Fix the A/C Myself or I'm I better off just paying a professional

[vipersinu2]

make this job simple and easy and cheap!

1st, find leak and repair
2nd replace accumulator
3rd fill up with 134a and bleed from high side untill freon comes out.

it's a no brainer my 97 with 198,000 is working good now for 3 years and I live in florida a/c is on all year round

I used no special tools other than the ford flange tool to remove the accumulator

 

[sehaare]

Back to square one.

After reading through those links last night I realized that I had been looking at the wrong scale on the gauges. I had mistakenly looked at the scale that said R143A thinking that was showing pressure and in fact is wasn't. So redoing the tests this morning here are the new correct numbers.


Ambient temp 88 degreess

Initial pressures with engine and A/C off

Low side 43# High side 45#

Pressures with A/C in Max and given time to steady out.

Low pressure cycles from 63# with compressor stopped to 22# at the end of the compressor run.

High pressure cycles from 75# to 100# at the same time

The Compressor is running for about 1.75 seconds and is off for about 7.5 seconds

So with those numbers I have a lot more refrigerant in there than I thought. It appears to me that the compressor is still tripping off due to the low side pressure decreasing to below the 30# setpoint and this is preventing the discharge pressure from going up any further.

So I guess the question is why? Should I be starting out with more refrigerant in the system or is there partial blockage in the system somewhere causing the compressor to suck the low side pressure down

Experts?

And sorry about the rookie mistake causing the first numbers to be bad.

Thanks Again
Steve

 

[RomeovilleIL]

Dumb question of the day -- is the system under the hood getting & staying cold when all of this is running (regardless the cycling times for now), or do components all feel hot or go hot-to-cold-to-hot as it runs?

Not concerned with what happens inside the cab at this juncture.

 

[sehaare]

Dumb question of the day -- is the system under the hood getting & staying cold when all of this is running (regardless the cycling times for now), or do components all feel hot or go hot-to-cold-to-hot as it runs?

Not concerned with what happens inside the cab at this juncture.

Heading out the door to work right now but the quick answer is nothing under the hood is cold.

Steve

 

[scucci]

With an ambient temp of 88, your static pressures should be at or above 100 psi as per pressure temp chart. You are short cycling because of low refrigerant charge. It is difficult to use static pressures to make any kind of determination other than the presence of some refrigerant. The normal high side pressure should be in the range of 2.2 times the ambient temp around the condenser, appr. 190 psi. It would be best to find the leak, fix it, apply a vacuum of at least 29.9 in.Hg. for 1/2 hour or more and charge the system with the correct amount of refrigerant.

 

[sehaare]

Thanks again for the help guys, I think that i'm getting close now. I'm sure that as a start the accumulator needs to be replaced. It is very rusty and it appears to be oily under it. I assume that is from oil leaking out with the refrigerant. I'll have to look at that more closely

This brings up a few oil questions.

First there was a recommendation to measure the the amount of oil in the old accumulator and then add that to the new system but in this case if the oil is leaking out of the accumulator then it would no longer have the proper amount in it. There is a sticker under the hood that list the weight of oil for the system should I just put that amount it? Can too much oil damage the system?

Also I was told to use PAG oil when I check the local autoparts store I found that their are multiple viscosities for PAG. Which one of these should I be using?

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/category_Tools-and-Garage_-49997326___#storeId=10151&langId=-1&catalogId=10051&sortBy=2&categoryId=-49997326&searchTerm=&pageId=ajaxPartList&category=&keywords=Tools-and-Garage&l1_categoryId=-49997326&l2_categoryId=&partType=&facetFields=mfrName_exact%2CpriceBucket%2Cclearance%2Csale%2C%2C&beginIndex=0&filterValue=l2_category%3A%22Tools+and+Garage*Air+Conditioning+Chemicals%22%7CTools+and+Garage*Air+Conditioning+Chemicals&filterValue=part_type%3A%22Tools+and+Garage*Air+Conditioning+Chemicals*A%2FC+Lubricants%22%7CTools+and+Garage*Air+Conditioning+Chemicals*A%2FC+Lubricants&pageSize=10&filters=l2_category%3ATools+and+Garage*Air+Conditioning+Chemicals%2Cpart_type%3ATools+and+Garage*Air+Conditioning+Chemicals*A%2FC+Lubricants&selectedPartNumber=&qty=1&ship2HomeClicked=

Thanks again, I'm learning a lot, I might end up trying to fix the A/C on a couple of old VW's that I have.
Steve

 

[joecrna]

As long as liqued stays out of the compressor, too much oil will simply decrease efficiency. If any liqued gets into the compressor, well, fluid is not compressible as such and something has to give.

Oil under the accumulator should first be traced; accumulator hole, bad O rings at fittings, and/or shraeder valves. My bet is O rings, you still need to replace the accumulator as this system has been open (leaking) for some time. The consequence is humidity in the system which leads to rust/corrosion and parts failures down the road. I always replace the shraeder valves unless its just a simple charge. Amount of oil to replace, now thats a guess. It hides in the evaporator, accumulator and condensor. Are you charging with straight 134a or an oil mix. If its from a normal parts store its likely it has some oil in it.

