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Seized AC compressor

warrenpfo

Well-Known Member
Joined
Jul 21, 2010
Messages
2,895
To start what I know about AC can be put down on the back of a match box.

My AC has never worked since I bought the car with the salesman telling me it needed re gassing. Now i know ac should not ever need re gassing as its a sealed unit so if you loosing gas you have a leak.

My assumption was that it was going to me a hole in one of the pipes as usual and would then have to get it replaced. So off to the AC man i went this morning to get the system checked out and on arrival he tried to turn the AC compressor and tells me that it is seized.

http://www.youtube.com/watch?v=CgiDopwCCrM

So i have sourced a new one that is the same model but has a different head on it and pulley that i will need to swap over.

I will update as soon as i know whats happening
 
Unfortunately it has probably been used with low or no gas left in it, which then damages the compressor. I'm sure ive been told before that the gas lubes the compressor but i might be wrong. i had dye put through my ac and showed a hole in one if the pipes( it had been rubbing on the bodywork and worn through) so replaced and realigned and all has been good the last four years.
 
Hi Warren

The comp you show does not look seized to me. If the seized one is not the one on the video try turning it robustly. It could just be lack of use and just a little seized. The oil is dissolved in the gas so when the gas goes the oil goes. HOWEVER there is a low pressure switch which stops the comp coming on when the pressure gets low. If you have a rear evaporator, evidenced by rear passenger controls as well as the driver's, the pipes running to the back may be corroded. They are vulnerable.

There is also a fusible plug on the top plate of the comp so even if it gets hot the plug will melt and let all the gas out on purpose to let the low pressure switch disconnect the drive.

The comp is driven by the v belt. The v pulley is connected by a electric/magnetic clutch to the drive shaft.

If there is an old drive belt on you may well not have a seized comp as it would have burned the old belt up.

Frank
 
Hey Frank

The video is not of my comp but it shows how you should be able to turn it with ease. Mine on the other hand does not turn at all like the one in the video and on putting a 10mm socket on it i could not get it to budge. I will give it a go with a longer bar as the radiator and other bits where in the way but i did give it a good go.

I also thought that the belt would be burnt out but that is not the case at all as it just spins with the magnetic clutch not engaged. I was thinking of trying to "force" the clutch to engage and see if the force of the belt might get it to spin but will see how i go with a cheater bar.

I know about the rear ac unit and pipes as i had the pipes on my last one replaced.

I was also told by an ac guy a few years back that the compressor should have a sensor on it that means it will not engage if its low on "oil" and so should still be ok but im not sure how true that is.

Im off out side to put a longer bar on it.

UPDATE:

Even with a 20" bar it wont budge and im concerned i might just snap the head of the 10mm bolt and then its a whole another story.

Further update:

The clutch on the pulley is working as i wired it direct to the battery. What damage am going to do by engaging the clutch with the belt spinning with what appears to be a seized compressor if only for a second or two.
 
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Don't know Warren but the engine will not stall. So something will give. Maybe just a bit of smoke; or damage to the comp clutch. I don't think you will hurt the car itself.

Frank
 
After today's drive around the M25 its time to pull my finger out and sort this out.

Toyota want silly money which i am not parting with and as it happens the Denso compressor (denso 10pa17c) used is quite common. My thinking is either get this one and change over the clutch and pulley along with the "head" which is where the pipes bolt too. The one in the picture has a plate over where the head goes. I can get this one for £175 + $17 for a seal kit to replace the head.
http://www.ebay.co.uk/itm/AIRCON-CO...arts_Vehicles_CarParts_SM&hash=item338311bbb0

Or

I could get this one all in for £300 maybe £275

http://www.ebay.co.uk/itm/TOYOTA-LA...arts_Vehicles_CarParts_SM&hash=item232ce96b85


Any thoughts.
 
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I have managed to negotiate the new one down to £250 and although more expensive than the other one its a fit and forget option so the route I am going to go.

