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boatmoter on Thu July 05, 2007 5:35 PM User is offline

Year: 1991
Make: ford
Model: exploder
Engine Size: 4.0
Refrigerant Type: r134-a
Ambient Temp: 96
Pressure Low: 43
Pressure High: 253
Country of Origin: United States

have replaced compressor (new,not reman) > condenser > got orfice tube from dealer > accumalator >
> heater core > flushed system > put in factory recommened amount of oil > weighed r=134-a >
installed add on electric fan > replace fan clutch with heavy duty > evacuated with a 5 cfm pump for 4 hours, > does not cool very well even when driving. worse when idling >has been this way for 2 years > turn compressor off and does not blow out hot unless the temp lever is moved to hot > also.. sweats great >> always open to suggestions..

ALSO, SINCE I CAN POUR WATER OVER THE TOP OF THE CONDENSER, AND THE READINGS GO LOWER AND THE AIR GETS COLD COMING FROM THE VENTS,/ but - putting large fan in front of condensor does not make a difference..

WANTED TO RUN THIS IDEA PAST YOU GUYS.. FABRICATE A HEAT EXCHANGER THAT WOULD GO OVER THE HIGH SIDE TUBE,CLOSE TO THE CONDENSER,RUN ANTIFREEZE THRU THE EXCHANGER WITH A ELECTRIC PUMP, HOOKED TO A ADDED HEATERCORE UNDER THE HOOD WITH A ELECTRIC FAN,SO THE HI SIDE COOLS DOWN SOME BEFORE IT REACHES THE CONDENSOR.. I FIGURE THIS WOULD MAKE THE AIR COLDER WHEN IDLING AT STOP LIGHTS AND IN VERY HOT WEATHER.. I KNOW THAT SOME HOME A/C UNITS HAVE THE HI SIDE GOING DOWN TO THE BOTTOM OF A WELL THEN BACK TO THE CONDENSOR.. appriciate all input and comments..

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Glenn //

mk378 on Fri July 06, 2007 10:41 AM User is offline

The obvious thing would be to revert to R12. If you really must run R134a, converted CCOT's can benefit from tweaking the charge amount and orifice size. Since the high side pressure tends to be higher, installing a smaller orifice keeps the flow rate closer to original design levels and allows a lower low side. Fit thermocouples on the evaporator lines and charge until the outlet is the same or colder than the inlet.

Rather than the water-cooled idea, install an extra condenser in series with the stock one (on it's own fan system) instead of the heater core. Or better yet, replace stock condenser with a parallel flow unit.

steve325is on Fri July 06, 2007 10:48 AM User is offline

A 1991 Exploder would probably be the LAST vehicle that I would do a 134 conversion on, especially an early production example. I worked for Ford in that time period, and they did not cool very well even with R12. Ford had an "update kit" for the early build 91s that helped a little.

My 2 cents (or is that .02 cents?)

-- Steve

TRB on Fri July 06, 2007 12:02 PM User is offlineView users profile

Quote
Originally posted by: steve325is
A 1991 Exploder would probably be the LAST vehicle that I would do a 134 conversion on, especially an early production example. I worked for Ford in that time period, and they did not cool very well even with R12. Ford had an "update kit" for the early build 91s that helped a little.



My 2 cents (or is that .02 cents?)



-- Steve

I agree with this comment.



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boatmoter on Sat July 07, 2007 5:22 PM User is offline

I did a little research on the parallel flow condenser and Im finding dead ends.. they are designed and built by modine, but distributors I talked to say its not avalible for a 91 exploder.. I did seal up around the condenser today and changed the thermostat from a 195 to a 180 degree to lower engine temp a bit,will cost a little more gas,but anything to get the air colder..I don't have anyroom that I can see to add another condenser, one distributor said he had a serpentine condenser for $153.00 Im thinking that thats a stock oe style condenser,althou he said the cooling is 20% better than the oe style.

