overheating/ radiator fan inop

[mightymoose_22]

I have noticed there have been many posts about the radiator fan not working right, and I had the same problem with my own 94 Escort until I finally put a switch on it.

Several people describe the same symtoms... low speed fan does not kick in and causes the engine to run hot until the high speed eventually kicks in at the end of the temp range.

We know the fan motor is good since it eventually comes on... in my own case and a couple others the coolant temp sensor was replaced with no change... fan works operates at high and low speed with the code reader, so relays are good.... On mine I even swapped the PCM with no results.

Fan motor, sensor, relays, PCM... all good. Why aren't our fans working right? What else is in the circuit? I wonder if our cars are old enough that the same part is crapping out at the same time.

The only thing that kept my car from overheating was the air flow from driving. My AC is busted so I can't switch it on to run the high speed when I want it... so adding a switch was a quick fix. I'd still like to get it to work right though.

Can we brainstorm a solution here... seems like it would be beneficial to many.

My most recent thought is that it may not necessarily be electrical... perhaps there is a circulation problem and the sensor isn't reading accurately? I dunno... it got to be a headache, but I think I am ready to tinker with it again.

[Arnoldtheskier]

Mightymoose..ALL good points!..

I don't know offhand the exact mechanism for low speed operation.Is it simply a voltage drop?I guess a remote volt meter could be hooked up and watched.

"Overheating"..I think that we need some criterion/parameters for that.LOL..there is not really much "overheating" done with these motors!.They DO NOT like..or tolerate overheating.Not something that is done and gotten away with..sure maybe a LITTLE bit.Seems to me those that have "gotten away" with overheating have more serious problems(valve seats) not long after.

These are cool running motors..efficent.

In my case..93..I don't need no stinkin' fan or relays or sensors from about Oct to May..below 60 deg..the dash temperature gauge ain't gonna hit the centre of the normal range.Stays to the left of that.At -35 with howling winds,blowing snow..the gauge just hits the beginning of the n in normal.Ya gotta run the heater a lot to keep barely enough heat in this wagon.Above that temperature it is ok.

The high and low speed fan in my car works ONLY with the code reader too.
The high speed fan comes on when the coolant reaches about 220 degrees. not hot..OR intolerable for one of these motors.I base this 220 on the fact that I have an S/W mech temperature gauge mounted iside the car that I watch.The sender for this gauge is about 1' past the factory sensor in the heater hose circuit towards the heater core.Iam guessing about a 10deg loss there SOooo..when this gauge hits just over 210..the fan comes on..that is why I figured (from past experience) this was about 220 actual degrees.This corresponds to the factort gauge JUST at the end of the normal range.This is not overheating..and the car has lived to 270,000..runs like new.NO oil leaks,burning,bad noises.
I need 75/80 degrees high humidity..zero wind and some serious traffic/stop/go to get the car this hot.ONCE it is moving..gauge goes right back.

Do I need a low speed fan in my car? Me thinks not.IF I want to cool the engine a bit earlier..I just hit the a/c button.

Even at 210 degrees gauge/220 actual..these little motors do not seem to be prone to "heat soak".I have shut mine off numerous times at this temperature..and the always on mechanical gauge..even the factory gauge..sitting there with the ignition on..show very little temperature rise.Yikes..some motors..shut them off..and the heat SOARS and either on comes that fan or toast goes the motor.This motor doesn't even seem to get hot enough to make that "tinkiling"/crackling sound after it is shut off.

In any case..IF you needed the fan to come on earlier..low or high speed..and you didn't want to fiddle with switches..if you can't get this to work the way it is suppossed to..then..as I mounted a sender in the heater hose..shouldn't be hard to find some other type of sender to mount..to turn the fan on/off for you.There are a TON of aftermarket electric fans/senders out there.ANY hot rod book/magazine will have this.

