94 Ranger Cooling/Heating Issues Plz Help

[fastpitchfan]

Here’s a hard one. I have a 94 Ranger Super Cab, 5-speed, with a 4.0L engine, 120k miles. Up until two weeks ago, temp gauge always sat below the left side of the normal range. The heater/defroster was lukewarm, at best, but I thought that was normal.
Two weeks ago, I noticed the temp gauge was between the N/O and randomly would slowly rise to between the A/L, stop momentarily, then drop to N/O. During this time, the heater got warmer, so I assumed the coolant temp was higher. Here’s what happened next.

1. Took it to the shop and the thermostat was replaced and coolant flushed. Picked it up and on the way home, the gauge did the same thing and heater was warmer than normal.
2. Took it back and was told the radiator was clogged. Radiator, top/bottom hoses and thermostat (again) were replaced. Picked it up and gauge did the same thing and heater still got warmer than normal.
3. I checked online and found posts that mentioned a faulty temp sending unit. Went to dealer, bought a new temp sending unit and installed it myself. Gauge did the same thing and heater still got warmer than normal.
4. Had a friend look at it and he noticed the fan was cracked in several places between the blades where it mounts to the metal part. Took it to the shop and asked to have the fan replaced. Was told I should replace the fan clutch at the same time. I asked them to install an aftermarket temp gauge I bought at Advance Auto, while it was in the shop.

Here’s where it stands now. The standard dash temp gauge is disconnected. The new temp gauge reads about 120 degrees. The heater is back to blowing lukewarm air and that’s after driving at highway speed for 20 – 30 minutes. Here’s my questions:
Is a new fan and fan clutch all I needed? Is 120 degrees a normal operating temperature? Can I do something to get warmer air back without running in a hotter temp range? Or, should I just be happy with a cooler running engine, a new temp gauge and lukewarm heater/defroster?

[wvcat]

120 degees is not right. That means the thermostat shouldn't even be open. Your truck should be running in the 195-210 degree range depending on the thermostat they installed. I have to wonder if thay actually even changed it. If so maybe its a bad "new" thermostat. I would try changing it again. You can test one by putting it in a pan on the stove and seeing what temperature it is opening at. Of course you need a thermometer.

[ati190]

There's a little problem here. Your ranger needs to run at 195 degrees. It shouldn't take it 30 mins to reach 120 degrees, by that time you should be at normal operating tempature. I'm wondering if your tempature guage that you purchased is operating correctly. Is it a mechanical, or electrical guage? Can we see a link to it? Or just a model number will be fine. If it was running at 120F, I doubt you'd get any warm air from it. Even if your thermostat was stuck open, after 30 mins of highway driving speeds it would still be running hotter than 120F. As for the cracked fan, even if it wasn't running, that would make you run a higher tempature than 120. By your ranger not reaching normal operating temp, your truck is most likely running rich, and getting worse mileage than you should be getting.

[fastpitchfan]

The gauge is a Sun Pro Model CP8217. I noticed it runs closer to 140 degrees and only reaches 160 when it's shut off. If I start it back up, it goes down to 140 degrees quickly.
I thought it should hit 195 because the thermostat is 195, but figured it might be a stupid question. Does it mean the theromostat is stuck open?

[ati190]

Sounds like so. Pull the thermostat, place it in a pot of water, and heat it up on the stove. Use a thermometer to check the tempature of the water, watch for it to open or close. If it is stuck open you shouldn't see it do anything. You could have purchased a bad new thermostat. The thermostat shouldn't be stuck closed, if it were you'd overheat. It could have been installed incorrectly as well. When you pull it make sure the spring side of the thermostat is facing into the motor.

[fastpitchfan]

Hey, thanks for the reply. Now another question...For almost as long as I've owned this truck, the dash temp gauge always stayed on the far left, staying just outside of the normal range. My 06 Expedition gauge is almost always just to the left of halfway. Once it's started, it usually never moves.
Before my Ranger went in the shop the last time, the heater was getting hot, with the same thermostat. After getting the new fan and fan clutch installed is when it started running cooler again. Would the fan have any effect on the thermostat?
I hate to sound stupid, but if i replace the thermostat again, it will be the third one in less than 2 1/2 weeks.
Do you think I should try a new shop? To date, for this problem, I have spent almost $800 and he'd probably love to keep taking my money! The thermostat is in a difficult place to get to or I'd do it myself.
Also, is it possible that two thermostats could be bad?

[ati190]

Another curious question, are you running the OEM radiator? Now, for the thermostat, like I said, I wouldn't purchase anymore parts till you diagnose the problem. Drain the coolant (easy), Follow the upper radiator hose into the thermostat housing, remove the bolts, remove the thermostat housing cover. You may need to use a rubber mallet or something to loosen the seal. Pull the thermostat, and test it in a pot of hot water, see if it's opening or closing at what degree. Your mechanic might have thrown in different thermostat, i.e 160 degree one or something. The fan would make it run slightly cooler, however if the any of the fins on the fan weren't broken off, I'd find it hard to believe it would make that much of a difference. The truck should still reach operating tempature after 20 mins highway driving. I think the thermostat is where your problem is. It's not a complicated job at all. Make sure it was installed correctly, air release valve up, and spring side facing into the motor.

and here is some step by step instructions for you!
http://www.therangerstation.com/tech...Thermostat.htm

[ati190]

Defiantely wouldn't take it back to that mechanic, he's just guessing at what could be wrong. He's just using your money in hopes of the problem going away.

[BlackBII]

Originally Posted by fastpitchfan

After getting the new fan and fan clutch installed is when it started running cooler again. Would the fan have any effect on the thermostat?

Fan affecting the thermostat itself? No, but the fan will help the engine run cooler. New fan clutch? You should be able to stop it with your finger or a peice of cardboard with the engine idling, if not, then the clutch could be 'stuck', and cooling your engine more than it is supposed to.

Your truck is a 94 right?

I suggest getting a real temperature gauge, rather than relying on the stock gauge and how far to the left it is. You need to find out how hott the coolant is getting, in degrees, not by Ford's 'Normal' calculations, as they are not always correct.

What degree thermostat did you get?
Are the heater hoses getting hott after driving awhile? How long can you hold your hand one them?

And it's not the thermostat that is going to control your gauge per say, it's going to be the sending unit and the gauge itself. That's why you need to find out what temperature your coolant is getting up to, to see what is at fault, the thermostat, or the gauge.

[warment]

My brother has a 93 Ranger that does the same thing (temperature stays on the far left side of the "normal" area). I recently replaced the thermostat with a new Motorcraft unit. The gauge now seems to read a little than higher, but nowhere near the center of the "normal" area.

[calypso93]

I took some readings on my 4L 93, using a contact thermocouple and an IR non-contact thermometer. I did it because I wasn't sure what my dash gauge was telling me. It reads from "N" to "O" all the time. The instruments showed from 180F to 210F, off the t'stat housing nipple, close to the upper radiator hose. I believe the last t'stat I put in was 195. Guess the dash gauges are all over the place and not too linear.