I added additional thermocouples and have the Omega data logger to record the data, one nice feature is the data is real time stamped. There are now 8 thermocouples. There is an indoor/outdoor thermometer used for measuring the temperature of the air entering the grill.
1. Trans out, start of the steel feed line.
2. Rad-ATF cooler inlet, also the end of the steel feed line.
3. Rad-ATF cooler outlet, also the Air-ATF cooler inlet.
4. Air-ATF cooler outlet, also the inlet to the steel return line.
5. Return inlet, beginning of the steel return line.
6. Trans in 1, about 6 inches in front of the return line fitting.
7. Trans in, end of the steel return line.
8. Ambient front, engine bay at the front of the steel ATF lines.
9. Ambient mid, engine bay at middle by steel lines.
10. Ambient back, about 6 inches by the steel line fittings on trans.
11. Inlet to engine thermostat housing, feed from the lower radiator header where the Rad-ATF cooler is located. TC between the lower radiator hose and housing nipple.
12. ATF pan, ATF temperature measured in pan through dipstick tube.
The logger is only four channels so not every one can be recorded. The first time I did a cold start log with the trans out, rad-atf inlet, air-atf outlet, and trans in TCs. This was to get some feeling for the temperature change in the line during heating and hot-operation. The ambient temperature was about 85F for the short drive of about 9 minutes on city streets at about 40 mph. Nothing unusual was observed, the atf heated with temperature peaks from sitting at lights and slower heating with easy driving. The difference between the rad-atf inlet and air-atf outlet is the sum of the temperature difference for both coolers so no conclusion could be drawn about the radiator coolant heating the atf fluid from this log. It appears the there is more heating in the return line than cooling in the feed line as the engine and transmission heat up. A possible conclusion is there isnít much transfer between the two lines.
A second log was made when hot at speeds of about 40 mph with the ambient temperature 95F to 99F. The peaks and valleys correspond to sitting at lights and steady driving. The heat loss in the feed line is much lower than the heat gain in the return line. The engine bay ambient temperatures havenít been measured yet.
Next day log used the thermostat housing or rad coolant, rad-atf in, rad-atf out, and air-atf out TCs. Cold start at about 35 mph.. The temperature of the thermostat housing increased rapidly until the thermostat opened and the coolant started to flow into the housing with the observable temperature drop. Given the thickness of the casting I would expect this temperature measurement to be the least reliable, though it is probably higher than the coolant temperature. From the start the temperature drop in the rad-atf cooler was measurable, no evidence of any heating. Given the low speed and the low atf temperature there wasnít much cooling in the air-atf cooler.
The next log was about two hours after the end of the previous log with the shut off. The log was divided into two consecutive plots. Ambient temperature was 95F to 99F. The first plot was at driving speeds of 35 - 40mph. The thermostat was closed at the start and then opened and behaved predictably. As the atf heated both coolers became more effective. The rad-atf cooler had a larger temperature drop than the air-atf cooler, especially at lower vehicle speeds.
The second part of the log was at higher speeds of 50 - 60 mph on level to slight downhill grades. The rad- atf cooler was still more effective than the air-atf. Up to the higher speed the converter was probably not locked very much because the traffic conditions. The temperature drop in both the atf and the coolant was dramatic. The reduced cooling from the air-atf cooler at lower speeds is very reproducible and expected.
There was one more log of hot start and a few short trips with brief engine off periods, 96F - 99F ambient and speeds of 35 - 40mph. The logger was left on during the engine off periods. Nothing surprising but interesting how quickly the temperature at the housing drops when coolant starts to flow.
Iím planning on doing similar logs on our upcoming trip to Ouray in a few weeks with off road trips planned. The temperatures should be lower. I also have a trip planned to Page, AZ, in mid August when temperatures should be in the 90s. More data to come.