[mightymoose_22]

Overheating... well I guess I don't quite know if it is technically overheating... but what happens is that it runs all the way to the end of the indicated normal range before it ever comes on, so it is running much hotter than it used to. It used to stay between the O and the R on the scale, which I would guess to be around 180 degrees since it is a 180 thermostat.
This is a new engine in this car... I replaced the old engine because the valve seats broke up and caused a majot mess... so I hope to get this resolved before the same thing happens with my new engine. I had not noticed this temp issue before replacing the engine, but it may have been there.
I hadn't really thought much about rewiring the fan with an aftermarket sensor... suppose I could... but my preference is to get it working right... the way it was for the last 10 years. It's just a dang fan... shouldn't be so complicated.
A lot of people have this issue though... I can't figure out what the heck is wrong.
The wiring diagram in my Hatnes book shows the EEC module connecting to the relays... which to my knowledge is the PCM (the computer under the center dash). I wonder if there is a different computer I should look at... I honestly am not certain what the one under the seat is... and I have been suspect of the EDIS for awhile... aarrgh... just frustrating.

[mightymoose_22]

A little investigating yesterday:

The ECT seems to work right... It has more resistance across the switch when cooler and much less when hotter.

The power at the switch (I think it was a blue/w wire) had just under 4 volts. I have no idea yet if that is in spec or not.

I traced the wires through to the computer and both were good.

I fixed my A/C yesterday... when the A/C is on the fan operates as it is supposed to.

Again, a test with a code reader and the fan worked at high and low speed.

SO... ETC is good... wiring from ETC to computer is good... about 3.8 volts at ETC... high and low speed fan relays are good.... I previously swapped the computer with another with no change, so the computer is good....

For some reason the fan does not turn on at low speed... either the computer is not getting the signal for some reason, or the fan is not receiving the signal from the computer. Since the ETC appears to be good and wiring to the computer is good, and since the computer has been tested with another... well it seems that the problem is somewhere between the computer and the fan motor. I will have to trace it further, but I am not sure what else it passes through other than the relays.

At least my A/C is fixed... it was nice to have something go right for a change

[daleb9]

mightymoose_22, in regard to your comment "It's just a dang fan", that's OK, but there is a temperature sensor that provides info to the computer, and two relays also to be considered. Plus a lot of wires that might have intermittent shorts and/or opens.

When I got my '93 1.9 I think the problem had already developed, that was 2001. But my driving didn't aggravate the problem for a while, till I got stuck in a real hour long traffic jam, then the gauge read far right. I fussed with it for a month or two, finally found the relays under the air cleaner box, and decided to jumper that so the fan ran on low whenever the key was turned to run. That addressed the problem well enough and I let it go.

I did some long searching on Google Groups for "escort heater fan" and around the fiftieth page I saw a link to a message in which the writer declares the problem is in the ignition switch. I wasn't ready to spend $150 for a replacement when the jumper worked fine, so I didn't, then.

A few months later however, the darn ignition switch broke, the rod from the keylock cylinder to the switch itself snapped. Friendly local welders are few and far between, so I paid for a replacement at the dealer. It was kind of a messy job putting it in, they use bolts that are tapered right below the head, so the head breaks off when they're tight enough. To remove them you got to drill the old ones out. Messy.

So with the new switch in, after a few weeks I thought of the message, took the jumper off the relay circuit, and was pleased to find that the fan worked OK, it didn't come on when the motor first started up, but did after a few minutes. Curiously, the temp gauge showed almost the same thing as when the fan was always on low.

But after a month or two, I again noticed it was getting hotter, and found the fan wasn't coming on, I let it run at idle until the gauge was well over half way, fan didn't come on, nasty smells of crisping gasket cement. I shut it off and hooked up the jumper to the relays again.

This inclines me to consider the hypothesis about the ignition keyswitch plausible. Unfortunately, I am not inclined to tear out the ignition switch, which would be necessary to get test leads for a meter onto the connects. Possibly there is the trouble. I found that the new ignition keylock switch mechanism which detects whether the key is in the ignition or not became unreliable within a few months too.

My radio loses it's memory presets every time I turn the motor off, how 'bout yours?

[mightymoose_22]

I don't know about your radio problem... that is a new one to me. Off hand I would think it is a problem with the radio itself.

Thanks for your info though... I will look at some diagrams and see what the deal is with the ignition. I may get some jumper wires and go around the switch and see what happens.

Thanks