have problems. If finances allow look at Heath Diesels Cooling upgrade. It has almost double the gpm on the waterpump of a stock 95 and improved fan. These trucks run hot towing but empty you should not be having a problem. Did you remove and clean a/c con and oil/trans coolers as well ? It makes a big difference.
 
I checked the thermastat that was on the truck and it operated smoothly, but I did not actually test its function with hot water. Is the "whoosh" sound of the fan hard to miss? Maybe I am just not noticing it over the sound of the engine and wind noise (while driving).

I did not remove the tranny, oil coolers or the condensor, but I blasted them while the radiator was out and I can see through them pretty well.

Is there a way to adjust the thermastatic coil on the clutch to make it engage earlier? I was messing around with a fan and clutch I have for another truck and there is actually another slot where the coil tang could be placed to adjust the kick on temp....I think:rolleyes5:.


Steve
 
One thing I forgot to mention. When I first drive the truck for the day, I will notice the temp gets up to about 210f, then it will drop all of a sudden down to about 180f, then after I drive for a while the temp drop is not that drastic. I'm not sure if that is the fan kicking on, or the thermastat opening.

Steve
 
I don't think you understood me properly. It does not matter how well the thermostat works, what matters is if it is a working FACTORY GM thermostat. Aftermarket thems like NAPA etc will NOT work properly in a 94-95 single thermostat system. If you have a non stamped GM therm that is a good part of your problem.
 
Acesneights1 said:
I don't think you understood me properly. It does not matter how well the thermostat works, what matters is if it is a working FACTORY GM thermostat. Aftermarket thems like NAPA etc will NOT work properly in a 94-95 single thermostat system. If you have a non stamped GM therm that is a good part of your problem.
Click to expand...

So is the theory behind this that the napa/aftermarket thermostats dont flow as well as the gm's??
 
No, the difference is the plunger that closes the bypass circuit. It doesn't look like a normal t-stat it has a flat disk/plunger with a spring hanging from the bottom side (hot side). I used to have a picture comparing it to a standard T-stat but can't find it now. I'll keep looking...

Here you go, it looks like this. (Courtesy of the Kennedy diesel website/Robertshaw thermostat). Gotta have the right t-stat with the right plunger. I tried a different one once and it didn't work right:
 

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Thats what mine looks like, but like I said, it doesn't say AC anywhere on it. Does an AC have a stamp on it? If it does then mine must be a different brand.
 
On my AC therm. it has a band of rubber around the body.

Towing 16,000 lbs today and my fan didn't need to kick on, when it does you'll know. It scares the hell out of me for a second from the roar.

Leo
 
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OregonHorseTug said:
If it says Robershaw you're probably okay. That's what mine is. Do you have the temperature stamped on it?
Click to expand...

Oregon, You have a 96. Dual Therm IIRC. The single setup MUST have Factory GM nothing else. Change that before you do anything else. Only the factory one properly seals off the bypass otherwise with any other one some of the coolant will not make it's way to the rad.
 
Acesneights1 said:
Oregon, You have a 96. Dual Therm IIRC. The single setup MUST have Factory GM nothing else. Change that before you do anything else. Only the factory one properly seals off the bypass otherwise with any other one some of the coolant will not make it's way to the rad.
Click to expand...

No, I have an early '96. It has the single t-stat (NAPA thinks it's a dual stat, too). It also works great by the way pulling at 19k combined. The Kennedy super fan clutch sounds like a jet engine coming on when I'm rolling up a hill moving slow on a hot day.:thumbsup:
 
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