6.2L Temps

[BobQ]

I took a ride in the foothills a couple of weeks ago and had the coolant temps crept up a bit on me while climbing a short grade. The outside temp was about 95 or so and the grade was probably around 3% or so. I was going along fine at about 45-50 mph while climbing and looked down to notice that the temp gauge had rose rather quickly to just over the halfway mark (it usually sits at about the 1/4 mark). Is this normal to have the temps climb so quickly? I'm new to 6.2L's so I'm not quite sure. Also, I wasn't pulling or hauling any loads and the A/C was off the whole time. I was in 4th gear (SM465) and the EGT's were about 875 during the climb. The truck is bone stock and has a new 180 degree Mr. Gasket (Robertshaw) thermostat.

I do have one of the rare factory 7-blade fans that I picked up at the junkyard and I'm thinking that I should replace the stock 5-blade with it. What do you guys think?

Thanks.

[HammerWerf]

Bob,

The expirence of the temperature rising is normal. I see it every time I go either on the freeway or up into the hills. When climbing up some of the 10 - 12 % grades on dirt, I will sometimes stop and let the engine idle to a more normal temp. Now the above info is with a fresh radiator.

In the 6.2-6.5, the prechamber is located in the water jacket in the head.

When My Crewcab rad was on its last legs, the situation you described was more common. Check the condition of the inside of the rad. If you see white crusty looking growths on and near the tubes, it's probably time to replace the core. I currently have two different radiators in my pickups. An Aluminum one in the crewcab (Visteon # 850) and a copper-brass high performance unit by Craig Manufacturing from down in LA. From my observations, the Craig unit is better at handling the heat rejection, especially at high ambient air temperatures.

The 6.2 really like a clean radiator to keep cool.

HammerWerf

[Robyn]

Make sure the area between the Radiator an d the AC condenser is clean and the Radiator can flow air well too.

The fan clutch should come on if the temps get up to about 210F

These radiators are marginal when NEW and when they get a lot of time on them and clog up inside from goop they wont get the heat out like they should.


Robyn

[BobQ]

Thanks for the information! I'll take a look inside the radiator and see what it looks like. The truck only has 65,000 miles on it and I know the radiator hasn't been touched.

When I was climbing, I didn't hear the fan clutch on the original 5-blade fan kick in, but the temps didn't rise any higher. I think I might stick that 7-blade fan on as extra insurance too.

Thanks again.

[Robyn]

Total miles is not always an issue. TIME is
This is an 83 truck, right ???? Long time since this old girl rolled off the assembly line.

Dirt, bugs and other crap in the fins as well as the "Solder Bloom" inside the core can cause flow issues. (should have a copper brass radiator in that vintage)


Keep us posted

Robyn

[BobQ]

Yep, it's an '83. Well, the weather is actually starting to cool down quite a bit now. It doesn't look like I'll be able to duplicate the run up the hill with hot weather for quite a while, but I'm still going to check things out.

Thanks again for the info.

[raunch]

Thanks for the information! I'll take a look inside the radiator and see what it looks like. The truck only has 65,000 miles on it and I know the radiator hasn't been touched.

When I was climbing, I didn't hear the fan clutch on the original 5-blade fan kick in, but the temps didn't rise any higher. I think I might stick that 7-blade fan on as extra insurance too.

Thanks again.

Regarding the fan clutch, I just installed a new one and I cannot hear it kick in. The only way I know it's working is I can see the temp gauge drop 5-10 degrees (depedning on circimstances) very quickly. My truck is also an '83 with similar cooling issues. The factory gauge did not work very well to really tell what was going on, so I installed a mechanical Autometer temp gauge. It is very responsive and accurate, and there is no question as to what is going on with the motor temps.

I've been thinking of looking around for one of those 7 blade fans. I had my hands on a 9 blade Eaton, but it was for a serp drive and rotates opposite of my v-belt set up. Anyway, I am curious to know how the 7 blade performs.
Raunch