[badseed]

I recently purchased a 2007 Chevy k1500 Z71 with 100k miles. Overall I really like the truck except that today when I was driving to a friends house following a line of traffic at slow to moderate speeds 40-45 mph up a long grade, I noticed my engine temp was getting high. The truck has an edge programmer (yes I know BB is better) which started to flash at 226 degrees and the trans was right around 210. I couldn't believe it but I turned around and went home. The temps are normal when idling, and driving on flat roads but they climb quickly when going up any grade.

The truck has a 7" lift with 35x12.5x20 Toyo MT tires and from what I discovered, the Z71 package has 3:73 gears which should be acceptable with 35's.

I immediately thought it was fan clutch but I noticed that I have electric fans. The coolant is almost full, about 1" below the full mark in the reservoir. There is no leak from the water pump so what else could it possibly be? I was looking at upgrading the gears but as it sits I should be able to drive empty up a hill without it getting hot. PLEASE HELP!!!

 

[Graystone]

Are your fans turning on?

 

[badseed]

I assume that they are working fine because it cools off quickly when not under load and the temp does not rise when idling. I will verify...

Other pieces of information that may help; it was about 90 degrees outside, A/C was blasting, and the factory temp gauge verified what the edge showed. The edge was only set on level 2 which is supposed to be for improved shifting not much in the way of performance. Once I turned around and starting heading home the temp dropped right back to normal 195-200.

 

[Graystone]

Did you open your radiator cap to check if there was fluid in there?

I would never assume

 

[badseed]

Are your fans turning on?

Whats the quickest way to verify that the fans come on?

 

[Graystone]

turn the truck on and watch

 

[badseed]

I took the truck for a hot lap and checked the fans at 195 degrees; both of them were working. As far as the radiator goes, all I have it a reservoir cap. From what I understand, these trucks dont have a traditional radiator cap and work off of pressure. I opened the reservoir and there was a little pressure release. Although I didnt drive up any hills, the truck stayed at 195-198 according to the edge and 210 according to the factory gauge.

 

[Mr. 960]

those fan have a medium and high speed; at least on my 06. you can realy hear it when they start roaring at full speed. This may be your problem.

Mr. 960

 

[badseed]

At what temp does the high speed kick in? Hopefully someone with large tires and factory gears can chime in to let me know if these trucks are so weak that you cant run bigger tires on factory hears and expect to drive up a grade without overheating the motor. I really need to figure this out ASAP.

 

[FiestyZ71]

At what temp does the high speed kick in? Hopefully someone with large tires and factory gears can chime in to let me know if these trucks are so weak that you cant run bigger tires on factory hears and expect to drive up a grade without overheating the motor. I really need to figure this out ASAP.

I think mine kick on high at 190 or when AC is on. But my tuner might have adjusted the temp.

 

[Graystone]

It's not your lift and tires doing it. There is something more. Have you flashed to your stock tune and see if the problem is still there?

 

[badseed]

I was going to do that but all the edge only shows level 1-4 or "customize stock". Can I just unplug the edge and everything will restore to stock, or will it keep the last edge program? I tried to smog the truck today and the tech said that it showed EVAP not ready. Does that help explain anything?

 

[Graystone]

I don't know how the edge works exactly so I have no idea. You should be able to go back to stock program and disconnect it.

 

[badseed]

I put the edge back to stock and I will take ti for another hot lap today to see if that helps at all. I'm going to take it in on Wednesday and have the cooling system checked if removing the edge doesnt help. I would hate for there to be a problem with running the edge at level 2; thats pathetic.

 

[Graystone]

I put the edge back to stock and I will take ti for another hot lap today to see if that helps at all. I'm going to take it in on Wednesday and have the cooling system checked if removing the edge doesnt help. I would hate for there to be a problem with running the edge at level 2; thats pathetic.

If it was I would say it was a tuning problem not your truck.

There are plenty of people running 35s on these trucks and don't have this issue

I ran 33s for years with 3.42 towing and never had this problem

 

[Mr. 960]

Both my trucks have the "auto climate control" so the A/C is ALWAYS on. My fans only hit high speed when I shut the truck off and turn back on after a few minutes on a very hot day at least 90* plus. Other then that they are always on low speed.

Mr. 960

 

[Chitter]

Have you checked your thermostat? Sounds like it isn't opening all the way only allowing minimal flow. Had a car do the same thing you are experiencing and it was the thermostat.

 

[Graystone]

Have you checked your thermostat? Sounds like it isn't opening all the way only allowing minimal flow. Had a car do the same thing you are experiencing and it was the thermostat.

Best suggestion yet.

 

[Chitter]

Best suggestion yet.

:shake:

 

[badseed]

I will likely replace it just to be sure. Is there any advantage to buy a lower temp thermostat?