BAC Forum
General Boards => Technical Support => Topic started by: Fred Cook on September 19, 2018, 12:14:01 PM
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My AC compressor froze up and busted my serpentine belt. We are currently stranded 100 miles away from home at a friend’s house. I want to replace it myself. Is there a way to do this without losing all my R134?
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You can not replace the compressor without first evacuating the refrigerant.
However, if you only need to replace the pulley/clutch assembly (i.e the parts in the pic below), you can do that without removing the compressor and disconnecting any lines.
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You can not replace the compressor without first evacuating the refrigerant.
However, if you only need to replace the pulley/clutch assembly (i.e the parts in the pic below), you can do that without removing the compressor and disconnecting any lines.
Thanks for the info. Looks like I will have to drain the lines. I suppose it will be OK to operate the unit without any R134 in it until later. Is that correct?
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We have replaced our compressor 3 times on our 2004 Marquis and each time I believe we had to because of low refrigerant is why it burned up. Looked at doing just the clutch repair but due to relative cost just decided to do it with new compressor and try to figure out why loosing refrigerant. Actually I do not know or believe if you can ever get the dash air right on a coach as we spent a lot of $$$$ trying to.
Someone with more expertise on A/C than I can comment but I believe that loss of refrigerant is why the compressor burns up. I am not sure if when you start to not get cold air you can leave it turned off and get more refrigerant added so you do not burn up compressor. Comments please .
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Napa Auto/Truck stocks the compressor assy. Clutch assy would have to be ordered. Compressor comes filled with oil. 2 coolant lines, 4 bolts, disconnect clutch wires, and belt is probably gone. Pump is $300 and belt about $35. Leave clutch disconnected until recharging.
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Gentleman, AC compressor lock up can occur from over filling coolant to system without vacuum AC
System than recharging system. Many will cap off cooling system with these little cans of coolant.
There is a few factors that come into play between the high pressure and low pressure along with compressor. Dave Atherton Retired Cat Mechanic
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Thanks for the info. Looks like I will have to drain the lines. I suppose it will be OK to operate the unit without any R134 in it until later. Is that correct?
The unit will not operate without refrigerant in it, of course.
It is okay to leave the compressor in place and drive the coach. I believe you said the belt broke from the compressor pulley seizing. If this is the case you can just leave the belt off - as long as that belt does not also turn other things (like the Alternator and/or water pump). I don't recall what engine you have (and I cant look until finish this post).
One of the reasons these AC compressor replacement jobs fail, is that when the system leaks refrigerant "oil" is lost. It is impossible to know how much oil was lost. Most shops doing a quick repair (i.e. replacing a hose or such) will add some oil back into the system during a recharge, but if too much oil is added the system won't cool properly, and if too little oil is added the compressor burns up (in a short time).
The proper way is to drain all the oil out (either remove the compressor, evaporator, condenser, and receiver/drier and drain - or flush everything thoroughly) then add in the correct amount of oil, putting some in each component). Also, note that a replacement compressor will typically come with oil in it - but that doesn't mean the entire system will have the correct amount of oil after the compressor is installed.
The other challenge in doing AC work on these coaches, is that the "universal AC charge guides" don't have a listing for a Beaver (Monaco, etc.) so the shop doesn't know (can't look up) what the correct amount oil is - or the correct amount of refrigerant to add. If there is a decal with this info on the evaporator housing - you're lucky but many times this decal is gone or ineligible due to age. Fortunately the Owners Manual has this info (at least mine does) and although general it is still useful if that decal is gone. Note how much additional (over a typical truck or car AC system) oil is needed due the 80+ feet of AC hose used on these coaches.
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Mike,
On the 05, where are the high and low side ports, front or rear of the coach? Pressure readings will differ so curious to know where 200PSI is read.
Steve
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On the '05 the ports are located at the compressor (about 6 inches away from the compressor on the AC lines).
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The last time I had a shop do a check for leaks, and a re-charge, they called Monaco and asked them how many lbs. (?) of refrigerant was max. IIRC it was 4-1/2 or 5.
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Fred,
You do not need a serpentine belt to drive a C 12 as long as you keep the generator running to charge your batteries. If you are using the Echo Charger system, you will have to hold down the boost switch periodically or run a jumper from the house battery positive cable to the chassis battery positive cable because your coach will use more than the 15 amps that it can supply to the chassis batteries.
