Automotive Air Conditioning Information Forum (Archives)

cmeseadoin on Tue June 16, 2015 3:57 PM

Year: 1984
Make: Toyota
Model: Tercel
Engine Size: 1.5L
Refrigerant Type: R134-A
Ambient Temp: 92
Pressure Low: 20
Pressure High: 225-230
Country of Origin: United States

Hey guys,

I have just finished putting my Tercel's A/C back together as of about a month ago. I ordered a remanufactured Nippondense 10p13a from R&Y A/C Compressors in Miami Beach. I flushed the system, put in a new drier and flushed all lines. I realize that I don't know whether the condenser really is that well flushed based on my inability to see inside of it. I blew a lot of oil and brake clean through it and it seems to not be restricted based on compressed air and blake clean traveling through it.

I got the system recharged after vacuum and it is ice cold and cycling fine. I have driven the car for about a month with very well functioning a/c. When I added the new BVA auto 100 oil upon putting it together, I added a ounce or so of pag 46 with UV dye so that I could black light it if I had a leak. This past weekend, after several road trips and about a month to a month and a half of time running the system, I decided to black light the system. As soon as I got the blacklight on the compressor, I saw oil slinging from out between the compressor clutch plate and the drive pulley which means the front seal is leaking and blowing oil. I'm still ice cold air temps and I checked the pressures, I've never seen anything higher than say 225-30 on the high side...but I've gotten some conflicting info on how high the high side can get before it gets dangerous.

I talked to an A/C shop that believes I've just got a bad seal in the compressor and seems to think 300 and up would be the start of danger, yet I just got off the phone from R&Y who I bought the compressor from, and they are saying 240 is high enough to blow a seal. What do you guys think? I'm trying to decide if I just am having bad luck with the seal or whether I could have a head pressure causing a blowout. They are going to send me a new seal for free and I am going to R/R the compressor with the seal, then put it back together and recharge and look at pressures and leakage again.

What is a dangerous pressure for a Nippondenso 10p13a in a system like this '84 Toyota? Thoughts? :-)

HECAT on Tue June 16, 2015 8:44 PM

A seal for you to install? How nice of your supplier. The A/C shop is right.

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GM Tech on Tue June 16, 2015 10:08 PM

shaft seals are on the low side.......so high side pressure is irrelevant

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

cmeseadoin on Wed June 17, 2015 10:25 AM

cmeseadoin on Wed June 17, 2015 10:33 AM

Quote
Originally posted by: HECAT
A seal for you to install? How nice of your supplier. The A/C shop is right.

Yes, a seal for me to install. Since all of my diagnosis is pointing to a bad shaft seal....on a compressor that they supposedly "remanufactured" and seems to have failed. I have very little faith in anything remanufactured, most of it is pure garbage in the USA nowadays. If I had more faith in reman'd parts, I would request another compressor, however, I know this one does work "for now" but it is blowing oil from the front shaft seal.....I figure stick a seal in it and see what happens.

In addition, I have spoken to enough local folks that have extensive knowledge of A/C about the statements of R&Y compressors indicating that 240 was an excesive and high pressure for the system. That is not supported by my own observations in working with multiple A/C systems and is not a supported arguement from anyone I have spoken to. On a day where the ambient is in excess of 90-95 degrees and with relative humidity in the upper 80's to 90 some percent....225-230 is no where near an excessive high side pressure.

TRB on Wed June 17, 2015 10:34 AM

What options have you done to improve the condenser on this vehicle? The OEM 13 x 13 condenser will never remove enough heat for R134a to work correctly.

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cmeseadoin on Wed June 17, 2015 3:04 PM

Quote
Originally posted by: TRB
What options have you done to improve the condenser on this vehicle? The OEM 13 x 13 condenser will never remove enough heat for R134a to work correctly.

Well, at 90 degrees ambient, 80-85% relative humidity, high side pressure 200-225ish and low side in the 20ish range, vent temps are running 30-32 degrees once it runs for a bit and pulls it down. The compressor cycles as it should. It can get the air temps down into the 20's on a day when it is in the 80's. Based on that, I have concluded that the efficiency of this system running R134A is of zero concern to me. My concern is the leaking shaft seal and the ONLY possible two causes: Seal failure or a causation that could be proven to raise internal systems pressures to a dangerous "potential seal blowing" level. Unless the condenser can be proven to me to be blocked causing the potential to blow my shaft seal, I am not worried about it.

