I live at the bottom of the Texas panhandle, so we get the best of both worlds - dry, hot summers, and humid, cold winters - not as cold as up north, mind you, but we do dip down into sub-zeros every year.

On to the point, with my wife's 91 4.0, when running the A/C, the engine begins to heat up beyond normal range when moving, and climbs high and fast when sitting, idling (like at a traffic light, drive-thru, etc.) Of course, as the engine temps go up, the A/C blows warmer air - not hot, but not as cool as it was. This is made worse when she tries to use the rear A/C for the kids.

This only started about 2 months ago. This is the second summer we've had the van, and the first time it's ever done this.

The heating up eased a little when I changed the plugs and wires 2 weeks ago. It still does it badly when idling, though. And only when it's really hot outside (ie, when you need the A/C the most!) There is no load on the van at all - no heavy cargo, nothing...just the family...

Mine and my dad's first thoughts were possibly the fan clutch is starting to go out, not allowing the fan to turn fast enough at idle. In this case, I was planning to install a flex-fan and space to replace the fan clutch and plastic fan. A cheaper, albeit slightly noisier, alternative to an electric fan setup.

Any other ideas?

 

Sounds like a bad clutch on the fan. Also make sure the radiator and ac condensor are clean (lots of bugs and stuff can get between the radiator and condensor. If you go to the electric fan option, .let me know how it works. Good luck.

 

I agree, sounds like a fan clutch. I replaced mine on my 90 4.0, replaced just the cluch and used the old plastic fan, cost was about $20, it been a little while back.

 

If I go thr flex-fan route, does anyone know which spacer I need?

 

I agree with the fan clutch.


I would also check the status of the water pump and maybe decarbon the engine (when it gets all gummed up it will create more heat.) Do a search for seafoam.

 

yeah, this is my plans...

remove the radiator, and flush it out real well, clean and straighten any bent fins..replace the rad hoses, the drive belt, the thermostat, either a new fan clutch or a flex fan (if i can find a spacer for it...), and seafoam the old beast....

Then, hopefully, for ext tax return, i'll rebuild the front end (control arm bushings are shot, upper and lower ball joints, sway bar bushings, etc...)

Get the tranny serviced out, and install a nice big aux cooler....

 

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A flex-fan and a fan clutch are two different parts. I know you probably knew that, but the fan clutch (like the guys are telling you) is what you want. Good luck...

 

A flex fan and spacer would be a good middle-ground, inexpensive upgrade alternative to an electric unit, if I could locate the proper spacer.

Every car I've ever owned with an engine driven fan (except my aero*), I have swapped in a flex fan...they work better than the fan clutch / cheap plastic fan combo, in my opinion, and from my dad's 45+ years of experience with them...

 

Flex Fans were an improvement over the heavy, steel fans from years ago. There is a reason why all domestic auto companies went to a fan clutch fan. These fans shut off, at freeway speeds, when fan cooling is not needed. It is not really "cheap plastic" per se, only plastic is used because it is light and saves weight. Also, if there was a real benefit for a flex fan, which would benefit additional MPG etc. Ford, GM and Chrysler would have used them a long time ago. All I am saying is, a flex fan will run when not needed, as compared to a more effiecient fan-clutch type of fan. A flex fan is an upgrade compared to a steel fan, yes. On an Aerostar with a shroud, air flow and cooling will be better with a plastic fan clutch type, as compared to a flex type fan. Check the internet, as there is articles backing my statements up. When I have some more free time over the weekend, I'll check it out for you. To sum it up, you can use a flex fan, but it will not draw in and move the air as effieicently as a fanclutch fan. Good luck in whatever you decide to use... Ed

 

I've heard a lot of pro's and con's. The thing about a flex fan is the blades are thin, flexible metal vanes. As the speed of the fan goes up, the blades "straighten" out, so as not to draw in additional air. This way, they only pull through air during slower speeds, and while idling.

However, with the design of the waterpump snout, I doubt there is a flaxfan spacer available to thread onto the pump to begin with. Leaving me with either the fan clutch, or an electric. I'd love to go power, but they are so expensive...

If I knew that my old beater that I'm trying to sell would be sold as a parts car, I'd steal the elec fan from it, and see if I could "retro-fit" them into the van...two, smaller elec fans...I'd just wire one to run constant, and have the second spin up from a thermostat...