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Glenn //

iceman2555 on Sat July 07, 2007 10:42 PM User is offlineView users profile

Increasing the efficiency of the condenser would be of great benefit.......nothing beats the extra heat transfer....but from the posted pressures and the posted ambient temp....seems the vehicle is a bit undercharged. Insure that the system is fully charged....test the evap inlet and outlet temps with a high heat load on the evap....doors open during testing.....max cool.....engine at idle.....charge until the temps balance or fall within 3-5 degrees of each other.
Most aftermarket condenser mfg'ers are making new replacement condensers that are more efficient than the OE tube and fins. Many or 6mm pics and work very well. GM used a two tube/pass serpertine condenser on some Tahoes and they worked well. Do not know of a condenser mfger that makes those however. Check with site sponsor....TRB may have a suggestion for a replacement condenser. Not sure when they made the change...but some later model 91/92's had a parallel flow condenser as standard equipment. Get the charge level correct and then attack the problem of a high side pressure problem...it it occurs.
Also what type of flush was used.....if an ester based flush...this could contribute to the problem also...this chemical is almost impossible to remove from the system.
Keep in mind....this vehicle was designed for R12 and will work best with R12 !
Good luck!!!

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

steve325is on Mon July 09, 2007 10:35 AM User is offline

Not sure if you have the Super Cooling package or not, but Ford recommends replacing the standard fan and clutch with the super cool version if you don't. Another TSB installs a water shutoff valve to remove heat bleedover from the heater core.

A 3.73 limited slip differential is a typical sign of a trailer package on the 1991s, and that would include the extra cooling package. A 3.45 open diff was standard and would lead me to believe that you have the standard cooling package.

-- Steve

boatmoter on Mon July 09, 2007 8:35 PM User is offline

mine has the thicker heavy duty radiator and a new heavy duty clutch.. also says on the sunvisor that it has the off road package,but its a 2wd.engine runs cool even in 98degree weather. after reading the feedback on my post,Im kinda thinking that its needing a condenser that will cool the freon down better.
I can run water over the condenser and the high presurres drop and it will freeze you out inside.
drive it down the road and its nothing like the water on the condenser. I am leaning on the reply I recieved for installing a parallel flow condenser in it.. I read up on them and it sounds like what I want to try first.I thank everyone for the advice and comments on my post..

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Glenn //

NickD on Wed July 11, 2007 8:17 AM User is offline

Practically all the first MVAC systems used a sight glass in the high side line to show instantly whether you are applying a liquid or a foam to the orifice. It seems that liquid cools much better than foam. But the sight glass can be considered more experimental in the sense that for a large production run of close tolerance AC components, can just tell a guy to put in so many pounds of refrigerant, no need to see whether you have liquid or foam, if everything is stock, implicitly, it should be a liquid.

One might concur that switching refrigerants from the designed component that the system is no longer stock and hence, now the system is experimental. So perhaps it is justifiable to add a sight glass as we are back in the experimental stage.

But you just cannot pour in R-134a into an R-12 system until you get a clear sight glass, unfortunately, for the same volume, they gave us a refrigerant that operates at a much high pressure than R-12, the system will blow up! It's not too bad at the lower temperatures, R-134a is only about 10% greater than R-12. But the increase in pressures with temperatures is not linear when comparing R-134a with R-12, R-12 tends to have more of a linear increase where R-134a tends to skyrocket in pressures as the temperature scale goes up.

R-134a wasn't exactly the ideal refrigerant to put into an R-12 system, if anything, a refrigerant should have been developed that has a slower increase in pressure as the temperature curve goes up.

Ford's response to this situation was simple, just do a complete firewall forward conversion. It's also typical when an industry screws up that they make compensation to the consumer. I mean that the risk of a spec of asbestos coming off an electrical appliance, going up ones nose and causing lung cancer is very remote, but yet all the manufacturers of these products had to eat this up when it was learned that some workers working in a dense cloud of asbestos dust may have been the cause of lung cancer. But R-12 was theoretically thought to punch huge holes in the ozone layer that would be the end of mankind, this is major.

