3800 swapped AC Questions (Page 1/2)
AndrewTHG MAR 07, 02:19 PM
Hey All!

So I am working on getting my AC back up and running. 1987 GT with a 2004 3800 in it. I am a bit confused with the info I have found on the o-rings that meet the body in the engine bay, as well as those that are for the compressor..

As for the engine bay hard line to flex line joint (that runs to the compressor and was modified to have 3800 compressor ends on one side, and fiero fittings on the other), from the threads I have read, 85-88 should use a standard o-ring type for a fitting with no taper. However, looking at the fitting (see pic), it somehow seems like mine are tapered, which would be a captured o-ring?

And then where that flex line then meets the back of the compressor, since I have the 3800 compressor, I believe I need the flat sealing washer style, instead of the o-rings, correct?

Thanks!
Andrew
sanderson231 MAR 07, 02:26 PM
I don't remember what compressor the 3800 uses but if it is an HR6 like on a 4.9L there are about 5 different versions of how the manifold seals to the compressor.

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

AndrewTHG MAR 08, 08:37 AM
From what I can gather it should be part number 15-32241 which provides two "sealing washers" that go between the lines and the compressor. Not positive though, as mine did not come with anything but that is what I have found so far.

As for the hard lines, I am thoroughly lost on this one. Everything I have found on PFF points to 85-87 having a "square shoulder" on those connections but they look pretty tapered in that picture above. Debating just trying to find something close and go with it. Not sure if that is the better move, or just keeping the existing black o-rings.

And does the existing wiring still plug into the accumulator, or is it just unscrewed and left unplugged?

Lots of questions here, I am no AC guru by any means.
KissMySSFiero MAR 08, 10:14 AM
Andrew,
I've been building the AC hoses for swaps for about a year now. When I build hoses, I send new o-rings for the compressor side(the first few I built did not get them)

There are 3 basic differences in the compressors.
The common one we use in the swaps is the Series 2 or early compressor. It is out of a GrandPrix or other W-chassis cars. It has equal size ports. They are a 5/8 flat washer type of seal.
https://www.rockauto.com/en...82521&pt=13290&jsn=1

The other early compressor is more difficult to use. It has one port larger than the other. So the hose manifold on the compressor is different. It also routes towards the front of the engine. With the different port sizes(5/8" and 3/4") it would need heavy mods to modify the correct hoses. It probably won't seal using the other style hoses with 2 of the 5/8" seals.
https://www.rockauto.com/en...442&pt=6900&jsn=1321

If yours is a 2004, it may be the scroll type compressor. Which has different size openings for the suction and discharge ports. I think they're 1/2" and 3/4".
You're compressor hoses would look like this.
https://www.rockauto.com/en...91&pt=6900&jsn=10954

All of the compressor seals are the washer type.

Don't leave out the compressor pressure transducer fitting. The sensor is used so the PCM can control the compressor.

I'll try to edit this later with my own pictures.

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SSFiero@Aol.com

olejoedad MAR 08, 11:26 AM
Andrew, the sensor in the accumulator is removed, and the two wires on the plug are joined together.

The 3-wire pressure sensor (in the chassis to compressor manifold) senses the A/C pressure fluctuations and the PCM controls compressor clutch engagement.
sanderson231 MAR 08, 11:48 AM

quote
Originally posted by olejoedad:

Andrew, the sensor in the accumulator is removed, and the two wires on the plug are joined together.

The 3-wire pressure sensor (in the chassis to compressor manifold) senses the A/C pressure fluctuations and the PCM controls compressor clutch engagement.



Not necessarily. My 3800 swap (1995 engine) done by somebody else uses the pressure cycling switch. My 4.9L swap also uses the pressure cycling switch. The A/C was controlled by the BCM in the Deville. The BCM is not present in the Fiero.

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

olejoedad MAR 08, 05:19 PM
As his drivetrain is from an '04, I would strongly suspect the A/C is s under PCM control.

I have made harnesses for both PCM and manual control of the A/C.
The PCM does a great job.

[This message has been edited by olejoedad (edited 03-09-2023).]

sanderson231 MAR 08, 10:35 PM
deleted

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

[This message has been edited by sanderson231 (edited 03-10-2023).]

RWDPLZ MAR 09, 01:12 AM

quote
Originally posted by AndrewTHG:
However, looking at the fitting (see pic), it somehow seems like mine are tapered, which would be a captured o-ring?
Andrew



Yes, these are captured o-ring fittings, never seen these with the captured design, usually they're standard/straight:





Assuming nobody changed it, maybe this was a late change to improve sealing? They would use captured #8 and #12 o-rings.
AndrewTHG MAR 09, 08:23 AM
Great info everyone!

SSFiero - I am an 04 with the different port sizes, so I went ahead and ordered the 15-32241 seals which ought to work. I also have the pressure sensor in the lines I had made (P/N 13587697 with o-ring P/N 19188397).

Joe, I hope all is well! Okay, I got a new accumulator so I will just leave that port empty and cut/join the wires. You made my harness about 5 years ago (wow how time flies) and it does have the 3-wire plug there. I've just had it zip-tied up for a while, waiting to do my AC. So it will be PCM control of the A/C.

Agreed, strange on the captured design for those lines. It contradicts all the info I have found for an 87, and as far as I know they were never modified after the fact. This is a 2 owner car with the only 2 owners being me and my dad and he never modified it. I'll try the captured #8 and #12 o-rings. It will be interesting to see if the other O-ring P/N's match up with what the 87 data says they should be.