Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Compressor seized

58pacer on Sat August 23, 2008 11:49 PM User is offline

Year: 1993
Make: Mercury
Model: Sable
Engine Size: 3.8L
Refrigerant Type: R134a
Ambient Temp: 100F
Pressure Low: 40
Pressure High: 170
Country of Origin: United States

So my new compressor started chirping and siezed about a month after installation. It was a new one from a Ford dealer. I used the old clutch, a new replacement Chinese accumulator, a new splice-in orifice tube, and I blew the evaporator, condensor and all old connecting tubes out with Hecat in the forward and reverse directions, ending in the recommended direction for each component and then blew each component clean with dried air from my compressor for about 1/2 hour each, or until no moisture appeared at the outlet.

Put in a total of about 6 oz. of the correct oil, about 2 oz. into the accumulator, and 4 oz. into the new compressor. Evacuated, then charged with 30 oz. of R134a. Had some problems getting the compressor to turn without smoking the clutch because ambient temp was high and coolant was going in slow. I gave up for a while, then later in the evening when it was cooler, I was able to coax a little more coolant in, allowing the compressor to cool between tries. Eventually, enough coolant got in to carry the oil, and after I got up to about 12-14 oz., the rest went in fine. Output air temperature got down to 43 degrees F, and I was happy.

Pressures were in the range of 40 low side and 160 to 180 high side.

But now it's toasted. Anything I should check in advance of opening the system and doing a post-mortem on the compressor?

TRB on Sun August 24, 2008 2:42 PM User is offlineView users profile

Let us know what you find in the OT. I have a feeling there was still debris in the condenser. The 6mm condenser is flushable but its design leads to bypassed passages. I suggest replacement on this style condenser.


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

bohica2xo on Sun August 24, 2008 3:42 PM User is offline


"Had some problems getting the compressor to turn without smoking the clutch because ambient temp was high and coolant was going in slow"

Tells me there was an issue with either the compressor, the used clutch or the charging method...

That particular car has the low side port right at the compressor inlet. I have seen compressors damaged during charging before with that vehicle. The refrigerant entering the compressor takes the oil with it, and nothing is returning yet. I would be sure to charge the repaired system like this:

With the engine stopped, and the system evacuated charge as much of the total charge as you can as a liquid. Charge the liquid through the high side port only to avoid washing the lubricant from the compressor. If you are using cans, you should be able to get the first can in very quickly. It may not take more than that because of the equalization that will take place while changing the can. If you are using a bulk cylinder, be sure to monitor the scale to avoid overcharging.

Once you have a partial charge in, close the high side valve on your manifold before starting the car.

Finish charging through the low side port. Do not jumper the cycling switch. If it is short cycling, let it.

A new compressor install should not be so difficult to turn that the clutch smokes.


Edited to add:
I completely agree with Tim, would put that condensor in the trash now that it has had a compressor come apart. Just not worth trying again.

"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.

Edited: Sun August 24, 2008 at 5:38 PM by bohica2xo

58pacer on Mon August 25, 2008 1:26 PM User is offline

Probably charging method was the culprit...I agree that putting liquid in on the high side would have been a preferable technique. All the references I used said not to do it, probably because some yo-yo might try it with the compressor turning! BTW, the low side port on this particular installation is at the accumulator outlet back at the firewall, so it wasn't quite as close to the compressor inlet as you might think. Still, it didn't seem as though oil was returning as fast as it should, and without a significant charge to pull it around, with 20/20 hindsight I can see why I might have sustained early compressor damage.

But if the orifice tube is still intact, wouldn't that have caught the junk coming off of the siezed compressor? I know what you'll say..."Do ya feel lucky, punk?...well do ya?" Why would it have gone a good month of continuous use before finally getting noisy and seizing?

It almost seems as though the lubrication was insufficient or the wrong type. I'm assuming I put the right stuff in, and enough of it.

Perhaps you could give me a little rundown on what oil to use and how much I am going to need when I replace the condenser and compressor. How about accumulator, is that going to need to come out too? Is the old evaporator still safe to use?

How about mixing oils with the type supplied already mixed in the coolant? Will PAG Blue mix safely with residual lubricant that might have been left over from a conversion using Quest R-134a High Mileage Vehicles Refrigerant with Stop Leak?

Will let the forum know what I find.

bohica2xo on Mon August 25, 2008 2:17 PM User is offline


I was thinking Cougar, not Sable. On the T'Bird / Cougar, the low side port is about 2 inches from the compressor suction port. Sorry for the mix-up.

You mention mixed oils, and sealant. You should really flush the evaporator to bare metal, replace the condensor & accumulator. That is the only way you will know for sure how much & what kind of oil is in the system.


"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.

iceman2555 on Mon August 25, 2008 5:28 PM User is offlineView users profile

The compressor operated for a month and then this the crux of the problem? The compressor 'died' because the system was not properly charged from the very beginning or there is a leak in the system. The loss of lubricant migration occurred because of insufficient refrigerant to maintain flow. The compressor gradually pumped itself dry and then, because of lack of lubrication, seized. More than likely, the compressor became noisy prior to this failure.

The serious down side to this repair.....a strong suggestion would be to replace the entire system....the evap can can be easily cleaned. The condenser....if it is truly a 6mm pic is almost impossible to flush....not so much as a PFHE...but still very difficult to clean properly. The flow of this condenser is thru the first four tubes...then a multi-pass unit to a exit (liquid) may be only two/three tubes of flow. Normal flush procedures lack the proper cleaning to completely clean the inlet area....flush takes the path of least resistance..... Removal of the condenser...completely filling with flush chemicals.....plug openings...let unit remain stationary for a period of time....20-25 minutes....then purge the flush chemical in a reverse patter...blow from the outlet with an exit from the condenser inlet. This is the most efficient method of remove debris from the condenser inlet area.

