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98 Buick Century Evaporator

newton5 on Fri July 18, 2008 12:53 AM User is offlineView users profile

Year: 1998
Make: Buick
Model: Century
Engine Size: 3.3 (?)
Refrigerant Type: R-134a
Ambient Temp: 90
Pressure Low: 0
Pressure High: 0
Country of Origin: United States

Hi all.

I've got a 1998 Buick Century with a leaky evaporator in my shop.

I feel really dumb.
I removed the lower MVAC box cover and exposed what I thought was the evaporator. The leak detector was gong crazy. Aha! Found it!!!
I didn't see the telltale signs of oil staining though, hmmm.
Hah, being that exposed, no problem to replace the "evaporator'. Right?? Piece of cake!!

Come to find out, I was sniffing around the heater core. It's a cakewalk to replace, but unfortunately, it hasn't failed.
The evaporator appears to be much "higher" in the MVAC suitcase. It also looks like I'm going to be pulling the instrument panel to do this job.
Can anyone confirm the need to pull the IP? In this case, I would openly welcome being wrong.
It looks like the case is glued together and has screw bosses to refasten it if it needs to be separated. Yes..No...?

In my small business, I do quite a few Ford and Chrysler evaporators, which usually require removing the IP. I'm really short on GM evaporator experience, though. I just rarely see failed evaps on GM cars.
I know "how to remove an instrument panel", but are there any gotcha's on this particular model?

Thanks Much, Tom

BTW, Thanks, Tim!! I ordered the evaporator and it arrived within 3 business days. Even though the label said "Made in China" , the part has the look, feel and heft of a well made, quality part. I wouldn't expect less from AMA.


Edited: Fri July 18, 2008 at 1:07 AM by newton5

GM Tech on Fri July 18, 2008 8:33 AM User is offline

I'd be real surprised to see an evap leak from your Century- Have never seen a late model one leak yet--- hope you are sure- got dye out the drain? etc-- sniffers can go off at the weirdest stuff-hairspray residue, glues, solvents etc--

The number one and two leak locations on your car is the compressor shaft seal and body case o-rings usually drip with dye-- I'll never attempt an evap without 100% clarity.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

newton5 on Fri July 18, 2008 8:51 AM User is offlineView users profile

I zoomed right in on the compressor body and shaft seals first thing. Nuthin'.
As soon as I got near the box inside, the detector went crazy. A sniff of the drain brought the same result. I seldom use the sniffer, but my UV lamp burned out and I haven't replaced it yet. I'm pretty confident that the leak is in the evaporator. I checked it over 3 times and kept getting a positive hit in the box.
Of course i would get the one and only failed evaporator ever seen on this car.
Murphy wouldn't have it any other way.

Edited: Fri July 18, 2008 at 9:10 AM by newton5

GM Tech on Fri July 18, 2008 10:28 AM User is offline

When I get in a pinch like that-- what I do is pull out all the refrigerant- let the blower run for awhile to clear all traces-- then put my sniffer in the drain (make sure no water hits sniffer) - then get sniffer all set- make sure it is not getting any "hits"- then go ahead and pull a vacuum then charge a pound or so in-- Sniffer should immediately (within a couple minutes on evaps) detect the leak as soon as refrigerant is introduced- I do this on shaft seals as well- usually machine is still charging the one pound when sniffer goes off- I immediately stiop charging- and hit the recover button and the let the sniffer wind down. I call these "no doubters" hard to argue of any outside influences when you use this method..

Also, the reason I tell of V-5 leaks- is that you are right in the middle of prime canidates for the shaft seal- I do 3 or 4 a week from '96 to 2001 on V-5s- all with good shaft seal sniffer hits.- But I only check the ones that look dry- the wet oil slingers are "no-brainers"



-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Fri July 18, 2008 at 10:42 AM by GM Tech

newton5 on Sun July 20, 2008 10:59 PM User is offlineView users profile

Thanks Tech. I'll go over the compressor again. I planned to anyway, I really don't want to pull the IP.
That will be tomorrows project.

newton5 on Mon August 25, 2008 9:09 PM User is offlineView users profile

Well, I re-verified the evaporator leak twice, once back on July 21 and today when I started work on the car.
The customer brought the car back today for the evaporator replacement, she needed some time to save up for the repair.

Once I figured out the "GM thinking" on the instrument panel, it's not any tougher than others that I've done. It's just a bit different. The "dashboard" is basically a plastic cover to hold all of the accessories and instruments. Behind that is a large tie bar to support it. Someone from this forum sent me a couple of PDFs that were really helpful, Thank You Brian(?).

I got the cover loose but ran into a snag. I can't for the life of me figure out how to remove the driver side SRS airbag from the steering wheel. The wheel needs to come off for clearance to completely remove the plastic dashboard and the steering column opening is too small to clear the wheel.
I loosened the cover on the back of the wheel, but it is captive on the column. There appear to be 2 white plastic clips that hold the airbag in place. I can't quite see them due to the cover dangling in the way. I poked and prodded them gently but stopped when they didn't give any indication of how they were attached. (Murphy was in the back seat urging me to pry on them, but I resisted and stepped away... )
Any thoughts on removing the airbag? I'm sure it's going to be a "forehead slap" moment once I know how it's done.

Thanks for any input.

PS. I'm very familiar with working on and around SRS systems and have taken the necessary safety precautions.



Edited: Mon August 25, 2008 at 9:15 PM by newton5

GM Tech on Mon August 25, 2008 10:41 PM User is offline

Those are collars (or pins- I forget exactly which- been awhile) that meerly need to be pushed in a tad to release them- hold constant pressure on them and they pop right out-- my first one took me 1/2 hour to figure out- but it is really simple once you see it when it is apart-- again it is for ease of assembly- it just snaps into place

I first saw them on a 95 suburban.. The more I think about it- I think you just use a flat object like a 3/8 extension and just push in on the end of the pins- they are spring loaded and release very easily.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Mon August 25, 2008 at 10:56 PM by GM Tech

newton5 on Mon August 25, 2008 11:37 PM User is offlineView users profile

GM Tech,
You're real close. Unfortunately, I can't push on the "pins". The loose "bottom of the steering wheel cover" is in the way. The only access is from the sides, and pretty limited, about 1/2-3/4".

There are 4 metal "pins" that protrude from the airbag module with springs wrapped around them. Those pins are beveled on the ends. They pass through the steering wheel "structure" and seem to be held in place with some sort of plastic clips on the back side of the steering wheel "structure". One rectangular "clip" for each 2 pins, left and right.
I now see that the "clips" are positioned into the mounting holes on assembly to form "collars" of some sort around those pins. I assume they lock into grooves in the pins.
Looking close, I can't see how to release them.

GM Tech on Tue August 26, 2008 12:40 PM User is offline

You have to push the pins in to release them-- the steering wheel must be rotated correctly to access them-- if the loose cover is now in the way- put it back or remove it-- you'll never get the wheel off other wise

Why do you need the steering wheel off anyway? I usually just lay the whole column on the seat- or remove it completely- but don't need to remove air bag to do that...

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

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