Clog in the Ac system...and question on recharge

[azscott]

Well I am not sure the compressor is shot....they said well it makes noise. I ahve heard noisy compressors and that does not sound noisy...sure when you turn on the AC I can hear it run but not noisy...maybe a slight bearing noise but dang...my 2044 Taurus sounds the same.

Now I know there is a plug in the system....so where would the most likely place be?

They quoted my actually $1400.00 to fix it...me thinks NOT.

So I had them evacuate the old R12...a total of 38 oz they pulled. So....would you be able to open the lines and blow out the lines.....if so...is there any components that would be harmed and should be bypassed from compressed air.

I might replace the valve and the drier and the expansion valve as they said this is where the clog was. Although I am sure how they know...I think it is a guess.

What are anyones thoughts......should it be fine to try and puge the system with compressed air to clear or find the plug. I don't mind the cost of the drier and expansion valve.....but would like to fix the obstruction first before dropping 4 bills on a compressor.

Scott

[5523Pathfinder]

Well, IMHO, I dont think you have a clog. The A/C system is a closed system and even if there is a leak, there is really no way something large enough could get inside to plug it. Now, if the system was open, thats a different story. The only possible place for a "clog" would be at the expansion valve on the evaporator. The expansion valve may have issues. Now for the rest of the system, you can blow the lines out with some compressed air. When you reattach everything then put a vaccum on the system, any oxygen or water will be boiled under the vacuum and will be gone.

A quick way to tell if the system is working right, is to just touch the lines. Once the system is properly filled, you should be able to touch the lines and find out if everything is working correctly. The refridgerant will be warm as it enters the expansion valve. The lines leaving the evaporator should be cool. The high pressure side from the compressor should be hot, but you should still be able to touch it. The coldest point of the system is after the expansion valve, but before the evaporator(its hard to touch being its inside of the evap box). If you have more questions, just ask!

 

Hope this helps

[azscott]

That is kinda what I was thinking. I think they just go to the easy fix....compressor/expansion valve and drier and then figure...well that should fix it.

I think I will order the valve and replace it and blow the system out. then take it to a different place to have it drawn down and charged. I don't have anyway to draw a vacuum on it myself.

A good question is....should you have it drawn under a vaccum as quickly as possible after blowing it out and reinstalling everything....would seem so as any moisture sitting around for any length of time would be bad!

Any options for an alternative to R12 besides R134 that will actually work. R12 is darn expensive especially to recharge an entire system that was drained?

I know there is freeze 12.....Autofrost and such. Just wish I could charge it myself....but if r12 is the only real option I will suck it up and have to pay the $140.00.

Thanks

Scott

[5523Pathfinder]

Well, the best thing is to replaced the evaporator and expansion valve together. I imagine they want to replace the the drier as a preventative step. Changing over to R134A is a bit trickier than just putting it in. Most of the time they want you to replace the compressor and the o-rings to work with the new refridgerant. IMHO, R12 is much better than R134A. You may want to shop around on the price for refilling. The right thing to have done is to have A/C dye installed with the recharge. This will allow you to look for leaks by yourself using a U/V or blacklight if any should come up later.

 

Yes, it is best to have the system evacuated as soon as possible to prevent any damage to the system. Keep your A/C and defroster off until you have it charged.

 

There are some options out there for recharging your system. I would stick with R12 and have it professionally installed if you do not know what you are doing. Some have used aftermarket refill systems with decent luck. Just be careful!

[adamzan]

Try looking for the red-tek 12a stuff. Simon and I have both used it in our trucks, it cools the same if not colder than r12. We haven't had any issues so far....

[mws]

The expansion valve would be the most likely place where a clog could occur - it is a small orifice.

 

And I'm not convinced about the diagnosis being a clog either.

 

And for the $1400 they were going to charge you, you could afford to get your own vacuum pump and do it yourself - assuming you understand how and are capable of doing it yourself.

[azscott]

Well what would cause a vacuum to be detected on the low pressure side.....a defective technician doing the diagnosis.....or?

Here is what I know is happening...the AC blows cold for maybe 5 minutes and then cycles from cold to warm. I can see how the temp sensor would shut it off (if there is one and they said there is)....if there is an obstruction?

Is there anything else to consider.

I just had a feeling they were shotgunning the diagnosis...replace it all and one of the parts SHOULD fix it.

Also...I figured for that money I could buy the vacuum pump, parts and all and still be ahead of the game.

Scott

[mws]

If I were in your shoes, I would be willing to pay for a second opinion.

[azscott]

I made an appointment with the dealer..which i was going to do originally but they are twice the distance....anyway they said they doubt it was a clog too. Probably a switch cycling the compressor on and off.

