Really hot weather testing climbing a mountain

[TrackAire]

Not sure if anybody is interested in this experiment but I'd figure I post it.
On Sept 6th, my town of Vacaville had one of its hottest days ever reaching 115 degrees. I'm semi-done building up my 1993 Explorer and wanted to see how it would handle an intense hill climb in very hot conditions....essentially worst case scenario. I loaded up my truck with some gear, tools and lots of water and snacks in an ice chest since most of the climb has no cell phone reception. If I had an issue, I would be out there for a while until help would arrive. If I wasn't back home by 5:00 pm my son knew to come find me. The road in question is called Mix Canyon and climbs up a mountain range between Vacaville and Napa. The climb starts at 300 feet elevation and the ambient temp was 110 degrees at 2:30 pm. My first stop to measure the top radiator hose with a infrared thermal gun was 4 miles up the hill at 2000 feet of elevation. The drive takes approximately 15 minutes on a very curvy single lane road. I wanted to make this run as realistic as possible so I ran the air conditioning at full blast to test the system and for me to stay cool. At the 4 mile mark, the upper radiator hose was at 224 degrees. The dash temp gauge is rather useless since it says NORMAL for a lot of the sweep. I noticed that just before I stopped, the needle was very near the middle and only moved up slightly more as soon as the truck came to a stop and the air flow stopped. After the first temp reading I continued up the mountain but the climb eased up and I hit 2600 feet elevation at the top of the ridge. Driving along the ridge road my temps were around 215 degrees when I checked them. Interestingly on the away down the mountain I put the truck into low range to save the brakes (I have manual front hubs). Just before the bottom of the hill I stopped and check the temps....180 degrees and it was probably 111 to 112 degrees at that point. My final test was driving back to my office on the highway for about 10 miles at 65 mph @ 2500 rpm with the AC on. At this point the ambient temps were 112 degrees. I pulled over and recorded water temps about 218 degrees and climbing. Stopping the air flow really showed a potential weakness here. I'm concerned about super hot ambient temps when in first gear, low range climbing out of a steep canyon trail. I may look into a high quality electric fan set up. But the truck did the experiment with no ill effects...ran great, no issues, etc. I did run 91 octane to try to avoid pinging...normally run 87 octane.

Here are the modifications to the truck:
89k original miles, engine bone stock
5.13 gears with lockers front and rear
35x10.50x15 tires
5.5" JD lift kit front, springs over axle on rear
New radiator, water pump, fan, hoses and belts
Heavy duty fan clutch (hate it)

I think I'll be adding an auxiliary water temp and transmission temp gauge just to be on the safe side....I hate not knowing the actual temps.

 

[DintDobbs]

@TrackAire Nice testing and records, this could be useful info for 1st and 2nd-gens!

I don't care what the external temp is, I only run the air conditioner when I have passengers. Here it rarely gets above 100 except in the middle of summer, but the high humidity and dead forest air can drain power output significantly, meaning you want to keep the RPM's up for torque. On the trade off, the elevation is low, so the higher air pressure compensates. When I took my 2nd-gen out on the beach this summer (stock motor, 5R55E O/D off, 4.10's), the temperature gauge rarely got higher than the half-way mark, after about an hour of steady half-throttle on the sand, also with the A/C on. I don't know what Ford did with the cooling on these early Explorers, but their newer models need to take a hint!

 

[Kesp4.0]

Nice job- not only on the stress test but on recording some data to go with it. My anecdotal experience with my first gen is that it is (was) tough as nails. I remember regularly driving it out on dirt roads in the SoCal high desert in 100+ degree temps and leaving OD on (I didn’t know better at the time) and crawling around at slow speeds in the desert heat, fully loaded with camping gear and heavy items and friends and driving up and down hills. This was when my 93 was ten years old and had ~140k miles on it. I did it for years until I graduated college and a full time job kept me from doing those things anymore. By that time the Explorer had about 190k on it and it never failed me.
300 ft asl to 2000 ft in 4 miles? Not a bad test. Sounds like it passed!

 

[joney]

Impressed! With your scientific test, and your 93 Explorer!

 

[~X~]

The sound of the fan with a heavy duty clutch can be annoying.

Not as annoying as a blown head gasket.

 

[TrackAire]

The sound of the fan with a heavy duty clutch can be annoying.

Not as annoying as a blown head gasket.

I actually don't mind the sound/noise that much but my concern is in very hot conditions while in first gear low range and climbing out of very steep canyons it won't move enough air to keep the truck and tranny cool. We use this truck to get to gold claims in Norcal and some of the climbs out of the creeks gain elevation of 800' to 1000' in 1/2 mile. Add to that that the trails are overgrown with manzanita brush and there is not even a hint of breeze when you're in the thick stuff, it's stifling. I'm going to research what others have done using an electric fan. The two best that we've found at work that actually put out the CFM they claim are Spal and Maradyne. Most of the other units are not putting out anywhere near what their ad's claim.

 

[Nadams01]

Good testing, long story short our coolant temp gauges are not always going to be the most accurate, due to the simple ohm style of setup and mounting a coolant temp sensor in the most accurate position is difficult. If the gauge goes out of normal and gets to the H it's hot. Mine goes out of normal and into the H range at 220, then will cool down to the a in normal after some rest. I used a thermal gun for my testing around the thermostat. Electric water pump and fans are a great idea. I set a system up for a 64 ranchero at the shop, used a potentiometer and a controller from the temp sensor to slowly ramp the waterpump and fans up at a certain temp completely independent from engine rpm. I will be doing that setup come next summer to see how it goes.

 

[BKennedy]

How old is your fan clutch? I recently replaced mine with a severe duty Hayden. Also replaced the water pump and hoses just because. My 1994 used to get real hot on long uphill grades. Now, it usually won't get past the O in NORMAL. I hardly ever run the AC because it sucks too much power. The new fan clutch is noisy at under 35 MPH, but as it was so well stated earlier, "not as annoying as a blown head gasket".

I looked at electric fans, but most of them are too thick to clear with my 3 core aluminum radiator.

 

[TrackAire]

How old is your fan clutch? I recently replaced mine with a severe duty Hayden. Also replaced the water pump and hoses just because. My 1994 used to get real hot on long uphill grades. Now, it usually won't get past the O in NORMAL. I hardly ever run the AC because it sucks too much power. The new fan clutch is noisy at under 35 MPH, but as it was so well stated earlier, "not as annoying as a blown head gasket".

I looked at electric fans, but most of them are too thick to clear with my 3 core aluminum radiator.

It is a new Hayden HD version, water pump new, plastic fan and radiator are new. I replaced everything last year when I was building up the truck not due to mileage but just age. My condenser is very clean and the fins are straight. I agree that the AC sucks power, but I wanted to push the system to find any weak spots. In tough conditions I can always turn off the A/C and do other things to help lessen the load, etc.
I will be researching an electric fan option....I'm not a fan of electric fans but I may try a system out.

I am running a new stock radiator, not an aftermarket unit....not sure if there is an aftermarket unit that may be better. My temp "gauge" went to between the R and M in NORMAL.....my temp ready showed 224 degrees there. At the O, my temp reader shows about 180 degrees. Definitely time for an aftermarket coolant and transmission gauge to keep track of what is really going on.