As for your pressures, you are still low. This I bet is what is leading to the frequent cycling. Static pressures are notoriously poor indicators but for your system 80-105 psi on both sides is more like it. All we really care about is when the compressor is running. At 88 ambient I'd shoot for 35-45 low side and 200-350 high side. I am more concerned with the low side until we know we are searching for a furhter problem.

1) Find oil leak and fix part/O ring/valves.
2) Pump sytem down- 30 mmHg or better for 20 minutes. If vaccum decreases, that was water actually vaporizing. If it falls a little one or two quick times, you still have a leak. Keep looking for it. Now pull a full vaccum again and let sit 30-45 minutes, the longer the better. If the vaccum doesn't hold, consider another leak.
3) Fill with 134a and oil using the directions with your gauges. Its best to actually weigh the freon. Part way through, introduce the oil (amount you decided to use). I usually split this into a few seperate amounts. Then finish the freon.

That's the long but fairly correct way. How are you going to pull a vaccum? You could just add more freon until the low pressure side is about 40 psi while the compressor is cycled on. Then see what happens. I tend to error on the overkill side myself but it's up to you.

 

[Lube]

I tend to error on the overkill side myself but it's up to you.

Nothing overkill about doing it the right way!

 

[sehaare]

anyone know which viscosity of Pag oil I should use?

 

[sehaare]

anyone know which viscosity of Pag oil I should use?

found the answer on a web site

EXPLORER
95-09 PAG46 GPL-5

 

[Benji-Man]

The HF cheap pump is all I have ever used, and has served me well. I've done approx. 30 vehicles for friends and family, with a lot of happy customers. A few don't want to spend the money for new valves/parts needed they feel, their car isn't worth it.

You Tube has a few good video's that walk you through how to evacuate, vacuum, and re-charge. They will show you what you're looking for and trying to achieve.

 

[sehaare]

The HF cheap pump is all I have ever used, and has served me well. I've done approx. 30 vehicles for friends and family, with a lot of happy customers. A few don't want to spend the money for new valves/parts needed they feel, their car isn't worth it.

You Tube has a few good video's that walk you through how to evacuate, vacuum, and re-charge. They will show you what you're looking for and trying to achieve.

I think that i've pretty much decided to at least start out with the HF Cheap pump first and see how that turns out (10 Min from HF store so if it doesn't work I can return it and get the more expensive one) and from what you say it should be OK.

I'll be checking out the you tube vids now thanks

Steve

 

[sehaare]

UPDATE

I hate when people ask a lot of questions and then go away without ever posting if it fixed the issue,

So here is how mine turned out - due to a lot of help here and a lot of reading I now have cold air

I'm not 100% sure that it is a permanent fix but it works good for now.

Here is what I found (turns out that I had two issues).

First the accumulator was covered with oil and obviously the source of the leak so I replaced that. The new one came with new o-rings and shrader valve so I used them.

I had also bought new schrader valves and additional o-ring to replace the high pressure side valve and any leaks that I found. That's were I ran into a few problem. Apparently the HP side scharder is larger than normal so the new valve was to small (same size as LP side) so I had to just tighen the old one. The 0-rings didn't really match up will with the installed rings (typically the new rings were thinner) so since the old ones were in good shape I oiled them and reused them.

I also went in and replace the air orifice tube and it was a good thing that I did. It was completely plugged with what looked like a combination of stop leak and and what I believe was descant.

That was why the pressure was dropping so fast every time the compressor kicked in which then immediately trip it off then on low pressure.

So I blew out the condenser, the evaporator and the hoses with the compressor disconnected. I got a lot of crap to blow out.

I then went ahead and replace the orifice.

I put 4 ounces of PAG 46 into the accumulator (full system spec was 7, I saw recommendations of 2-3 for the accumulator but figured that it had leaked quiet a bit, but that I had also added some when charging freon so 4 seemed about right).

I drew a vacuum with the $100 Harbor Freight electric vacuum pump, I tried the air powered one but couldn't get above 24 inches of vacuum so I took it back and got the other pump. I was able to get 30 inches of vacuum and after I sucked it down a few times to get all of the water vapor out. It held like a champ.

Charge din 30 onces of R-134A and everything is running smoothly and cold.

Final pressure values at around 80 -85 F were 42# on LP and 200 on HP. Which fall right into the curves in the explore manual.

My one fear is that I didn't flush out the system well enough and that the screen on the orifice tube is going to plug again but If I have to go in again at least now I have all the tools.

PS those spring fittings suck.

Thanks Again for all the help
Steve

 

[drdoom]

Thanks for posting the outcome, so many threads are never closed. Good job.

 

[joecrna]

Really, thanks for posting the outcome, so few do. By the way, what led you to inspect the orfice tube. I wouldn't have looked to that until it was back together and still misbehaving.

 

[drdoom]

O-Tube

An orifice tube typically sells for less than two dollars, and should always be replaced when the system is opened.