Thanks for all the help for now...we will see what they say. May still fix it myself but will let them troubleshoot it first.

 

Thanks

Edited July 30, 2008 by azscott

[msavides]

I made an appointment with the dealer..which i was going to do originally but they are twice the distance....anyway they said they doubt it was a clog too. Probably a switch cycling the compressor on and off.

Thanks for all the help for now...we will see what they say. May still fix it myself but will let them troubleshoot it first.

 

Thanks

 

 

He Azscott.

 

 

This is your problem. My old 1990 pathfinder was doing the same thing as yours, It can be thought of as a clogg. This thing has an orifice that opens and closes to let the freon into the evaporator. It has a temp probe that will open and close the orifice depending on the temperature in the evaporator. It is a bit of work to replace (have to pull the box) and you will have to discharge the entire system. I did the repair myself but then again I have a friend with all the equipment. At least Knowing how much the part costs will help you not get screwed on the repair.

 

http://www.autozone.com/R,1440377/vehicleI...oductDetail.htm

 

Mark

 

Edit: Just saw that mws suggested the same thing. Right on the money!!

 

another thing to take note of. If your evaporator is full of leaves (common problem) your evaporator will freeze up and cause the expansion valve to close down (this is normal operation for the expansion valve) due to limited air flow warming the evaporator. I noticed my evaporator was full of crap when I pulled the box to replace the valve.

Edited August 1, 2008 by msavides

[Alkorahil]

I made an appointment with the dealer..which i was going to do originally but they are twice the distance....anyway they said they doubt it was a clog too. Probably a switch cycling the compressor on and off.

Thanks for all the help for now...we will see what they say. May still fix it myself but will let them troubleshoot it first.

 

Thanks

 

 

Your Pathfinder AC system has 3 important sensors designed to shut the AC compressor off if it thinks there is a problem. This is done to protect the compressor and other parts of the AC system. The downside is that if one of these sensors is bad or going out or has a corroded/loose connection, the system thinks there is a fault and the system shuts down.

 

 

 

You have a temperature sensor on the compressor, on the top towards the back. If it senses the compressor is too hot or cold it will not let the compressor engage or turn it off.

 

There is a Pressure switch on the liquid tank could be bad, causing the system to shut down when the system has too much or too little freon.

 

There is also the tHermo sensor in the evaporator case that is designed to detact if the evaporator is freezing up.

[azscott]

Thanks to both of you for the reply's. I had started to think it was something along those lines which is why I did not let the knuckle monkey do any further work on it. Hey it only cost me $25.00 total for his work and in the end he evacuated all of the freon too so no big deal.

If I had the ability to recharge the system I would do the whole repair myself...but I don't. Obviously no R12...and I don't have any way to vac out the system once I open it up to replace parts.

If Nissan gives some outrageous quote i will do it myself....actually the srvice manager told me if was going to be expensive in parts and labor that he would let me know so I could do it myself and just bring it back in when done so they can refill the coolant. Which is fine as he was cheaper than the local idiot.

Scott

[azscott]

He Azscott.

This is your problem. My old 1990 pathfinder was doing the same thing as yours, It can be thought of as a clogg. This thing has an orifice that opens and closes to let the freon into the evaporator. It has a temp probe that will open and close the orifice depending on the temperature in the evaporator. It is a bit of work to replace (have to pull the box) and you will have to discharge the entire system. I did the repair myself but then again I have a friend with all the equipment. At least Knowing how much the part costs will help you not get screwed on the repair.

 

http://www.autozone.com/R,1440377/vehicleI...oductDetail.htm

 

Mark

 

Edit: Just saw that mws suggested the same thing. Right on the money!!

 

another thing to take note of. If your evaporator is full of leaves (common problem) your evaporator will freeze up and cause the expansion valve to close down (this is normal operation for the expansion valve) due to limited air flow warming the evaporator. I noticed my evaporator was full of crap when I pulled the box to replace the valve.

 

By the way...I assume the orifice is in the Expansion vale assembly..am i correct. I did follow the link to autozone but it just came up with a zip code request..when I did that the part that came up was a window motor...?

Scott

[John Boy]

The element inside the filter drier does corrode and clog up at the TEV. It happened to my truck.

[msavides]

By the way...I assume the orifice is in the Expansion vale assembly..am i correct. I did follow the link to autozone but it just came up with a zip code request..when I did that the part that came up was a window motor...?

Scott

 

 

 

Stupid autozone web site. Yea it was the expansion valve

 

http://www.autozone.com/R,1825361/vehicleI...oductDetail.htm

 

Mark