Truck only overheats going uphill at highway speeds

Hi,

Short answer is no. The MAF tells the computer how much air is coming into the engine so it knows how much fuel to add so that it runs properly.

If you are overheating going uphill more than likely it is due to low coolant, radiator fan is not spinning fast enough, or you have a coolant restriction.

Clearly there could be other causes but we need to find out if the cooling fan is operating properly, after you check the coolant level.

If you have not serviced the coolant in a while it may be a good idea to start there.

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

Let me know if you have already tried some things or what you find with this info. Thanks

Okay. I am not suggesting it needs a fan unless the motors are bad. Also, can you send me the actual codes that you got for each of those sensors?

If those are off and not reading properly it could great a lean or rich condition which can effect engine temperature under load.

Let me know what the codes are and we can go from there. Thanks

Okay, thanks.

P0105 - MAP Sensor
P0120 - TPS Sensor
P0325 - Knock Sensor

These codes could cause issues but not overheating going uphill.

More than likely the overheating issue is on the path that you have been going. Either there is not enough air flow through the radiator to cool the coolant quick enough with this added load or there is an air pocket in the cooling system.

Let's start with the easier one. I would suggest investing in one of these funnels to fill your radiator because it almost eliminates air pockets. However, when you check it jack up the radiator cap has high as possible. Meaning you want the opening to the cooling system (radiator cap) as high as possible so that all air will raise and work towards the cap and then it will exit.

Here is a video of the funnel I am talking about:

https://youtu.be/xYkKW0OyeUc

It is not necessary to drain and fill the radiator again, just open the cap, install this funnel and then fill the funnel about a quarter of the way with new coolant. Jack up the front end closest to the radiator cap and then run the engine so that it gets hot. Just let it idle for about 20-30 minutes after it is hot and make sure the funnel keeps about a quarter full so that if any air pockets open up it will pull in this coolant to fill the gap.

Attached is the diagrams for the MAP sensor. I suspect if you fix this one, it will fix the other codes as well. However, let's keep this post to the overheating issue. If you want to tackle these codes then let's get a new post started because we need to keep it to one topic per post so others can find any answers we come to for each issue. They won't know to look for a MAP sensor issue under an overheat heading.