Coolant, Trans., Oil Temp limits
 

So I've towed my 24' car trailer with my car in it for several thousand miles without any issues. Trailer loaded weighs 8000-9000lbs and I tow mostly in MI where its flat or flatish. 2007 EL has done just fine, until this past weekend when towing just like I normaly do at 60-70mph the A/C shut off. No warning lights, temp gauge reads fine. Freaked me out. Manual says this happens when the motor is running hot but the gauge was right in the middle, never moved. I pulled over shut it off, started it up and it ran fine WITH A/C back on. Finished the rest of the trip just fine.

It always concerned me that there isn't much in the way of gauges on these vehicles so I bought a Edge CS to monitor things. So now I can monitor oil, water and trans. temps no problem but what sort of numbers should concern me? When should I worry and slow down?

Well that was a waste of time.

The entire reason I bought it was because the Edge website said it would work with my 07 Expedition. Well it doesn't and after a couple hours messing with it and 2 calls to their tech support it doesn't and they 'apologize' for the typo on their website.

Guess I'll just be winging my trans. temps and keeping my fingers crossed.

I have an Aeroforce Interceptor scan gauge on my '07 Expedition for towing. Never got around to mounting it in a pillar post or dash pod, it just sits velcroed on the dash in gauge mount. Just plugged in.

http://thumb4.webshots.net/t/58/758/...4HPdtop_th.jpg <--- that's a link.

You got the HD tow package? 9000 pounds is the maximum towing capacity, but with nothing but you in the truck.

-- Chuck

Your A/C shutting off is a glitch these have. Both my 07 and 08 did/do that every once in a while. Have to turn off the ign then restart it. I would still monitor temps when towing that much, you are pushing the limits.

Yeah, HD tow and the EL so I think 8700lbs is the max. Trailer is 3800lbs empty and car is 3000lbs plus stuff. I doubt I hit the max. but its close a few times a year.

I'm going to order that gauge, thank you for the link! What sort of numbers should make me concerned?

A couple of opinions on trans temp:

http://www.txchange.com/heatchrt.jpg http://www.alamomotorsports.com/pmc/...es/PG02-R1.gif

and one for the metric folks:

https://farm1.staticflickr.com/95/24...be7da9ec_b.jpg

-- Chuck

I don't think there's a sensor for engine oil temperature so don't blame edge, but there is a sensor for CYLINDER HEAD TEMPERATURE. I have the MSD Dashawk, which I think is discontinued now. I found that my transmission temperatures got just as hot with just me in the Expy in stop-and-go Phoenix traffic as I did fully loaded with the family pulling a 31' travel trailer (13,000 total weight) up hill in 110°F heat!

Do yourself a favor and weigh your trailer and truck. You can use a truck scale for like $8 or most gravel yards will give you a free non-certified weigh.

Just finished a 350 mile trip towing my 24' car trailer loaded with race car and usual stuff. First trip with the new Aeroforce Interceptor gauge plugged in. I can sleep in peace again now. Ambient temps were in the 90's, Trans. temp peeked at 208F in stop and go traffic getting to the highway then settled down to 185F once cruising at 60-70mph. Coolant sat around 197-200F. Got 10.1mpg with a good tail wind on the way home which is a new record!

I'm pretty happy. Towing at the upper limit of the EL's capacity and the Ford Engineers seem to have the HD trans. cooler size sorted. Raced all weekend with my GM engineer buddy who's friend in Powertrain said if he sees temps in his Suburban around 250F to worry. GM and Ford co-developed the trans. in our trucks so I think 250F should be our new 'worry yardstick'.

From watching the gauge I think there's a 170°F thermostat in the transmission line as she warms up to that temperature in cold weather and stays there.

In warm weather, including the hot 100°+ temperatures we've had in the region the past month. the truck transmission temperatures run 90°F above ambient air temperature in normal driving and 100° or so above ambient with towing. Only a 10° increase with the camper on the back. Peaks not included and she drops back to normal range very quickly.

-- Chuck