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That works too. Although I can't see throwing parts at something. Put a can of refridgerant with a leak detector in it, for a couple of buck and a U/V light find out where the leak is. It could be the hoses. Or a fitting. One doesn't need a engine to fail on an airplane at 10,000ft but whats the worst that happens if your engine on a car fails? You end up on the shoulder of the highway?
Usually there is some warning of engine failure also, knocking, excessive smoke, etc.........
I am going to drive my truck for a total of 45 years, or until I am 90. Unless I wreck it.
No one ever drove a vehicle for 45 years while a piecework approach to repairs. In this case the air conditioning system quit on my 25 year old truck, so I am going to fix it so that it goes another 20 years.
Engine: The engine will not last 45 years. It is going to break. I can do a complete rebuild now, while the core is good, or I can break down in Wyoming during a blizzard. It's the same approach that truckers use.
Here's the story:
90 GMC 4X4. I bought it new; I am going to keep it.
Original compressor. Condensor replaced 10 years ago when I hit a deer. Original dryer.
I have had to recharge the system every year for the past few years, so something has been leaking during the winter, but not the summer. I charged it up 3 weeks ago and it did not hold the charge for even a few days. Worked fine for a few days.
This is a 25 year old compressor, so I am going to replace it. Dryer, too.
But I don't have a vacuum pump; no one has one to rent, either. I hate the thought of not pulling a hard vacuum on the system for a few hours after the work is done. But I don't want to spend 80$ on a pump I will use ONCE.
Anyone got any ideas on how I can do this? The only thing I have is a hand vacuum pump, and I'm wondering if there is a way I can use it.....?
Any comments from experienced AC people would be appreciated...
Diagnosing a problem by replacing expensive parts usually does no turn out well. Why don't you start by finding the leak?
You will NOT properly evacuate the system with a hand vacuum pump.
A vacuum pump that is not rated for microns and or used without a micron gage is useless. Your system must be evacuated to 500 microns and it must hold that vacuum to insure that moisture and non condensibles have been removed.
I am going to drive my truck for a total of 45 years, or until I am 90. Unless I wreck it.
No one ever drove a vehicle for 45 years while a piecework approach to repairs. In this case the air conditioning system quit on my 25 year old truck, so I am going to fix it so that it goes another 20 years.
Engine: The engine will not last 45 years. It is going to break. I can do a complete rebuild now, while the core is good, or I can break down in Wyoming during a blizzard. It's the same approach that truckers use.
You would be surprised what truckers do. I worked for a large trucking co. we had many vehicles with over 1 million miles that had never even had the valve covers off. I worked in a quarry where we had a chevy pickup truck with about 140K miles on it that they overheated and blew the head gaskets. The head mechanic decided he's rebuild the engine. I looked at it, saw there was NO ridge in the cylinders, the body was rotted away, the only reason it had plates on it was so they could run off property for coffee and said why bother?
Between unleaded fuels, and improvements in motor oils, you could get 500K miles out of a gasoline engine. Have you ever done an oil analysis on it? Some large fleets do that for scheduled maintenance. All cheaper than just throwing parts at it. It is your money though, do as you please.
Whatever you do, don't purchase a reman compressor! It will only last a summer or two. New is the way to go. You also may want to replace your high and low lines with the vehicle being 25yrs old. I had an issue with mine leaking on a GM car that I had. Unless they have changed, Autozone rents out vacuum pumps. I always rented one from them when I did A/C work on my car. But the last time I rented one, was back in 2012. Install new o-rings and lube them with a little bit of Vaseline if you're going to keep you same low/high side lines.
That information appears to be about large HVAC or refrigeration systems, whereas this discussion is about an automotive system.
The same principles apply, the same processes are occurring, system must be leak free, non-condensibles need to be removed, moisture must be removed.
The ability to hold 500 microns indicates a dry leak free system. The ebay vacuum pump linked does not even claim to be able to reach the vacuums need for hvacr service. Any air, any leak, any moisture will impact system life. Modern systems are very highly stressed, what worked on a 1970 mustang will kill one of todays system in short order.
