ceedeeyess

I have a 2008 F150 HD with the 7 lug axles, 11,000# towing capacity. Recently purchased a 28' 5th wheel camper, dry weight 6400. Calculated loaded weight of between 7200 and 7500 pounds with full water tank, supplies, etc. Travelling between 6,000 feet and 10,000 feet elevation, cool morning. Truck did fine for the first 45 minute 'gentle climb'. Got into the first hard climb, about 2 minutes in second gear at 4,000RPM and the temp gauge went from dead center to overheated with the attendant beep and warning, no check engine light.


Question would be two-fold: why would the gauge never move, and what can I look for in terms of cooling issues? Truck only has 38,000 miles and has been well maintained and never done any heavy lifting since I bought it with 22,000 miles. I have considered that the RanchHand grill guard may be limiting airflow, but I can't see where it would restrict it that much. Any help would be greatly appreciated.

smokeywren

Because it's not an analog gauge - it's an "idiot gauge". If your 2008 is similar to my 2012 coolant gauge, then it has three or four ranges, and it jumps from one range to another. It probably has a low temp range, in the lower half of the white zone, a normal operating temp range around the halfway mark in the white zone, maybe another "high but okay" range at the top of the white zone, then a PAY ATTENTION! zone in the yellow range. The red range means TOO HOT, so stop and let the engine idle while the radiator does its thing to cool the coolant back down some.

That coolant gauge is fine if you learn to watch it like a hawk when the needle gets up close or into the yellow zone. DO NOT allow it to get into the red zone. If you're climbing with cruise control. kill the cruise control. Then back off the go pedal to slow down to about 45 MPH, then downshift to raise the engine RPM to over 4,000 RPM so the coolant will flow faster through the cooling system.

Your tranny temp gauge is more important. The tranny will probably overheat before the engine coolant temp gets into the red zone. It too is an idiot gauge that you NEVER want to allow to go into the red range. The tranny temp yellow range is too hot, so stop and idle the engine at a high-idle RPM of about 1.200 RPM until the tranny cools down so the gauge is back into the white zone.


Then when you get home, have the tranny drained and flushed with synthetic ATF such as Mobil 1.

What to do to increase cooling capacity? Probably nothing for engine coolant temp, other than be certain your coolant is 50% distilled water and 50% antifreeze. For tranny temp, you can replace the oil-to-air (OTA) heat exchanger (tranny cooler) with a bigger one from the aftermarket.

ceedeeyess

Thanks for the input smokeywren. Unfortunately not much help in terms of the guage situation as mine isn't the same setup as yours and actually does move up incrementally as you would expect an analog gauge to do. Additionally, I don't have a tranny tem gauge. I will, however, look into the synthetic tranny fluid.

Feathermerchant

And you can buy a transmission temperature gauge.
Ford makes several oil to air coolers for transmission. My 2011 has both a cooler in the radiator tank and external in front of the radiator.
Could your radiator be partially plugged?

DieselDawg

Get a tune using a Livewire and you can set up gauges on the Livewire...plus you will get a better running truck. Just one easy (maybe not that cheap) solution.

Boulevard

Not enough miles is just as bad as to many and I suspect that the radiator is either plugged, the thermostat is faulty or the water pump is failing. Changing all 3 will not break the bank and will at least answer that end of the problem. I would also look at a true cooling system clean and flush to see if you can get any crud out of the engine.

It is hard to tell if the transmission is overheating because you do not have a guage but maybe it is time to get one although my first step would be to get a big honkin' aftermarket transmission cooler and I would get it in there.

Velosprout

I would suggest a Scanguage II or DashCommand for a Bluetooth phone guage as a way to monitor your temperatures and other specs. The HD payload package included a transmission oil cooler, and you are well within the truck capabilities. I suspect the thermostat first. Have a shop check out all of the cooling system instead of just replacing parts.
http://www.scangauge.com/products/scangaugeii/
http://www.palmerperformance.com/pro...mand/index.php

acadianbob

Well, your gauge IS managed as smokeywren indicates. It fakes you out during the warmup but is definitely managed. Ford has done this with their gauges because too many people who don't understand mechanical devices freak out if the temp moves up at a stop light on a hot day. Same with oil pressure drop in the same circumstances.

I have the ScanGauge that a previous poster mentions. It works great and gives you trans temp as well. If you get this device, you will realize that your gauges are indeed managed.

Feathermerchant

Unfortunately the oil pressure sending unit is a switch so the scangauge can't help you there. Sheesh (to Ford).

Suzuki14258

Check your fan clutch