The AC man said to also change the cartridge in the tube running down the side of the ac radiator. Does anyone know what this is called?
 
Probably a dryer - you're meant to change them if you break open the system.
 
That's it thanks.

Not cheap at £45 but I guess it needs doing.
 
I would strongly recommend flushing the system as well before you fit any new parts if the compressor is seized as you may have swarf in there.

Sent from my GT-I9100 using Tapatalk 2
 
Now that's a very good point Rob. There is no filter on the inlet side of the pump unless there is one in the pump itself. On the outlet the dryer is also a filter to protect the evaporator nozzle. Swarf from the pump should end up in this as that is the way the flow goes. But if the pump seizes and stops working it could spread swarf up either the inlet or outlet pipe.

Frank
 
The Denso pumps aren't usually too bad for swarf. You can do a simple check buy taking off the manifold and seeing if there's any around there. It can go back up the suction pipe because as the pressure equalizes across the pump, it get's sucked back up the inlet.

Don't bother trying to unseize the old pump on the car - it's seized! But you might want to check for the leak before you fit the new pump. Have someone pressurize it, or do it yourself with a can of refrigerant (but not one that contain magic ingredients - sealers, lubricants, performance enhancers etc.
 
Hey Dave you seem to know your stuff so thought I would ask. I have been told to make sure the compressor has oil on it before I start using it. How do I do this, is there a full plug that is used or a sight glass as I can't remember seeing one.
 
Sounds like Dave might be getting a few "visitors"

Gra.
 
There's a standard procedure for changing the compressor. There is no drain plug, so remove the old one and tip it on it's back so any oil can come out of the inlet and outlet. Measure the quantity that comes out, and check for debris. Twist and turn it to try and get the most out.

Do the same with the new one. Some new units come with a whole system qty of oil, some are empty. Either way, drain what you can, turning the shaft as well to expel any in the cylinders. Throw this oil away!

Buy some replacement oil - PAG ND 8/ISO46 viscosity.

Add back to the new compressor (through the ports) the same qty you got from the old one - plus 20ml for the new dryer, plus 20ml for good measure (assuming nothing else has been replaced or flushed).

Mount the new compressor, fix the lines, but make sure you turn the compressor by hand a good few times to expel any oil from the cylinders, otherwise it will hydraulic.

If the new compressor comes without a clutch, you can remount the old one. But you will need to reset the clutch gap, and this is done with shims behind the plate. So make sure you keep the old shims! Gap should be about 25 thou.
 
Dave it sounds like you are the man for the job. I take it you are not local to Berkshire.
 
Sorry for the double posts but I have not worked out how to edit on tapatalk.

Can I DIY flush the system or is it best done by a professional and I take it flushing the system is different to vacuuming the system.
 
Sorry, I'm in Sweden! Just updated my profile as it wasn't obvious.

I would check for debris first, as it's quite possible it's still clean. You may also wreck some of the joints trying to get it apart, and you can't flush the evaporator without taking it out of the dash. So that only really leaves the pipes and condensor. I doubt anyone has decent equipment to flush, as there are hardly any specialist around, simply people that have bought a machine, but claim to be specialists.

You can try this guy, an old friend/customer of mine - http://www.air-care-automotive.co.uk/, he is old school, and has a lot of equipment. He takes his time and extremely particular though! It may be you just get him to do the whole thing as he has oil, O rings etc.

Yes, flushing is different to vacuuming. TBH I used to avoid flushing where possible, as it takes time and money to do right, and can reveal more problems, like seized fittings and stripped threads.
 
Thanks a lot Dave you have been most helpful. Everyone I call makes a funny sucking sound on the end of the phone and then proceeds to tell me its about a 6 hour process to flush the system at a cost of around £500 which seems a bit excessive.

I will take a look at the head of the old compressor and make sure there is no debris and then go from there. I shall also give your man on the ground a call to discuss further.

EDIT: John sends his regards to you Dave and I am off to his this Saturday and we are going to piece it all together. I will keep you posted.
 
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