Engine temps.

[Jackpine]

I agree with Lars 100%. When I tow my trailer up a long hill (like the passes in the Colorado Rockies, or the 8000 foot climb we'll be doing tomorrow when we take our 3600# trailer up to Mt Graham here in AZ), I regularly see 214-216 on the CHT. I simply don't monitor the ECT, since it's inferred. And, like you, my dash temperature gauge NEVER moves above "slightly below the halfway mark".

If you want a real thrill, monitor the oil temperature (if you have that capability). I did for a while, but it was bad for my nerves, so I quit.

- Jack

[BlackSTX]

I'd hate to imagine what the oil temps looks like, I never looked, but will have to when I get mine back.
Also, I didn't realize the ECT was actually inferred.... interesting.

[Jackpine]

Originally Posted by BlackSTX

I'd hate to imagine what the oil temps looks like, I never looked, but will have to when I get mine back.
Also, I didn't realize the ECT was actually inferred.... interesting.

Yes, the whole ECT thing IS interesting, since we used to have coolant temperature probes into the coolant system (I remember having to replace one once when my engine overheated, ruining it).

But, they had a kind of "fatal" flaw. If the coolant went too low or boiled to the extent they were no longer immersed in liquid, they'd transmit nonsense values. The CHT temperature probe doesn't have these problems, since it simply warms up with the metal in the heads and sends (or passes) a voltage that can be interpreted as temperature. Since the coolant temperature has a clear relationship to the CHT, one can be inferred from the other.

I honestly don't know why we don't just see CHT on the dash gauge and be happy, except that years of the other reading are too hard to let go of.

The ECT dash gauge is really pretty poor in my opinion. About all it's good for is the "warning" that makes it swing to full hot when your engine is going into "limp home mode". It sure does not give you much "incremental" information on temperature changes.

The oil temperature is volatile as hell. I've seen it in the 245 degree range at high RPMs. And, I know from previous experience in an old Mercury, that it has a cooling effect on the engine too. If you let the oil get low, the engine will run hot. In that vehicle, the first symptom of low oil (it was on a long trip from Florida to Arizona when I was reassigned) was a gradually increasing coolant temperature. (I should have been more careful about checking the oil at each fillup).

- Jack

[BlackSTX]

Jack, I have to agree, the ECT gauges are very inefficient. They are not really a true gauge anymore at all, merely a visual toy that amounts to an equivalent of an idiot light. As one of the techs had commented, as long as it remains in a specified operating range, it usually just reads at one set position on the gauge. I suspect this was mostly done since many people today are highly incompetent when it comes to mechanical items and would be returning to the dealership every other day concerned about what the gauges were reading.

Jaguar went to this type of gauge too. They even updated they old gauge in some models to this newer type of system. If you needed to replace your sending unit, the "new" updated part now came as a kit that included a small harness which contained a resistor which then made the old gauge work more like the gauges in newer vehicles.

Unfortunately, I'm think they use a similar type of gauge for oil pressure readings too. I recall how my old Pontiac Sunbird had real gauges that you could see any and all fluctuations in pressure, voltage, and temperature, no matter how small they might be.

[06KingRanch]

Here are the max's i've seen while towing.

ECT 234
CHT 250
EOT 287
TFT 229
IAT 162

I've since installed a Troyer trans cooler, and now my max TFT was 202 on my last trip....and it is usually in the 175 range.

Running all Amsoil oils.

[Jackpine]

Wow! You WERE running hot. The transmission fluid temp was causing fairly rapid breakdown of the fluid. Good call putting in the new cooler. Did you have any kind of a transmission cooler before?

Also, you were only 8 degrees below the Failsafe Mode temperature on your CHT. This may relate to your recent post in the other thread.

How much weight are you towing? What engine do you have and what is your gear ratio?

- Jack

[408F150]

I hit 235 on my TFT gauge towing my toy hauler (was dry and weighed around 6500#) home from LA when I first bought it. This was going up the grapevine in southern cali in 95* heat with 3.73s on 35" tires. I've since upgraded to 4.56s and haven't seen it go about 208 (and now when I tow it's loaded and closer to 8000#) . I purchased a Troyer trans cooler but I'm having a hard time figuring out how to mount and plumb it I'm sure it will help even more

I have the Troyer dual e-fan and they have kept my ECT to 208 max, so they seem to help a LOT when towing. If anyone is having engine temp problems I highly recommend them or a similar setup. The wiring is daunting which is the only downside to them. I build custom in-home movie theaters and it even gave me a few head scratching moments.

Also, if you're running a constant 200* TFT, that seems a little on the high side. Even with just my stock cooler I'm usually between 165 and 180 during average interstate towing.

[06KingRanch]

Originally Posted by JackandJanet

Wow! You WERE running hot. The transmission fluid temp was causing fairly rapid breakdown of the fluid. Good call putting in the new cooler. Did you have any kind of a transmission cooler before?

Also, you were only 8 degrees below the Failsafe Mode temperature on your CHT. This may relate to your recent post in the other thread.

How much weight are you towing? What engine do you have and what is your gear ratio?

- Jack

Trailer is about 7000 lbs
5.4 with 3.73 rear end
It has the stock tow package, so yes it has the stock cooler. I hooked the Troyer into the return line, so i still have the stock cooler as well.
And yes i was hot...only did one trip and ordered and installed the Troyer and changed the eng, trans, rear diff, and washed out the rad....all good now

[hayjayhorses]

In my 2000 F550 7.3, 4r100, 4.88, 4" turbo back gross, stock fuel no chip, gross weight about 40,000 pounds. My gauges have a high temp recall feature.

I have a temp probe in the thermostat housing. On a hot summer day pushing a big hill it will get to 218, with the stock exhaust I got it to 225. on the flat it will stay about 190 (my foot is still in it).

I had a temp probe in the oil cooler port, under a load the oil would run a consitant 20 deggres hotter then coolant. I Have recalled that temp at 240 once.

I have 2 tranny temp probes one in the pressure port (tranny case) and the other in the line comming out of the tranny with my new tranny (Billet multi disk, shift kit, Long tru cool max tranny cooler) in last 15k miles the highest case temp I have seen is 195 and the ECT was at 215 on a 4 mile hill fully loaded, generaly the case temp will run 140 with an empty trailer (17,200# gross) and about 150-160 loaded. The temp comming out of the tourque converter will get to to 200 in town with a hevy load but cools right down to the same temp as the case shortly after the converter is locked up.

I also have a fan on my tranny cooler that turns on @ 160 case temp or by a swith, I turn it on in town with a load, it works very well. I mounted the tranny cooler (long LPD4739) in front of the ac condenser, and an electric fan is mounted in front of the cooler I cut out some of the grill, I will post some pics later.

With the stock tranny and cooler I could easly get the case temp to 220and line temp to 240 and it would take a long time to get to under 200.