And who was the cause of this? Certainly not the consumer, the consumer paid good money for this earth destructing devices trusting that the manufacturers knew what they were doing. But where did the liability fall, on the historical manufactuers of these hazardous products? No, they fell on the consumer.

Don't you find it ironic that the huge majority of consumers never filed a complaint? Sure a manufacturer has the right to change materials in new products, but what about the liability of the older ones? Ford didn't give that kit away, expected you to pay for it. But have to blame the government for this one, they are the ones that banned R-12 in most countries, little more merciful here, just taxed the hell out of it. You can buy all the R-12 you want just like buying gasoline, just dish out the cash. But in other industries, the companies were held responsible and many went bankrupt, guess the big three has more pull.

What was really a hazard and probably the cause of the nuts we have leading this country is leaded gas, but that was given a twenty year phase out period, R-12 based on a theory by a couple of hippy scientist was banned instantly.

So you want more cooling and switching to R-134a is already a major move in the wrong direction, but can add a sight glass and attempt to get it clear by playing with the only remaining parameter, temperature, that has got to be lowered. Ironically, with these refrigerant based cooling systems, the greater the temperature, when you really need more cooling, the efficiency of the system goes way down. Ha, guys selling HVAC systems like to give COP numbers at 68*F, but normally do at 85*F, but never see anything given when it's greater than 100*F outside.

Then there is the issue of expense, from my old poor thinking, put a lot of bucks in a 89 Continental AC system when that vehicle was only eight years old, yours is sixteen years old. Man, that system cooled great, best MVAC system I have ever had. But the first sign of being a poor investment when the car was running and looking great was going to my Ford dealer to learn he would only give me 100 bucks on a trade in for a later model car, but if I didn't trade it in, would knock off a thousand from the price of the car I was looking at. Said I would get my use out of it. That didn't last long, in a 80 mile trip, blew a head gasket, AXOD starting slipping like crazy, and the car went flat as the struts blew all at the same time, $3,500.00 just for parts, goodbye Ford. And goodbye to an AC system I spent hours on.

So is fooling around with an old Explorer really worth it? With the high price of gas, our dealers can't even give SUV's away.

boatmoter on Wed July 11, 2007 8:30 PM User is offline

I used to work for ford,Im a ase master tech. and ford certified..my point is my 91 explorer is in great condition. and the 6 banger is also great on gas. and I also use it to pull my boat,great for pick ups at home depot. this truck is really tight.and Im now self employed as,a vender.. its great for servicing the machines on my route. I have had this a/c problem that has me at a dead end .. the a/c did not work when I purchased the truck 8 years ago.but thanks to the comments from members from this forum. I have one suggestion from mk378senior member suggesting that I replace the condenser with a parallel flow condenser,I did some research on that and read up on the theory and description of the parallel condenser ,thought about the changes and the outcome of the test I have done and parts I have replaced,I believe that senior member mk378 is right and Im going with his suggestion.. this explorer is one of the most dependable and
easy drivers that I have had since my 1969 dodge dart swinger..but, yes..its worth saving..I also have thought about a new truck,but a/c repair $ verses new truck payments$ .. Im also going to replace the condenser in my saturn with a parallel flow..

































4 and higher insurance.

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Glenn //

boatmoter on Wed July 11, 2007 9:54 PM User is offline

I feel its kinda wierd that R-12 went off the market and R134-A came on just when duponts patent on R-12 expired..

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Glenn //

NickD on Thu July 12, 2007 8:07 AM User is offline

Actually the patents on R-12 have been expired for years, maybe just kind of weird that DuPont just received patents on R-134a. A parallel flow condenser has approximately a 25% increase in heat transfer, but you will have to try and squeeze out the actual performance value from the manufacturer and how this increase in heat transfer translates into reduced high and low side pressures remains to be in the experimental stage.

