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Discussion Starter · #1 · (Edited)
Guys,

A little back info, For the A/C I Replaced the Compressor Last Year and the A/C worked Good. Now fast forward to this year and No A/C, well Apparantly the Compressor Somehow siezed. So I Replaced the Compressor with a NEW Unit, and Totally evacuated the system New Accumulater, Orifice Tube, Low Pressure Switch on Compressor, etc...and attempted to ReCharged with R134 (That was done at my A/C Shop)....But the Clutch would Only Engage if it was Jumped it....Soooo then I Replaced the Module with a New One($$$$), as well as the Head Unit New Old Stock ($$$$)..as well as a New Blower Motor.....
So Now I STILL can Not get the Compressor Clutch to Engage!!! The System itself operates Great though with the New Head Unit, Super fast and quick to go from Vents to Floor with heat....Ideas?? I Need A/C...Thanks!
 

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'84 Eldorado and Seville
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Did you check the cycling switch? Located somewhere near the accumulator. Line sensor probe is covered by the black colored cork tape. Somewhere in the service manual it explains what voltage should be returned to the blower resister module.
 

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Discussion Starter · #3 ·
DB2, I Replaced the Switch on the Compressor (Low Side) yet I could NOT Find Another switch...! The Accumulator has No Switches on it...I've seen the Switch your talking about in Other GM cars (G-Body) but these have Nothing!
 

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'84 Eldorado and Seville
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Should be GM part number 3046558.

The black cork tape NAPA sells and probably other places. Something like $24 a roll seems like.

GM Parts giant has that cheaper than eBay vintage gougers.
 

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Discussion Starter · #6 ·
Thanks, yes, I googled After I replied, and I Think you Nailed it...👍❗That Is the Only switch i Didn't replace...Thanks..
598395
 

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Unrelated, BUT you have to wonder why the new compressor failed in less than a year.

Based on what you said, we don't know why you replaced the first compressor, but if it failed and put debris into the system, and you did not replace the condenser and flush the system when you replaced all the other parts, that debris will recirculate and eventually take out the new compressor, which sounds like what might have happened.
 

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Discussion Starter · #8 ·
Ranger, Yes, I Did a Complete Flush, Replaced the orifice tube, However i did Not replace the Condenser, it Would be a Good Idea to Replace that Too though!!
 

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Discussion Starter · #9 ·
Just to Update here, it works Great Now ....the Problem turned out to be that Everything Was Working, It just Needed a Fill of 134A as my Shop was Unable to do the Fill initially as the Compressor would Not turn on do to a Bad Module AND Head unit, which, as I Outlined Above, I Replaced with NEW GM ones I found on Ebay..$$$$!!
 

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Probably more times than not some of those switches, low pressure cutout etc, are actually doing their job. Glad you figured it out.

Scott
 

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Discussion Starter · #11 ·
Kinda Spoke Too soon, Now it's the Vent temps...49-60...They 'Should' be High '30's...And yes the Blend door IS Working...Uggg...Condenser maybe??
 

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If you know the proper temps does that mean you have a service manual? It seems it could be the system or it could be the air/temp control. Is the evap outlet pipe cold? Is the compressor running constantly or is it cycling on/off frequently? If the manual has a diagnostic tree you may want to go through it.

Regarding your condenser question the condenser is part of condensing but airflow is the other part. If you suspect the condenser you can always test the theory of better condensing by improving the airflow. But that said better condensing will typically improve the AC discharge temps. Improved condensing plus a change in orifice tube diameter were the 2 major changes for R134a other than durability/oil related items. Also make certain the condenser fins aren't folded over if you suspect condensing.
 

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Discussion Starter · #13 ·
Thanks, I'm going to Put a New Condensor on, and I Did hear that a Lot of shops put Too Much Sag Oil in the Compressor?? Something also about Ester Oil instead? And Yes I have a Service Manual...Thanks!
 

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You mean PAG Oil. The problem is it's not obvious how much oil is left in the system. The compressor will have some, the "AD" (Accumulator - Dehydrator) will have some, the evap and the condenser will also have some. The amount each has depends on the running conditions and any migration after shutting down the system and extracting the charge. The alternative to PAG is POE. PAG was the original factory fill for R134a when it was introduced to the market on GM vehicles because the prior "mineral oil" used for R12 was not miscible with R134a (didn't mix/travel well with R134a so lubrication was compromised if oil cannot make it back to the compressor). POE seems to be commonly recommended now because POE is compatible with both R12 and R134a. One thing you need to be very careful of however is if a system was EVER switched to R134a and they used PAG. Once PAG is in the system you can never go back to R12 because R12 + PAG = ACID and you will destroy your system. You're using R134a so there is no risk of having trace amounts of mineral oil but it still could go to your point of having too much oil in the system. If you had a full "charge" of mineral oil still in the system and the recommended PAG or POE was added the mineral oil is still there and sitting somewhere or shifting; just not as efficiently.

A better condenser will almost certainly improve the AC but my point was it may not be the main issue. Before you open the system again I would try to investigate further. How cold is the evap outlet pipe? If the evap out pipe is getting very cold then the problem is on the air handling/ temp control side and not on the actual AC loop side. The manual I found listed the semi automatic temp at 34F with 70F ambient but with R12 (It will be higher with R134a). Your evap needs to be even colder than 34F to get that air temp. A better condenser will probably get you a couple of degrees.

I would start with the diagnostic tree and see where it leads you.
 

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Discussion Starter · #15 ·
Thanks! And one more thing, is that our climate control system on these cars has NO Recirculate Button, which would Also help a Lot!!
 

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I don't know the control head on your '84 well but if there is any setting referred to as "MAX" that is the recirc mode. One thing to note though all GM vehicles have at least a minimum amount of outside air even in recirc. Without some outside air you can experience a condition where your windshield fogs suddenly.

The "Max" is very misleading because some may think it uses more energy but in fact it's the reverse. Since max is recirc the load on the evap is less so the system isn't working as hard.
 

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To be honest I've never been a big fan of fully automatic systems. In addition to my '79 Eldorado I have a '79 Toronado. The Toronado has the "Tempmatic" System which is the semi-automatic system. The Tempmatic still controls to a temperature but you control everything else like mode and fan speed. IMO the semi-auto control is the best regardless of the car I'm; control the temp and let me have control of everything else.
 

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For some reason GM on my 2011 Duramax they wrapped the accumulator in a foam like form with foil covering. Could be due to the heat from the diesel engine also. Almost sure it is running R134A. The foam pieces come in 2 halves. I got a set and was going to put them on a Fleetwood running 134 just to see what if anything that does but I haven't had a chance to.

598947
 

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Discussion Starter · #20 ·
Well I'm going to First put on a new Condenser...However, my Accumulater Does get Ice cold...Just Not my Vent temps...Thier at 49-65degrees...
 
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