Insure that the system is properly and completely recharged....relying on pressures is not a good indication of a complete charge. For a DIY'er without a method to know exactly how much refrigerant has been introduced into the system....try this...Max Cool...Hi Blower....Engine Idle....DOORS OPEN. If desired follow the suggested method of charging one can...two if possible as a liquid...often warming the can will aid in this procedure.....engage the compressor....and complete recharge....allowing for sufficient refrigerant to precharge manifold/hose assm.....charge until the inlet and outlet of the evap are basically the same temp. If lacking the proper equipment to measure the temps....use your fingers....allow the system to stabilize...this can take 5-10 minutes...and recheck these temps....adjust as necessary.

If an excessive high side pressure is encountered.....adjust as necessary. Keep in mind with ambient temps 100 and above the high side pressures may exceed 265-275 psi. If this is a retro fit...the pressures may be a bit higher. The idea is to keep the evap flooded to insure correct lubricant flow. This is an extreme heat load on the system.
The pressures posted in this post are too low.
When the compressor is removed from the vehicle....turn it on its tail and drain lubricant from the compressor.....have a feeling that little to no lube is drained.

Adding lube to the system....esp after a complete flush....lube recharge is 7 oz....8 would not be excessive...esp since a bottle of lube contains 8 oz....add the extra oz....the system can handle it.....add 3 to the compressor.....add the remainder into the inlet of the accumulator....this will insure sufficient lube to maintain the compressor during start up.

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

HECAT on Tue August 26, 2008 9:30 AM User is offline

Don't have all the facts but...

First failure required new compressor, spliced in o-tube, and blow out with Hecat flush.

What happened to the original o-tube? Was it removed?

As far as a postmortem inspection; when inspecting the o-tube from the spliced in device, don't forget to look at the screen in this device before the o-tube itself. That screen will catch debris that will not be seen on the o-tube. Also inspect the inlet chamber of the condenser (back blow with some air, if necessary); the small passageways in these components make this chamber trap any larger debris from a failure, as they are too large to travel any further.

If previous failure include metal debris from the compressor, and only a "pour in blow out " flushing method was employed; this is very risky. Such severe debris issues can only be removed from the complex multiple pathways in todays components with effective power flushing methods.

If you have mixed oils and have been using refrigerant with sealer, you will need to flush to bare metal and start with a clean and dry system. Condensers are commonly replaced when a high debris load is present and effective power flushing is not available. Evaporators can usually be flushed in place and blown dry (blow, blow, blow). But sealer is a system can be a "death sentence" and it may be futile to try and remove sealer if it has tried to cure.

Share your postmortem findings.


HECAT: You support the Forum when you consider for your a/c parts.


58pacer on Fri September 05, 2008 8:32 PM User is offline

Here's the post mortem.

The new Ford dealer compressor is still free-turning...I haven't opened anything up yet because I wanted to wait until the weather cooled down a little, but the clutch seized completely yesterday, and forced my hand.

Turns out it appears the clutch failed in two stages. The first stage it got noisy and then seized up when energized. The solution was disconnect the pressure switch, and run without A/C until I got around to fixing it.

The second stage was clutch seized even when not engaged. When I took the clutch off the compressor, I found the bearing had turned into a pile of ball bearings and a lot of brown dust.

Got a new clutch today, but unfortunately I was not delicate removing the bearing inner race from the newly-installed compressor and I broke the compressor casting at the snap ring groove. Dumb, dumb, dumb.

So system is going to get opened up anyway to replace the forward case half of the compressor. I have a new shaft seal to go into the old compressor case half, so I'm hoping the new compressor will be as still be as good as new when I'm done swapping parts. I've already taken off the old compressor case half, and it's very simple. Trickiest thing will be getting that seal in neatly without damage.

But since the compressor appears to be mostly unscathed from all this, I think I may have gotten off easy. Time will tell if my first R134a conversion was an ultimate success.

Chick on Fri September 05, 2008 9:17 PM User is offlineView users profile

I would not waste my time tryimng to rebuild an FS 10 when you can get a NEW fs 10. They may look easy, but it's not the "best" compressor out there.. Just my opinion... You may be able to get a good "offshore" compresor for even less. e-mail the guys at as they aren't all bad. And if they have them, they will be quality..Hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

58pacer on Sat September 06, 2008 2:50 PM User is offline

Thanks for the advice, Chick.

If I were paying for the labor and had very little personal time for DIY auto repair, I'd heed what you suggest.

However, I'm retired and regard any mistakes I make and the things I have to do to fix them as valuable experience. I'm getting real good at getting to the compressor on this car. When I first looked at where it was located, wedged into the corner of the engine compartment under the power steering pump, I seriously considered hiring the work out.

Anyhow, since this new compressor I put in a couple months ago is a new, genuine Ford part, and the only problem is the cracked nose, I took the risk pulling the compressor case front half off and replacing it with the one from my old core with a new seal installed.

To get the seal in, I fashioned a seal protector sleeve out of .005" brass shim stock, oiled it up and it slid right into place. I also got the new clutch installed (shimmed it properly per instructions), I've pulled an initial vacuum, and it's held for 30 minutes, so preliminary checks show everything's good so far.

I'm going to pull vacuum for about an hour now, then shut the pump off and watch the vacuum level through the day before I bolt everything back together so the car can be driven.

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.