R-134a does have the ability to transfer more heat from the evaporator to the condenser than R-12 accounting for increased pressures and kind of a debate which refrigerant would be the better choice. One option is to use both R-134a and R-12 compatible components, in particular the accumulator and an oil such as BVA-100, and if R-134a is not satisfactory, recover it, draw a deep vacuum and try R-12. You will need a 609 certificate to buy R-12. But in either case, would go with the parallel flow, since your system is already hurting.

boatmoter on Sun July 15, 2007 11:23 AM User is offline

I went to the salvage yard for some parts and looked at a few 94 saturn's,
found that the saturns come with a thin and pretty good size condenser,and they are parallel flow,going to do some measuring to see if they are small enough to fit on my explorer,if so Im going to put two of those togeather and hook up in series and have the hi & low pipes off a explorer heli arched and install so the hoses snap right on.and going with a full load of R-12..
let you guys know how it turns out.. and the purchase will be providing theres no black death on the saturns..

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Glenn //

bohica2xo on Sun July 15, 2007 2:18 PM User is offline

So why would you shoot yourself in the foot with a pair of junkyard condensors?

There have been several discussions on this board over the years regarding multiple condensors. The OEM's that do this always put them in series. The two choices are:

1) As a Pre-Cooler. A tube & fin unit mounted BEHIND the main condensor, with the compressor discharge routed through the pre-cooler to the inlet of the front condensor. Or a primary cooler mounted in a different location, Porsche does this on some vehicles.

2) As a Post-Cooler. A smaller condensor mounted in a seperate area, to provide additional sub-cooling to the liquid refrigerant, AFTER it leaves the main condensor. Dodge does this on some minivans.

Parallel flow condensors are designed to work from gas to liquid. Two of them in series is not the best plan.

My first choice for that vehicle would be to retrofit the 1999 & up Explorer Condensor, or even the whole cooling package. The Late model Explorers have a well done & sealed package. Perhaps a cut & replace on the whole radiator support?

If you must add a second heat exchanger, I would use the Dodge Caravan post-cooler to sub-cool the liquid. It is a serpentine unit made for liquid.

The thought of two junkyard condensors that are not even close to the same size as your OEM condensor makes me shudder. It would be less work to swap the radiator support for a late model exploder setup. New condensors are not that expensive.

B.



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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Sun July 15, 2007 3:15 PM User is offline

Wrecking yards around here charge dealers list for old rusty scratched up junk parts, what is your wrecking yard charging for a pile of crap?

Most are now using undocumented Mexican labor, but still claim their overhead is high and won't let a guy go out in the yard to take off his own parts. They have two tools, an acetylene torch and a hammer.

boatmoter on Sun July 15, 2007 4:46 PM User is offline

I can believe that.. but here in tampa we have a few salvage yards that charge you a few dollars for admission to go in and pick your parts and remove them your self, there is always around 1500 cars to sift thru,and all the brands are togeather..there is no cheap labor working here,not yet any way.. the condenser will go for around $15.00.. I have gotten complete dash assemblys for $35.00.. transmissions $50.00,and parts are warranted for 31 days.. what state are you in??

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Glenn //

NickD on Sun July 15, 2007 5:00 PM User is offline

Wisconsin, wasn't that way about 30 years ago, 50 years ago was great, about 50 cents per bushel basket full of parts. Crazy today.

boatmoter on Wed July 18, 2007 5:52 PM User is offline

Hey guys,I think I found a way to get a little cooler in my car..
gonna get the windows tinted saturday..

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Glenn //

MikeH on Mon July 30, 2007 6:46 PM User is offline

I purchased my '91 Explorer new and wanted to keep it. So, when I lost the A/C compressor on my '91 explorer 3 years ago and considering the replacement cost decided to make the 12 to 134 conversion.

I got the kit from Tim and it took about one day to put in.

While the 134 does cool pretty well, I don't think it cools as well as the original 12 system. I live in Dallas where the sun creates an oven with a parked car. When I first bought the Explorer, it took about 3 blocks to cool with an outside temp of 95F. Now it takes about 1-2 miles. And, even then the cooling is not as good.

Given the cooling, I would still recommend the conversion as 134 is a LOT cheaper.

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