I desperately need some input here. The 1994 ranger has significant sentimental attachment for us. At age 15 grandson worked summer job to purchase it for his Granddaddy. We have spent an enormous amount of money over the past 12 years attempting to bring it back to its original glory. It ran like a fine tuned sewing machine for the past 10 years. When it started using oil, we decided to replace original Mazda 4.0 engine (200,000 +/-) with a Ford 4.0. All work done by professional mechanics shop of 25 years experience. Since engine replacement the A/C quits work in idle or continuous slow traffic. We have replaced entire A/C system, changed radiator, installed a twin blade electric fan, replaced fan motor and mechanic has even replaced the 1st remanded engine with a 2nd one (the first one had a three year warranty) The mechanic thought the first one had stopped up “water jets”, thus the second engine. With all these efforts the A/C problem continues. Now the mechanic wants to pull out the electric fan and go back to standard style with a different “cup”. We are at our wits end and out of $$. If anyone can provide any suggestions to help guide us in this extremely difficult issue, it would be greatly appreciated. We are really beginning to have significant doubts about the mechanic’s competency.

 

A mechanic that wants to replace the engine (twice???) for an AC problem will not get my money.

Is your ac charged properly? Are the low/high switches functional? Oil? Did you replace the compressor with the engine? What exactly did you replace on the AC system?

"Water jets" means nothing to me. Perhaps it is a Ranger thing, I don't know.

 

There is NO difference between a Mazda 4.0 and a Ford 4.0
They are both based on the German design 2.8, first in the 74 Capri? Possibly earlier
No A/C works well at idle or in traffic
Every car or truck will start blowing warmer air at idle or in traffic
That said, they do still blow cold, just not AS cold
I think you should be using the stock fan which will flow more air than most electric fans and, YOU NEED the Fan Clutch
That fan clutch, when hot, locks up and flows more air (if it is working properly)
Mechanics generally do not bad mouth other techs, (because you're next)
I think I would have someone else give you a 2nd opinion

 

@Mcmillc1 why are you starting identical threads? Confusing.

https://www.ford-trucks.com/forums/1...ord-4-0-a.html

 

Sorry for causing any confusion. I am a new member and this is my first post. I discovered after initial post there was a more appropriate thread for my particular post. I tried to delete the fist post but was unable to do so.

 

Thanks for all the input, much appreciated. I’ve taken the advice and taken truck to a different shop. The consensus of their 4 mechanics is the new thermostat is not the right one. Currently has a190 degree and their recommendation is replace with a 180 which would allow the fan motor to kick in much sooner thus significantly improve air flow. The original shop said the 190 degree was necessary for fuel injection system to work properly. I have little to no mechanical knowledge or skills, thus dependent on the pros for all such needs. However, I do have a little common sense and the fuel injection interference sounds a little sketchy. Any thought /recommendations would be very helpful right now.

 

The original shop is right. 192/195 is the correct thermostat.

 

Are you sure they didn't say "switch"? The electric fans use a thermostatic switch to turn on the power to the fans. The switch would be installed somewhere in the cooling system flow area. A lower temperature switch would turn the fans on sooner.

If you use a lower temperature thermostat the fans will be less likely to turn on, not more.

But, if you didn't need the fans before you shouldn't need them now. It might be that the fans are actually blocking flow, not helping it. Are they from Amazon or eBay? There's a lot of aftermarket junk out there.

I think that of the four mechanics one probably guessed and the other three just agreed.

 

The electric fan that was installed on round one (installed by first mechanic shop) in an attempt to improve air flow was taken out and the original fan with a new fan clutch was reinstalled at the same time the new 190 thermostat was installed. We are dealing with newest remand engine (190 degree thermostat) with conventional fan, new fan motor clutch, new radiator and a complete new A/C system. All done to decrease moderate engine overheating and A/C drastically reduced (barely cools at all) at slow or idle speed. The recommendation for installing a new 180 degree thermostat, as explained by second group of mechanics, was the lower thermostat in engine would allow the water/coolant to circulate sooner thus keeping the engine cooler which would aide in reducing the overheating of the compressor. There consensus was the fan in place had more than enough air flow to keep the engine and compressor adequately cooled. I have no idea if their rationale is legit or not. My concern is if the 190 thermostat is accurate, what, if any problems could occur by installing the 180. I might add, we are located in NW Florida where we have fluctuations (high to mid range) temperatures in the summer.

 

What does "moderate engine overheating" mean? Does the radiator have a fan shroud? Does the overheating occur even with AC off?

If the engine is overheating with a 190 it will still overheat with a 180. The cooling system will be removing the same amount of heat.

Who built the engine?

Good luck. Overheating problems can be tough.

 

Moderate heat - in this case temp gauge at idle/low speed stays at approximately 1/4 past center. Drops back to center to slightly lower when open road.

Yes shroud is in place
Yes same conditions with or without A/C being on.

Have no idea on builder of remanded engine. The 1st repair shop that installed it did the ordering.

Thanks, I am definitely finding that out. The mind boggling thing is everything work perfectly until engine was replaced because of excessive oil usage. The original engine had a 180 thermostat and never had over heating problems or any other problems for over 10 years. With the new engine in place it seems we have had to have a pot full of other parts replaced without any success at resolving the initial problem of overheating/air flow issue.

 

@manicmechanic007 might have more thoughts since you've redefined the problem as a cooling problem and mentioned that the system has been converted back to stock as he suggested. Some Ford engines only do well with Motorcraft thermostats. I don't know about the 4.0.

 

So you don’t know if that is where the needle normally is for that sending unit or if the engine is actually overheating which it doesn’t sound like is actually too hot. . Has anyone checked it with a temperature gun?

 

The sending unit was replaced (2nd engine replacement) by the initial mechanic shop, as part of their diagnostic attempts to find the overheating problem and yes they did check it with temperature gun. They did not reveal what the actual temperature was to us. However they did share that the temperature/air flow issue caused the new compressor to pop the safety valve. They replaced sending unit and checked the refrigerant levels in the new compressor as well as topped off the refrigerant to the specified levels. With all that, I am very confident the engine is in fact running too hot, not in the excessively high range but definitely enough to be problematic, enough so when the combination of excessive engine heat and deficient air flow is enough to cause the second newly replaced compressor. We have already had to replace all components of the A/C system because the compressor came apart and distributed debris through the entire system. We are just trying to find a fix for the overheating engine and compressor so we don’t have to go down that road again financially.

 

Through this journey and talking through the overheating problem with a multitude of contact a friend of a friend of a friend had a contact the was a Ford Engineer. Once provided with serial number of engine, he identified the Ford part number of the fan that was needed. Original mechanic shop ordered the fan and installed it. Also replaced thermostat, spark plugs, oil change with new filter. Have put 100 +/- miles both open road and idle/low speeds and temp gauge stays on the cool side of center and A/C just super cold on open road and very cold at idle tests. Our temp here in Nw Florida has been 85-88 degrees. Early days, but I think they have finally solved the overheating/air flow problem.

Thanks for all the responses in this forum.