New to us TV overheating??

jaycocamprs wrote:
What you have is normal for a LLY. I know, I have one. What is happening is normal for all trucks, work the engine on a hot day the fan cools things off. But the 04 & 05 LLY trucks have a cooling capacity that is only marginal, the 06 trucks have a 30% larger radiator. So the fan comes much sooner and at lower ambient temperatures. And worst of all, the fan won’t even hold the temperatures in check on a long hard pull. We bought our 05 because we wanted to buy a trailer like we now have, and knew our 6L gas 2500HD was enough truck. What we got was a truck that couldn’t do the job on a 100 degree day. Like ib516 said, go to the Diesel Place and read. Then get one of these.

We put on of these Ron Davis made auxilery radiators in our truck (the picture is not mine) and have not looked back.

Thanks for your input! Some just don't understand SW heat in summer, brutal.

What you have is normal for a LLY. I know, I have one. What is happening is normal for all trucks, work the engine on a hot day the fan cools things off. But the 04 & 05 LLY trucks have a cooling capacity that is only marginal, the 06 trucks have a 30% larger radiator. So the fan comes much sooner and at lower ambient temperatures. And worst of all, the fan won’t even hold the temperatures in check on a long hard pull. We bought our 05 because we wanted to buy a trailer like we now have, and knew our 6L gas 2500HD wasn't enough truck. What we got was a truck that couldn’t do the job on a 100 degree day. Like ib516 said, go to the Diesel Place and read. Then get one of these.

We put on of these Ron Davis made auxilery radiators in our truck (the picture is not mine) and have not looked back.

nremtp143 wrote:
Also keep in mind that the gauges in all of our trucks are just IDIOT lights. Meaning by the time they move, something is really wrong. If you want to really know what is going on with the truck, buy a gauge like the Edge Insight CTS #83830 here Edge Monitor IT will show you exactly what the truck computer is seeing and takes out the "wonder if everything is ok" questions. You watch the info in real time. By the time most gauges show a change, damage to your truck has probably occurred. It will monitor several parameters at a time and you can check it at a glance. I love mine..This is NOT a programmer...a monitor only.

What he said... THe engine temp gauges on the GM trucks are known for being very innacurate. You can get accurate readings but don't need to spend the coin on an Edge Insight to do so. If you have an Android based SMART phone you can download the free Torque app and pick up an OBDII ELM bluetooth transmitter off of ebay for around ~$20 that plugs into the OBD port (below dash) and will give you accurate water temperature readings.

The first time that I heard the fan kick in on our Dmax, it scared the living daylights out of me. I initially thought that there was something wrong with the engine but I shortly realized that everything was ok. It's good thing that the fan isn't going all the time because you wouldn't be able to hear yourself think inside the cab. I have even noticed that the fan will kick in on a long downgrade. Why; I'm not sure, but I think that it's adding negative horsepower to assist in slowing down the truck and trailer.

Normal condition on the truck.

X2 on the edge insight CTS. Have one - always good to see how hard the engine is working - boost, EGT, engine and trany temps.

On the CTS the tranny temp matches the DIC (both are digital - makes sense). The engine coolant on the CTS is about 20 to 25 degrees less than the gauge.

Also keep in mind that the gauges in all of our trucks are just IDIOT lights. Meaning by the time they move, something is really wrong. If you want to really know what is going on with the truck, buy a gauge like the Edge Insight CTS #83830 here Edge Monitor IT will show you exactly what the truck computer is seeing and takes out the "wonder if everything is ok" questions. You watch the info in real time. By the time most gauges show a change, damage to your truck has probably occurred. It will monitor several parameters at a time and you can check it at a glance. I love mine..This is NOT a programmer...a monitor only.

I have an 06. Tow with the tow button in.
Shift it yourself and keep it out of overdrive (6th gear)
Shift down to the next lower gear at 2200 RPM.
Get an EDGE or a EFI tuner, Edge is the safest bet for towing.Run in TOW mode. Install it and a Pyrometer probe and you can then, more accurately, observe water, transmission and exhaust temp.
The fan should come on at 220 and run until temp is below 215.
They are big with a lot of blades so they are noisy.
Buy a set of Parker transmission cooler lines and replace you lines as they are the worst design in the world and you'll find puddles in your drive.
http://madjackdiesel.com/allison-1000-transmission/parts-pans-etc/diesel-race-parts-transmission-cooler-repair-lines-2004-5-lly-2010-gm-duramax-pick-up-trucks.html
A pump rub kit. http://www.merchant-automotive.com/transfer-case-pump-upgrade-kit.aspx Read up on it.
Then buy a pair of Timken fron hubs so when they go out you'll have the good ones as Chevy hubs last about 50K miles. Best economy is 65MPH towing.

If you're new to the LLY Duramax, you might want to See this.

My Cummins engine fan start up sounds like we're preparing for flight.

If the gauge does not move... it is not overheating.
Fan is normal.

Just because the diesel does not rev up like a gasser does not mean it is not working hard.