Gary913

I have a 1995 mustang GT 5.0L. I just bought this car as a project, the previous owner told me it was over heating the last time he drove it.
It has a port for OBD2 but I couldn't get my scan tool to communicate(autel maxisys scan tool).
​​​​​​ I also have a older snapon scan tool and was able to get live data to work using the port on passenger side under hood.
Any how I noticed the fan wasn't kicking on.
when the temp gauge started going past the half way mark i was just shutting the engine off.
I was under hood with the scan tool and was watching the temp with live data and wasn't paying any attention to the gauge on the dash.
According to the scan tool, right when it hit 210 the fan came on and back off at 199.
All that seemed right to me but when I went back to watch the gauge on the dash it was going up past the half mark about 3/4 of the way up.
then the fan would come on and put it back to the half way mark.
I don't know if the guage is reading right and that's how it is soppsupd to be? Or is the fan coming on way late?
​​​​​​ My next step is I have a aftermarket gauge I'm going to hook it up and see what it says. I would like to keep the factory gauges
​​​​​​​​​​​​​Any advice would be great fully appreciated. Thanks in advance

Buck Sergeant

Gary913, on my carbureted engines I favor a 180 thermostat. My fuel injected engines seem to like it a bit hotter. I would check out the temperature gauge. 210 isn't bad with a fuel injected engine and 199 isn't a bad "kick in" temperature. P.S. is this a mechanical fan or electric?

Gary913

Thanks for your input I appreciate.
It is a electric fan
I haven't mest with the thermostat yet cause it looked to be circulating pretty good.

SmokyBC

imp

I bought my '94 GT over a year ago, in May. Into the summer here, daily temps often top 110 degrees. My gauge swung widely from fan turn-on to turn-off. This displeased me, a lot, when I considered how stable the temp. stays in my '04 Explorer with factory original fan and clutch, 165k on the car. Gauge remains rock-steady no matter the driving conditions, even prolonged idling with A/C on.

So I looked into getting rid of the electric fan. Look at the space between your radiator and the front of the engine. You'll see complicated brackets securing the over-flow catch bottle, which is ridiculously tall, and the ABS Module. Tempting project, so I started removing things. Got the ABS mounted on RH fender apron above the TFI Module. Yanked out the fan and coolant bottle; they looked like this:



Here's the new fan installed before shrouding it.

Urambo Tauro

I don't have much experience with those scan tools, but it seems to me that they could only read what the car tells it, right? I think you should use a thermometer/pyrometer to confirm actual temperatures when diagnosing.

On a related note, you "noticed the fan wasn't kicking on", but the scan tool is telling you it did turn on? Isn't the scan tool just reporting that the PCM was calling for the fan to turn on, when it believed coolant temp to have reached 210?

FWIW, the part about the fan finally kicking on when the gauge reaches the 3/4 hot mark sounds suspiciously like the low fan speed is not engaging, in my opinion. My '95 was doing that just a few months ago.

Buck Sergeant

Gary 913, all the responses are right on the money. As a added note, don't forget that your water pump is "reverse rotation." I had a customer come to me with a 1987 foxbody with a 331 stroker I had modified. He invested a ton of money into the cooling system but after running a while it would violently overheat. After checking the timing and all the "usual suspects" I realized we had indeed installed a "reverse rotation" water pump. After installing a new OEM fan ,same results, single electric fan,same results, and double electric fans,same results, I then, out of desperation, dug out a old "flex fan", "Reverse Rotation," and the engine sat at 180 under all conditions. The flex fan is still in the car. P.S. my rule of thumb is I never install any type fan that does not draw at least 2500 cfm. Most fans on the market are not able to meet this standard. Check with any aftermarket vendors for their fans cfm rating before spending your hard earned money. Remember, reverse rotation water pump, reverse rotation fan. This combination makes life much easier.

imp

Good points, all. Surprised you didn't spot that right away, when the fan was pushing underhood air out through the radiator! CFM of fans I've rarely run into, since I guess the volume moved depends so much on rpm. I recall Ford always printed water pump facts in Shop Manuals such as "15 gallons per minute at 2200 rpm (at the fan or crank??) dunno. Pump pulleys are rarely the same diameter as the crank, sometimes actually smaller, to get enough flow at low eng. rpms to "get by". Costs HP, though.

Then, there's the newer concept: Electric water pumps.......

Gary913

That would be my best bet to just do a way with the electric fan. It's just a ticking time bomb and the way you have yours it's going to last a long time.
Very good job A++

Gary913

​​​​​​Ya I agree, if they would have put number on the OE gauge then no worries. Like you said that "middle zone" is the normal indication for HEY DON'T GO PAST THIS MARK. It still drive me crazy cause I tested the guage it was working like it should.
Also put new temp sending unit that didn't make any difference. With this car being performance model, and it's a convertible.
Could it be that it's supost to run cooler. 170-180 range. FYI I do have a pretty good aftermarket gauge. I was thanking about just mounting it in the engine bay if nothing else.... Any how thanks for your advise