2500 Overheating when towing

[02Yukon2500]

The highest airflow wins. If the fan clutch or efan has a lower cfm than the incoming air from driving forward then incoming air wins and vice versa. So if you are moving forward at 55mph and at that speed there is 2000cfm of air coming in across the radiator and the fan(s) put out 850cfm of air then there is no air moved forward from the fan(s) because the 2000cfm of incoming air overcomes the 850cfm. The fan(s) take care of business at idle and lower vehicle speeds.

This is my thinking too. If right, then the electric fans should be better in all situations except for low speed with high RPM for long periods. I live in a rural area with no big mountains, so I see that situation rarely.

I think I'm going to go the 05-06 efan route. Now, I just have to collect the parts and get a tune to enable it. If I'm going to the mountains, I guess I'll just drive my Duramax pickup...

I'll update with my results once I've done all the upgrades.

Danny

 

[fasteddy]

I'll watch to see how you get the cooling temps down. I kinda have the same problem with towing larger loads, 6000lbs+, with my 03 Tahoe.
It has a built 6.0L and trans and powertrain is not a problem. I'm so impressed by it towing capability. But this week it was 110+ degrees in AZ and the stop lights and uphills were stressing the cooling system.
Stop lights because of reduced airflow from Mech fan. I haven't done efan upgrade yet. That problem is easy. But keeping coolant temps low on uphills at 60mph+ is harder as efans won't solve that.
I kept my coolant temp around 200 by turning off the AC compressor. I didn't think the AC compressor would make that big of a difference, but it did. But towing on 115 degree sunny day without AC is unacceptable, very unacceptable! My 6.2 Sub handles towing in heat OK so maybe it's the efficiency of the AC compressor or the 6.2 radiator. The GM 6.2L/10Speed powertrain is a towing machine.

FYI, the trans and engine cooling are joined at the radiator. One can affect the other. If the engine coolant is hot your trans fluid will be hot too and vice versa.

Good luck! I'll let you know if I figure something out.

 

[S33k3r]

This is my thinking too. If right, then the electric fans should be better in all situations except for low speed with high RPM for long periods. I live in a rural area with no big mountains, so I see that situation rarely.

I think I'm going to go the 05-06 efan route. Now, I just have to collect the parts and get a tune to enable it. If I'm going to the mountains, I guess I'll just drive my Duramax pickup...

I'll update with my results once I've done all the upgrades.

Danny

Something is eating at my memory, but I can't remember, sorry... That said, it is something about the '08 efans being a little larger or flowing a little more air than the '05-'06 efans. You might want to look into that.

 

[Geotrash]

Check your baffles on either side of the radiator. They deteriorate over time and others here, including me, have found this to be a big part of resolving cooling related issues on my '12 1500. When the baffles are missing, air gets pulled through the radiator by the fan, heated, and pushed back around the ends of the radiator where it gets pulled back through the radiator again. I sealed mine up with Coroplast sheets cut to fit. Another 2500 owner here reported recently that fixing the baffles solved his cooling problems as well.

On the GMT900 series, the exterior temperature sensor sits just forward of the baffle, and when the baffles are missing, it will read erroneously high temps of +15-20º above true ambient, so it's an early warning indicator that your baffles may need attention.