In the 175,000 miles that I drove my 2000 Marquis, I had 2 A/C compressor failures and one idler pulley bearing failure that resulted broken serpentine belts. So I just cranked the Onan and keep driving. The C 12 powers all necessary components from the timing gears except the alternator, so as long as you can charge your batteries, you do not need the serpentine belt.
Gerald
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Fred,
You do not need a serpentine belt to drive a C 12 as long as you keep the generator running to charge your batteries. If you are using the Echo Charger system, you will have to hold down the boost switch periodically or run a jumper from the house battery positive cable to the chassis battery positive cable because your coach will use more than the 15 amps that it can supply to the chassis batteries.
In the 175,000 miles that I drove my 2000 Marquis, I had 2 A/C compressor failures and one idler pulley bearing failure that resulted broken serpentine belts. So I just cranked the Onan and keep driving. The C 12 powers all necessary components from the timing gears except the alternator, so as long as you can charge your batteries, you do not need the serpentine belt.
Gerald
This is great information Gerald. It’s nice to have a coach that will not cause serious damage when a belt pops off.
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Fred
Strongly recommend that you make sure your replacement compressor is Sanden U.S built compressor. The Sanden TYPE or Sanden LIKE are not from Sanden. The Type and Like are Chinese knockoffs.
Had mine replaced and had to Insist on Sanden U.S. built out of Texas.
Do not buy it from a coach supplier, very expensive. A/C Parts Warehouse have the U.S. built for $289.00. Same compressor from Monaco was close to $900.00
For what it's worth
Larry D.
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Fred
Strongly recommend that you make sure your replacement compressor is Sanden U.S built compressor. The Sanden TYPE or Sanden LIKE are not from Sanden. The Type and Like are Chinese knockoffs.
Had mine replaced and had to Insist on Sanden U.S. built out of Texas.
Do not buy it from a coach supplier, very expensive. A/C Parts Warehouse have the U.S. built for $289.00. Same compressor from Monaco was close to $900.00
For what it's worth
Larry D.
Thanks Larry. The brand name on my ordered compressor is Seltec. I paid $331 which included 2 day shipping. Picking it up tomorrow. Don’t know much about it.... is that a good compressor?
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Are you planning to just replace the compressor, or do you have other parts too (like the Receiver-Drier).
Are you going to flush the system?
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Are you planning to just replace the compressor, or do you have other parts too (like the Receiver-Drier).
Are you going to flush the system?
I have looked everywhere for the receiver dryer and cannot locate it. All I see are two lines coming off the compressor one with a blue cap one with a red cap. The two lines go forward and disappear past the transmission. I see one line up front that goes into a small radiator. Where can this dryer be located?
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Fred, on my '05, the AC Condenser is located just behind the front bumper (if you can call that fiberglass a bumper). The Condenser has the electric fan mounted to it, and on its right side is the Receiver-Drier. The expansion valve is above the generator coming off the housing that holds the Evaporator. So everything is up front except the (engine mounted) Compressor.
The first and last photo are taken laying on the ground under the electric bay, and the middle photo is with the generator slide out and camera pointing up toward windshield/dash.
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Fred, on my '05, the AC Condenser is located just behind the front bumper (if you can call that fiberglass a bumper). The Condenser has the electric fan mounted to it, and on its right side is the Receiver-Drier. The expansion valve is above the generator coming off the housing that holds the Evaporator. So everything is up front except the (engine mounted) Compressor.
The first and last photo are taken laying on the ground under the electric bay, and the middle photo is with the generator slide out and camera pointing up toward windshield/dash.
Great info Mike. Believe I will be able to find it now.
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Fred,
Do you have all the equipment to properly replace a compressor? Vacuum Pump, Manifold Set and how are you going to recover the freon in your system? If you're going to open up the whole system I would suggest a cylinder of Nitrogen to pressure test the system after you change all the parts and to purge out the air/moisture. Also a 30 lbs can of freon, using the little cans is a sure way to get a bunch of air in the system and you will be back to where you started very shortly.
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Hi Fred,
About 4 years ago, our dash AC went south. First try at having it repaired at a shop was not successful.
After returning from from the next trip with the Generator and roof Air on all the way home. It went back to the shop.
This time we got the right Technician for the job.
It turned out the Dryer failed and sent little glass bee bees through out the system, so they had to blow out 40' of lines from the compressor to the condenser. The Condenser required cleaning along with new compressor and dryer.
Needless to say it was a costly repair.
