radiator fuel heater

Granted, I live in Phoenix, Az. where its currently, at 10:00 p.m., 101 degrees. I've always thought that having the auto trans. cooler built in to the radiator was a stupid idea, as if the engine overheats it cooks the auto tranny fluid, and most people don't think to change the auto tranny fluid after an overheat. I guess it might make sense for colder climates, but I have always bought a seperate auto tranny cooler. Now I know what to do with the one built into the radiaror.Jim

Radiator might handle 15 psi (not sure what ATF pressures would be)...but will it handle EFI fuel pressures?

The fuel pump creates the pressure in the injection system.

AFAIK the tranny cooler in the radiator can take some pretty massive pressure; it's all steel line. It won't actually put any pressure on the radiator itself, either. Just the steel line running through the radiator. :)

Keep in mind that the cooler/radiator is going to be much cooler than engine thermostat temp. Maybe like 130° for an engine temp of 195°? I don't know what the ideal fuel temp is so maybe that's perfect.

This is a truly clean idea - I like it for a manual-trans car! BUT! Use caution before bypassing the trans cooler in the radiator. :!: That type of cooler is a liquid-liquid cooler (uses the thermodynamic principle of [i]conduction[/i]), which is [u]significantly[/u] more effective at removing heat than the typical add-on air-liquid cooler (uses the thermodynamic principle of [i]convection[/i]). And as most of us have heard somewhere along the way, heat is the #1 killer of an automatic transmission. It would be a real shame to cook a trans to gain some MPG, and the situation will happen slowly enough that you might not make the association of the failure.

There are some judgments calls available, though: Got a small car, live in a cooler climate, and/or do mostly highway driving? If so, you could install a huge cooler (like for an RV) and probably be OK.

However: If you do any idling in traffic -- the torque converter is stalled and is making heat. Do a lot of city driving -- the converter's lockup clutch may not apply until 40 or so mph, and if not applied it is making heat.

Got a large car, a pickup truck, do any towing, etc - I'd avoid this idea altogether.

If you go to the efforts of installing temperature senders for the trans you could verify temps before and after the cooler modifications, but this would require a bit of plumbing work and $75 worth of gauge/sender parts. If the temps were too high after the bypass you've just 'wasted' the cost of the gauge, the cooler and your time.

I don't have any hard data to offer due to all the variables involved - but I just happen to work on the engineering side of automatic transmissions. Food for thought...

I want to try it on my '97 Ranger (5-speed manual) but I'll have to find a cheap radiator from an auto first.

I heated the fuel almost to coolant temp in my '99 F150 and it made no difference...