Woof

Ok, here's the short version:

I bought a 1996 Stang 3.8 V6. I got it from a friend who HAD been having cooling issues with it. Gauge routinely goes as high as "A" in normal, but stops there and never reaches red. Being a responsible owner she took it to a Ford dealership who replaced:
the thermostat
radiator - three times but once was because the mechanic screwed it up
hoses.
After $1200, they wrote on work order "try to drive on cool days." and gave up.
She then took it to an independent who continued to basically do the same things but it worked for a minute, long enough for me to buy it.
Current status:
Starts and runs like a champ. Temp gauge goes to "A" on warm days and is lower if its cold out.

1. Coolant is new.
2. Fan doesn't come on but does work, I jumped it. It may come on at higher indicated temps but I have been hesitant to let it got to "A" and test that theory. Black wire when testing for resistance is about 5 ohms.
3. I have hot water at top and bottom radiator hoses.
4. Coolant temperature sensor was 32 ohms when warm, which is high for the specs. I had already warmed it up so have not checked it cold.
5. PCM voltage was 4.6v

I don't have an OBDII, I could have them read it at Oreilly's/Schucks. At this point I'm sure which direction to go, Gauge? CCRM? And, where is the CCRM on this beast? One place in the manual says the engine compartment and another says behind the fender well??

Thanks

08'MustangDude

Fans should come on at just near or just above the half-way point.

There are relays that control the fan as well, and fuses. Low and Hi side relays.

I see everything was addressed except the electrical portion.

When you turn the A/C on, the fan should also turn on, and it will stay on
as long as the A/C is active. If you have no fan with the A/C on, then
there is a problem with the fan electrical circuit.

It will be cheaper to buy an aftermarket temperature sensor probe kit, with a relay, to
run the fan. These kits are on eBay, and they come with a slide in probe, that
will slide in between two fins in the radiator. You can set the temp range on a
small pot (variable resistor). This will control the fan.

Woof

The A/C is not functioning, just pumps hot air.
The low speed fan is controlled by the coolant temperature sending unit and the coolant temp sensor, both seem to be checking out ok.

I suppose I could just let it heat up and see what happens. All the way to "A" seems high but perhaps its the gauge?

pure_kaos

I had a similar issue with a 97 I used to have. I replaced both the coolant temp sensor and the gauge sensor. Temp never went more than between the "r" and the "m" afterwords. Just a suggestion if you haven't done that yet.

Urambo Tauro

When you tested fan operation, did you confirm that both low and high speeds work?

Which coolant sensor did you test for resistance? The ECT sensor that sends a signal to the PCM, or the sending unit that operates the dash gauge? These sensors produce different ranges of resistance. Also, how "warm" was the engine when you saw 32 ohms?

My '95 has the CCRM near the radiator fan, but IIRC 1996 might have been the first year that Ford moved it to the fender...

Woof

OK, here's a new update. I checked the high speed fan and it did come on. The car actually seemed to be running cooler today than ever before until I replaced the coolant temperature sensor, then it heated up just like before, hitting the "A". I think it's an air bubble at this point. I also changed the sending unit that goes to the gauge. Now I'm going to call it a day, let it cool, and burp it tomorrow. I'll let you all know the results.

Urambo Tauro

Ah, good call. I totally overlooked the part where you said "new coolant". You definitely want to rule out an air bubble first. (Fortunately, those V6s are easier to burp the air out, thanks to that bleeder on top.)

Woof

The Clymer manual says there is no bleed on the 3.8 motor. If you know different could you please point me in the right direction and tell me where it is?

Mikekasual

The coolant bleeder valve is bolt under the end hole of the cresent wrench. Hope this helps and sorry about the wrench but it couldn't hold the phone, point and take the pic.

Urambo Tauro

Yup, that's the one. IIRC, Ford used to put a little plastic ring around the bolt that said "remove before refilling" or something to that effect.