Whatever you do, don't purchase a reman compressor! It will only last a summer or two. New is the way to go. You also may want to replace your high and low lines with the vehicle being 25yrs old. I had an issue with mine leaking on a GM car that I had. Unless they have changed, Autozone rents out vacuum pumps. I always rented one from them when I did A/C work on my car. But the last time I rented one, was back in 2012. Install new o-rings and lube them with a little bit of Vaseline if you're going to keep you same low/high side lines.
I wouldn't use Vaseline, that's petroleum based, refrigerant oil.
Quote:
Originally Posted by hevysrf
The same principles apply, the same processes are occurring, system must be leak free, non-condensibles need to be removed, moisture must be removed.
The ability to hold 500 microns indicates a dry leak free system. The ebay vacuum pump linked does not even claim to be able to reach the vacuums need for hvacr service. Any air, any leak, any moisture will impact system life. Modern systems are very highly stressed, what worked on a 1970 mustang will kill one of todays system in short order.
I always uses Hg, that vacuum pump on ebay had no problems pulling down 30" when I used it. That's the vacuum my gauges read, not microns. What's the equivalent in microns of 30"hg?
Whatever you do, don't purchase a reman compressor! It will only last a summer or two. New is the way to go. You also may want to replace your high and low lines with the vehicle being 25yrs old. I had an issue with mine leaking on a GM car that I had. Unless they have changed, Autozone rents out vacuum pumps. I always rented one from them when I did A/C work on my car. But the last time I rented one, was back in 2012. Install new o-rings and lube them with a little bit of Vaseline if you're going to keep you same low/high side lines.
I wouldn't use Vaseline, that's petroleum based, refrigerant oil. As far as a reman goes, that's a crap shoot. Some remans are good, some not so good.
Quote:
Originally Posted by hevysrf
The same principles apply, the same processes are occurring, system must be leak free, non-condensibles need to be removed, moisture must be removed.
The ability to hold 500 microns indicates a dry leak free system. The ebay vacuum pump linked does not even claim to be able to reach the vacuums need for hvacr service. Any air, any leak, any moisture will impact system life. Modern systems are very highly stressed, what worked on a 1970 mustang will kill one of todays system in short order.
I always uses Hg, that vacuum pump on ebay had no problems pulling down 30" when I used it. That's the vacuum my gauges read, not microns. What's the equivalent in microns of 30"hg?
The same principles apply, the same processes are occurring, system must be leak free, non-condensibles need to be removed, moisture must be removed.
The ability to hold 500 microns indicates a dry leak free system. The ebay vacuum pump linked does not even claim to be able to reach the vacuums need for hvacr service. Any air, any leak, any moisture will impact system life. Modern systems are very highly stressed, what worked on a 1970 mustang will kill one of todays system in short order.
This is hogwash especially for an auto ac system.
For starters a new drier will catch all the moisture in an improperly vacuumed system.
I ran a car that had to be recharged every year because of a leaky evap for around eight years recharging it every year, never once vacuuming it out.
Replaced the evap and drier and pulled a vacuum using one of those $15 air powered venturi ones, been three years now, car still has it's original 21 year old compressor.
The guys car is a 1990, nothing like a modern day system.
OP, if you have an air compressor grab one of those air powered ones from Harbor Freight. You'll also need the $45 gauge set, a can tap, and most likely two cans of refrigerant (I assume 134a?). Get the compressor oil that is correct for your compressor, as they sell several different weights. Definitely replace all seals, as they are fairly cheap. I would diagnose the leak first as if it's the evaporator those are a pain to get to.
I wouldn't use Vaseline, that's petroleum based, refrigerant oil. As far as a reman goes, that's a crap shoot. Some remans are good, some not so good.
I always uses Hg, that vacuum pump on ebay had no problems pulling down 30" when I used it. That's the vacuum my gauges read, not microns. What's the equivalent in microns of 30"hg?
You're fine. Let it sit and cap it off to make sure it holds the vacuum. Then suck it again as the moisture boils off. It's not rocket science. Be careful, when introducing the refrigerant into the system bleed the line of air first by cracking the yellow hose at the manifold with the can tap open.
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