Low speed cooling fan on/off points too high

[zak]

Of course this acts up the week before the convention.

OK, so my 95 MTX was having some cooling issues. Had a hose that didn't get tightened down on water pump replacement, and my cap was only holding 12 psi instead of the 15 or 16 psi rating. Figured I had it nailed when I replaced the cap with a new, tested Ford cap, and tightened up the hose.

Car has been fine the last few weeks, but driven on max AC because of the heat wave (fan goes to high on this setting and stays there IIRC). Today it was less than 80 and low humidity, so I drove on vent the whole way home. One bout of stop and go traffic.

Get into my town and the needle is up to N in NORMAL, and the engine is running a little rough. Pull over and the fan kicks on as I open the hood (on low), The fan runs for a minute or so and then kicks off, with the needle barely down below O. Drove it home trying to keep airflow over the radiator, and in the driveway the same behavior.

This is way higher than historic levels (I am the original owner) - usually I get fan on at the M and fan off at the A. Is this a CCRM relay problem? If so I can not read the code as my module has a thick black cushion of some kind adhered onto it from the factory. Is there a specific coolant temp sensor that EEC looks at to decide fan on/off? The one next to the T stat?

Or is it the close proximity of the fan motor to the exhaust manifold as a consequence of the two row rad, plus subframe slid forward?

Any insights gratefully appreciated.

 

[itwonder]

Sounds like a non-issue to me.

 

[zak]

Bob, it could be - especially if the gauge calibration has drifted with age.

However, when it gets that hot the engine runs rough, losses power and will even stall.

It is fine on max AC . . . . .

 

[shopartsnw]

94-95 MTX used a D code CCRM. As far as I know, the D code was only used on this car, and will not work with any F6 Taurus part.

Here are a couple things to check.

Pull the codes on the car. When you start pulling the codes, it will cycle the fuel pump and then run the fan on low and high speed. If the fan does not run on high speed, this could be your problem. Most likely at this point it would be your CCRM module, but I guess it could be the fan or wiring.

The EEC temp sensor is the larger sensor that screws into the lower drivers side of the thermostat housing casting. If this sensor went bad, the car would not know how hot it is, even though the gauge says it is hot. The gauge sensor is the single wire sensor; the EEC sensor has a plastic connector with two or three pins IIRC. It can be changed without pulling the intake (deep well 7/8" or 1" I think), and you will only lose a small amount of coolant if you are quick.

We have new and used D code CCRMS on the shelf and ready to send (along with gauge sensors too) if you need anything.

Let us know.

Mike

 

[rubydist]

check your ground strap from the engine to the firewall near the pcm. my experience with sudden changes in temp gauge readings is that they can be caused by a poor ground between the engine and the firewall.

 

[SHOZ123]

The high speed fan only comes on with the AC on the older SHOs IIRC