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Which Evaporator?

Riptides99 on Tue July 13, 2010 1:44 AM User is offline

Year: 1989
Make: Ford
Model: Taurus
Engine Size: 3.0 V6
Refrigerant Type: R-12/134a
Country of Origin: United States

The car I'm working on has had the A/C replaced in it in the past by a local Ford dealership about 14 years ago. The entire system was replaced/updated to R134a parts, but the R12 freon reclaimed from the system was recharged back into it, at some point in the past 3 years there was a major failure in the system and all the refrigerant was lost. The failure was with the manifold line coming off the compressor at the lowest point of the bend so the system lost oil along with the freon.

I've got all new lines and a new FS10 compressor to replace the old previously replaced "FS10" compressor with as there was a ton of black junk in the outlet line of the old compressor.

I have successfully flushed both the Evaporator and Condenser.
I have leaked tested both these items and there is no leaks in them.
I will be vac testing this system when assembled but definitely plan on having a professional A/C shop test/recharge everything when I am done.
I have new pressure switches for this system, one for each type of refrigerant, based on what the shop suggests using.

During all this I took the opportunity to replace a blown heater core in the dash, and I pulled the Evaporator because it was packed full of debris on the fan side, it has been about 14 years since it was installed, and I wanted to clean the entire duct system out.

What I have found out in the mean time is that there are 2 different styles of Evaporator for this car.
One is a high air flow evaporator.
The other is a low air flow, high back pressure unit, that cavitates the air as it passes through it.

Mine was replaced way back when with the low air flow, cavitation unit.
But after the original replacement 14 years ago the A/C, heat, vent air, all tended to just SEEP from the vents.
Even though the fan motor and fan were replaced used OE parts around the same time because of the seeping problem, running the fan on high still caused it to only seep, never blow at the rate it did before the A/C system was replaced.

Here is the unit that was pulled from the car, no leaks, but stained from leaf debris in Vent housing.

Here are the two different styles that are being sold for this car, the left unit is the style that's in my car, the right unit is the same style as what's offered as OE Replacement and is by 4seasons.

My main question is should i keep the unit i have now or should i get the one that is the OE, higher air flow, style?
I sure would enjoy having the air blow properly out of the vents again.

Is there a difference because of the R134a refrigerant with either of these 2 different Evaporators?
Meaning left for R134a and right for R12? Because the system was updated for R134a refrigerant.

Or is it a matter of the one on the left being much cheaper than the one on the right that I ended up with the left one?
I can get the left one for around $80, the right one is about $130.

Edited: Tue July 13, 2010 at 2:19 AM by Riptides99

ice-n-tropics on Tue July 13, 2010 11:14 AM User is offline

I learned to not ever throw the doves on the passenger floorboard of my pickup. The recirculatipon A/C air will suck the dove feathers through the blower and clog the evaporator.
You have almost answered your own question with comments on abnormally low air flow.

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

Riptides99 on Tue July 13, 2010 4:24 PM User is offline

I've been racking my brain over the why was the car using parts that weren't actual OE if taken to the dealership for repair.
And I think I remember that the local small town dealership here didn't have the tools to do the system with properly so they sent it off to a "Ford Certified" shop who did the actual A/C replacement another town over.
Upon getting it back the air blew out badly so the dealership ordered some parts then replaced the fan motor and fan unit a few days afterward.

I understand now about answering my own question, it wasn't so clear until I really put it all down in the forum last night, about the bad air flow, and whether to replace it or not.

But would there be any difference, considering the style of evaporator, when going to a R134a system?

I fully understand the system being designed around R12, and it not being as cold with R134a, but didn't know if the style differences were because of the actual hardware conversion.

mk378 on Tue July 13, 2010 4:39 PM User is offline

The site sponsor AMA has a good price on an evaporator for your car, but it is not clear from the picture which type it is. When you have low airflow to the vents make sure the air doors are working properly and the fan motor is getting plenty of voltage. On some cars it is useful to modify the circuit and add a relay to apply full battery voltage to the fan on high.

The evaporator really isn't critical for conversion performance, it's all about the condenser. I doubt there is a big performance difference between the two. Note that it isn't just about airflow, the air has to actually touch metal on the way through the evaporator or it won't get cold. I had a nice "high airflow" radiator in my car after most of the fins corroded and fell off, but it wouldn't cool the engine worth a darn.

TRB on Tue July 13, 2010 4:53 PM User is offlineView users profile

mk378, it would be similar to the Spectra Premium image.


When considering your next auto A/C purchase, please consider the site that supports you:

Riptides99 on Tue July 13, 2010 5:51 PM User is offline

MK thanks for your suggestion and insight. TRB thanks for your confirmation.

I hadn't considered looking at prices on here because you don't have a Taurus 3.0 engine listed for the 1989 year, it's really the most common engine for those cars, you've got the 2.5 (4cyl), and 3.8 engines listed, which are the most uncommon. I would suppose the 3.8L engine is applicable to the Ford 3.0, but not to be confused with the SHO 3.0L which was an entirely different engine and setup.

I was only actually looking to either replace mine with the high air flow, or keep the one I have, since it is still sound, and free.
But I think I would be best served in keeping it as more air flow will reduce the temp and if I move forward with a conversion to R134a then I would gaining only higher air movement at the loss of even more cooling upon replacement.

TRB on Tue July 13, 2010 5:59 PM User is offlineView users profile

Web is just a starting point for all we carry or have access to.



When considering your next auto A/C purchase, please consider the site that supports you:

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