It is worth it to take it to a shop that understands our coach's A/C system, experience and knowledge is definitely worth the price.
Good Luck,
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Hi Fred,
You have gotten really solid advice on here. Always replace the drier any time the system is opened up. If you think there is contamination or the refrigerant has a burnt smell you want to flush the system. Absolutely nitrogen charge, carefully so you don't blow one of the rubber lines (voice of experience) ha and while you have it charged with nitrogen, soap bubble all fittings. best to leave it charged over night and check your pressures again to be sure you don't have a leak. You will have a slight variation due to temperature change. Evacuate and recharge according manufacturer specs. I don't know if the manufacturers weigh in the charge when having that long of a lineset to the front. If they do then weigh in the correct amount. Also as said before don't waste your money on small cans and find someone with an epa license to hook you up a jug of 134A. Yes, I do HVAC and have a slight idea about this.... slight... as I get older I find I know less than I thought I did.
This another thought I had after reading all the posts. I not trying to hijack the thread and if out of line I' sorry, still kinda new here. With the AC being driven off the engine with a hundred feet of hose, has anybody ever thought of using a compressor like the ones for the back of suburbans to run the dash air? Just a thought. No long line sets, less refrigerant, not engine driven so if it seizes it won't burn a belt off. Again, If i was out of line here I won't be offended if it gets deleted.
Good luck on your AC
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An electric (12VDC) AC compressor is an option. They are not cheap and require around 30A to 50A (depending on size) to operate, but it may be a good choice for someone with a bad compressor and 80+ feet of bad AC hose (and where the hose very difficult to access/replace) - and where all the rest of the AC components are up front.
https://www.seanhylandmotorsport.com/SHM-electric-air-conditioning-compressor-3753
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Fred,
Do you have all the equipment to properly replace a compressor? Vacuum Pump, Manifold Set and how are you going to recover the freon in your system? If you're going to open up the whole system I would suggest a cylinder of Nitrogen to pressure test the system after you change all the parts and to purge out the air/moisture. Also a 30 lbs can of freon, using the little cans is a sure way to get a bunch of air in the system and you will be back to where you started very shortly.
No, I do not have the equipment to get the job done no the expertise. Looks like it may be a major expense. I hope to find a decent place somewhere around St Louis.
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Fred,
Be sure to verify that the compressor did seize and not just the pulley seized.
If the compressor seized you will need to flush the system and replace the receiver-drier along with the compressor. But if it was just the pulley (the parts shown in my first post) you can just replace those and not need to touch the rest of the system. No need to evacuate the refrigerant to replace just the pulley/clutch assembly.
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Fred, on my '05, the AC Condenser is located just behind the front bumper (if you can call that fiberglass a bumper). The Condenser has the electric fan mounted to it, and on its right side is the Receiver-Drier. The expansion valve is above the generator coming off the housing that holds the Evaporator. So everything is up front except the (engine mounted) Compressor.
The first and last photo are taken laying on the ground under the electric bay, and the middle photo is with the generator slide out and camera pointing up toward windshield/dash.
Mike, I have reviewed your photos, crawled underneath the front end of my coach and have looked everywhere. I have located the condenser with fan and looked all around it. I see hoses coming out/in but there is no receiver dryer anywhere to be seen. I traced the lines back until they disappear both in the front and back and no dryer anywhere. Could it be my coach does not have a receiver dryer?
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Fred, it has to have a Receiver-Drier somewhere. That's an important component used for removing any left over moisture in the system and to separate/catch the liquid refrigerant from the gas.
I don't know where it is located on the 2002 Patriot. Did you located the expansion valve at the evaporator housing? I may be next to expansion valve. It has to be located somewhere between the condenser and the expansion valve (the high pressure side).
https://macsworldwide.wordpress.com/2010/10/13/what-is-a-receiver-drier/
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Fred,
Do you have all the equipment to properly replace a compressor? Vacuum Pump, Manifold Set and how are you going to recover the freon in your system? If you're going to open up the whole system I would suggest a cylinder of Nitrogen to pressure test the system after you change all the parts and to purge out the air/moisture. Also a 30 lbs can of freon, using the little cans is a sure way to get a bunch of air in the system and you will be back to where you started very shortly.
No, I do not have the equipment to get the job done no the expertise. Looks like it may be a major expense. I hope to find a decent place somewhere around St Louis.
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Too bad you're not close around Wickenburg, Az you could come over here and we would knock out the replacement in no time, replaced my compressor last spring.