Too Cool Ranger 4.0 Engine.......................

[dpfurby]

Last summer was extremely hot, normal 15 mile trips to and from work, so I added an additional automatic transmission cooler next to the factory cooler. It helped some, not sure exactly how much. It did not hurt anything. I don't want to kill the second A4LD transmission. I know heat will hurt any transmission. Mileage around 15 mpg.

Then came winter...........zero and below temperatures, normal 15 mile trips to and from work, the engine had a hard time warming up-- gauge was on the very low side of normal, coolant full, new radiator pressure cap, water pump, hoses, new thermostat, mileage dropped to 11 mpg (without using the 4wd).

Would the coolers be also overcooling the engine???
I could put manual valves on the lines to divert the transmission oil between one or both coolers-- winter/ summer or maybe I need to add a louvered door in front of the radiator-- to manually open or close-- winter/ summer???

Any ideas or comments??? thanks.

 

[RonD]

Blocking off air flow thru the rad is done not for the rad but to limit air flow in the engine compartment.

A Ford 192degF thermostat would prevent coolant from flowing thru the rad until engine temp is 192degF, just below 1/2 on the temp gauge, so rad shouldn't even get warm in winter months.
Since your temp is not getting that high, either you were given the wrong t-stat(160 or 180degF), feel upper rad hose, if it is getting warm then t-stat is the issue, new or not.
Or air flow in engine compartment is bleeding heat from engine too fast.
With engine off, spin the fan it should spin free, then after running engine for 10-20 minutes repeat that test, if rad is still cold fan should still spin free, if fan is not spinning free in either case then fan clutch may be frozen ON, and that can over cool engine in winter months

Blocking air flow is what many do in the winter, so worth a try.
Some switch to electric fans to eliminate any air circulation from fan in winter, and get extra cooling in summer.

You can also put pipe insulation on the heater hoses, these can bleed alot of heat in really cold temps, won't effect anything in the summer.
On the '94 Ranger the heater hoses are always circulating coolant, even with heat off, the heater core is the bypass for cooling system.
The heat control just opens and closes the Blend door.

And just as a heads up, if temp gauge ever goes up and down randomly the heater core is getting clogged up, good news is, it is easy to change, 4 screws and 2 hose clamps, and a new core is about $25.