Coolant temperatures while towing

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South VA

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I thought it might be helpful to follow up on a few loose ends in this thread (which I also discussed in my build thread):

The PO confirmed that this beast does in fact have a new radiator, along with new upper and lower radiator hoses, plus a new radiator cap. So far so good.
My plan is to do a drain and flush, and replace the thermostat with the newly purchased GM one. I'll probably use a 50/50 premixed antifreeze.

Upon inspecting the cooling stack (I learned a new term!), I found the fins to be clean, unbent, and one can easily see through them. Nonetheless, I'll blow some compressed air through them, with reduced pressure to ensure fin safety.

It turns out that my auxiliary fan does work. After a long drive I visually checked it while it was parked and idling, and the ECT was just below 200º F. The fan shut off when I turned off the ignition.

Still haven't decided on a fan, but I'd want a simple bolt-on solution. I'm not 100% clear on what part #s I would need to make that happen.

Lastly, even though this thread was about engine coolant temperature, the topic of transmission fluid temperature did come up and was discussed enough to warrant passing along what I learned from Trent, the guy that rebuilt the transmission, plus the GM SM. Trent said that the TFT really shouldn't go much above 230º F. The GM SM, Book 2, Page 7A-370 states that the normal operating range for the 4L80e is 90º C to 115º C, or 194º F to 239º F, depending on load.

Our next trip is in early July, again to the mountains; and I will report back how it went, temperature-wise.
 

Schurkey

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If you buy premixed "50/50" antifreeze, you're paying too much--and risking not having enough freeze/boil protection if you don't remove all the flush water..

Get the concentrate anti-freeze, and mix it yourself. Figure out the total cooling system capacity, perform your flush. Drain the flush water by removing whatever is sealing the block drain holes--plugs, or knock sensor, or whatever. Reinstall the plug(s) or knock sensor.

Pour 1/2 the total capacity of the system of anti-freeze FIRST, reserving a little for the overflow bottle. Then top-off with water. That way you're guaranteed to get all the anti-freeze needed into the cooling system, even if you don't get all the flush-water drained out.

The Lisle radiator funnel set makes this easier, including the air-purging when the vehicle is first fired-up.
www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY/ref=sr_1_5?
 

South VA

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If you buy premixed "50/50" antifreeze, you're paying too much--and risking not having enough freeze/boil protection if you don't remove all the flush water..

Get the concentrate anti-freeze, and mix it yourself. Figure out the total cooling system capacity, perform your flush. Drain the flush water by removing whatever is sealing the block drain holes--plugs, or knock sensor, or whatever. Reinstall the plug(s) or knock sensor.

Pour 1/2 the total capacity of the system of anti-freeze FIRST, reserving a little for the overflow bottle. Then top-off with water. That way you're guaranteed to get all the anti-freeze needed into the cooling system, even if you don't get all the flush-water drained out.

The Lisle radiator funnel set makes this easier, including the air-purging when the vehicle is first fired-up.
www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY/ref=sr_1_5?
Thanks! What you said makes sense. I'm sold.

As for the Lisle funnel, the one you linked has the standard adapters. They list one with a GM adapter, right next to it. Should I go with the GM one, or will the standard set work?
 

HotWheelsBurban

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Thanks! What you said makes sense. I'm sold.

As for the Lisle funnel, the one you linked has the standard adapters. They list one with a GM adapter, right next to it. Should I go with the GM one, or will the standard set work?
The GM adapters might be for the 2000-up models that have a screw on cap for the overflow tank. Our '06 truck had that, the overflow tank is pressurized because that is the access to the cooling system. Radiator has no cap.
I'm not looking at the tool, but I'm going to venture that guess....
 

South VA

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The GM adapters might be for the 2000-up models that have a screw on cap for the overflow tank. Our '06 truck had that, the overflow tank is pressurized because that is the access to the cooling system. Radiator has no cap.
I'm not looking at the tool, but I'm going to venture that guess....
Thanks. That makes sense. I ordered the gm/ford/vw kit anyway, before your response, since my GF has a Ford Ranger that probably needs the cooling system flushed too.
 

South VA

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Ok so I had a typo on my comment about the Fan. It should be a 2018 2500HD with a 6.0 gas motor. The Fan PN is 621111 made by Dorman. It’s a direct bolt on with no mods.

Thanks for this! So, just to be confirm, this fan will fit a ‘96 7.4 with a four bolt fan clutch?

Here's what mine looks like:

Edited to add: RA has three fans that come up under that part number. Does the Dorman hold up well, or should I consider the more expensive VDO/Continental?

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