F-150 fan clutch issue: second act

Sounds like they never found the root cause...

Sure, they know the four first level flags telling the ECU to turn on the
fan, but do they know what the flow chart looks like for secondary and tertiary flags looks like?

That is in the logic diagram for the ECU, but the root cause can still be
in other areas of the thermal rejection system.

Like plugged to low flow of any of the liquids/lubes/etc to the coolers or
thermal exchanges

A good one suggested is that the TC isn't locking up and leaving the TC
in hydraulic slip, which is normally in the 15% range. Meaning that the
power input to the TC has a lost 15% due to hydraulic shearing inside the TC

Seems that they replaced or took out the TC...what was their report on that?

If me, any time a TC is taken out, replace with a complete rebuilt or new.
Min would be new friction material in it's clutch

I'd now suggest taking the main radiator out and have it boiled out or
flow checked. All three systems of it...assume it has an engine oil and
ATF section in addition to the engine coolant section...

and a BIG ETC...air flow to the various radiators?

smkettner wrote:
Can you tell if the torque converter is locked up?

Exactly.
Probably 75% of the heat comes from the TC when not locked up.
Maybe there is a bypass valve on the cooling line/trans that is stuck in bypass?

Engine coolant temperature
Trans oil temperature
Engine oil temperature
Air conditioning pressure

These are the four parameters. Your fan is most likely working correctly...

Can you tell if the torque converter is locked up?

According to tech, only one of four parameters that kick the fan on was trans fluid temp. When it hit the precribed temp of 240, the fan kicked on like it's supposed to. So, trans fluid temp is too high. The cure was supposed to be all the parts they changed. Now that it isn't, not sure what the next step is. I verified myself with my digital IR thermometer that the pan fluid temp is 220 today, so likely at least 240 wherever the sensor is located. Going to be fun to see what happens next. A lot of people looking at the floor while they speak to me, I'll wager.

it's a sign of a plugging oil cooler or the fan temp on is set to low in the computer

Did they replace the fan clutch? With engine hot you should hear the fan sucking air through the radiator. Probably 5 out of 6 don't work.

agesilaus wrote:
Mechanics and doctors are the two professions that don't stand behind their work. They get to guess and you pay hoping they are right. If they are wrong, they shrug and think of something else to try at your expense. I wonder if a small claims action would work?

Stay tuned, we may get to find out.

Mechanics and doctors are the two professions that don't stand behind their work. They get to guess and you pay hoping they are right. If they are wrong, they shrug and think of something else to try at your expense. I wonder if a small claims action would work?