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89 chev c1500

nz chev on Wed November 05, 2008 4:38 AM User is offline

Year: 1989
Make: chev
Model: c1500
Engine Size: 5.7
Refrigerant Type: r12?
Country of Origin: New Zealand

hi i have purchased the following replacement parts for my truck compressor, accumulator , evaporator, orifice tube and are looking at leaving the condenser in place. how much oil and gas do i need to put in this system and can i use r134a when i re-gas it? do i put the oil in first then vacuum the system then add the gas?

dasinc on Wed November 05, 2008 2:20 PM User is offlineView users profile

Hello,

It wouldn't be a bad idea to flush the condenser to get the remaining mineral oil and debris out of it. The system oil capacity is 6-7 ounces. If you are converting to R-134a I would use PAG150 oil. The refrigerant capacity for your vehicle is 52 ounces of R-12, but when you convert to R134a you use 87% of that amount or 45 ounces. I would spread the oil when putting it in as follows. 3 ounces in the compressor, 2 ounces in the accumulator, 1 ounce in the evap and 1 in the condenser. Foe ease, put in the oil before mounting the components. After everything is installed pull a good vacuum, at least a half an hour, and then charge the system.

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Take care,

Travis

tpestes@dealerautomotive.com

nz chev on Wed November 05, 2008 9:28 PM User is offline

hi travis thanks for the help can i flush the condenser with an air compressor or should i use something else?

iceman2555 on Wed November 05, 2008 10:25 PM User is offlineView users profile

A even more efficient method to lube the system is to simply add 3-4 oz into the compressor suction port. Add the remaining lube to the inlet of the accumulator. This lube in the accumulator will insure lube flow to the compressor at initial engagement and during the recharge process. It is possible to damage or destroy a compressor during the recharge method if there is insufficient lube in the accumulator. This takes into consideration that the system is being charged with small cans instead of using a recharge machine.
The amount of refrigerant to convert a system has long been a 'subject' of much debate. A good method to insure complete recharge is to use the delta temp between the evap inlet and evap outlet.
Try this, MAX COOL (REC), HIGH BLOWER SPEED, DOORS OPEN, ENGINE @ IDLE. Charge until the inlet and outlet temps are the same or within 3-5 degrees of each other. This will insure 'flooding' of the evap under a high heat load and will insure correct lubricant flow to maintain the compressor. A system that is undercharged will soon suffer compressor damage due to lack of migration of the lubricant.
Since a lube recharge comes in a 8 oz can...simply use the entire amount. The extra...if there is any...will not harm the system and may prevent future problems.
Insure that the fan clutch and other engine cooling components are functioning as they should. Esp the fan clutch.
Good luck.

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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

mk378 on Thu November 06, 2008 8:54 AM User is offline

If R-12 is still legal in your country, you should consider using it. Many people have reported that R-134a didn't work nearly as well in these trucks. If there's a possibilty you'll be running R-12 now or in the future, don't put any PAG oil in. Use ester oil instead. PAG reacts with R-12 so it would all have to be completely removed before R-12 could be used.

After a compressor has failed internally and put debris in the condenser, you could be better off replacing the condenser than trying to clean it. When replacing the condenser, note that it is possible to hook it up backwards. The line from the compressor must go to the top of the condenser.

Especially with R-134a, the fan clutch needs to be working well to get good performance. When they get old they don't spin the fan as fast as it should. Also the fan shrouds must be in place and the air passages clear. Even if you're keeping the old condenser, while the system is empty consider pullling the condenser anyway to clean the air passages in it and the radiator.

iceman2555 on Thu November 06, 2008 9:42 AM User is offlineView users profile

Revision to agree with mk378, overlooked the New Zealand part. If 12 is available and legal to purchase, by all means stay with 12, performance should be much better. However, the method to recharge stands as a good method to determine refill charge even if 12 is used in the system.
Good luck!!!

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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

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