This condenser is 30 years old, I would be a fool to think it would be spotless on the inside....however, I have flushed the condenser as well as I can and it "seems" to be ok....I do not believe the high pressure side is causing the seal to leak....therefore, unless I get some earthshattering evidence on the contrary, I think the simplest thing to do is replace the shaft seal, re-seal the rest of the compressor housings when I do that, re-install, vacuum and leak check then rechange and monitor performance and pressures and the shaft seal.

The one simple question I was looking for some guidance on was whether or not an operating maximum high side pressure of 225-230 at 90-95ambient was a dangerous high side pressure that had the potential to blow a shaft seal.....in this application: A nippondenso 10p13a compressor. I've never thought it was, but then I talked to the remanufacture company of the compressor I bought, and the guy I spoke with said anything over 240 was too high. I don't buy it, have talked to others that don't buy it, and neither me nor the others I've spoken to are riding our first rodeo. So, I wanted to see if that was the general consensus of other A/C folks in the know. As with anything online, I read everyone's opinion, factor it all into my experience and knowledge and then use my intellect to decision the statistical probability that the information is or isn't likely the case.

bohica2xo on Fri June 19, 2015 12:55 AM

Interesting.

What pressure is your HPCO switch set at?

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
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cmeseadoin on Fri June 19, 2015 11:20 AM

Quote
Originally posted by: bohica2xo
Interesting.



What pressure is your HPCO switch set at?

That is an excellent question.....and it takes me to another observation I don't understand about this system. I have searched every line and the condenser and the dryer as well as the compressor under the hood. There is not one SINGLE switch ANYwhere to be found. My only thought is that there HAS to be something in the evap box. I know the expansion valve is in the evap box under the dash on this car. When I evacuate the unit, and flip the a/c on, the compressor will not engage obviously because something sees that there is no refrigerant pressure in the system. As I charge it and have the a/c on, once I get a few ounces in, the compressor kicks on. SO, there is SOME switch seeking pressure somewhere, but where it is would be beyond me at this point.

As of yesterday, I removed the compressor, tore it down, resealed the entire unit since to install the new shaft seal I removed the five main housing bolts, then installed a new shaft seal. Everything went like clockwork, got her all back together and have vacuumed and recharged it. This unit originally called for 1.76lbs of R-12, 28.16 oz) so I charged it to 24oz of R134-a or about 90%. Things are looking good as far as cooling and the shaft seal is not leaking thus far...however, high side pressure I am still wondering about though. I saw 250 on the high side at Mid 90's ambient. However, the backplate on the original Nippondenso compressor that was original to the car said that for R12, max pressure was 427. This 10p13a compressor was originally engineered for R12...so my 250 is a lot less than 400 something. I still am trying to get it out of my head that my High side pressure could be blowing the shaft seal. Someone did say on here that the shaft seal is on the low side...if that is true, then maybe I am just worried about something irrelevant. LOL

AC_Doc on Fri June 19, 2015 1:03 PM

Quote
I still am trying to get it out of my head that my High side pressure could be blowing the shaft seal. Someone did say on here that the shaft seal is on the low side...if that is true, then maybe I am just worried about something irrelevant. LOL

Yup!

I have a 1980 Tercel (still R-12 by the way). Freezes me out. There should be a small black box behind the glove box (little smaller than a cigarette pack) with a fluted shaft out the top mounted next to the evaporator box. This box contains an amplifier hooked up to an evaporator temp sensor buried in the evaporator core. There are no pressure sensor on my system. The 1984 system seems to follow suit.

Turning the fluted shaft will set the low temp that the compressor kicks out at. Not a whole lot of range on that adjustment either.

AC_Doc

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Sometimes you must accept things at faith value!

cmeseadoin on Mon June 22, 2015 11:33 AM

Quote
Originally posted by: AC_Doc
Quote
I still am trying to get it out of my head that my High side pressure could be blowing the shaft seal. Someone did say on here that the shaft seal is on the low side...if that is true, then maybe I am just worried about something irrelevant. LOL



Yup!



I have a 1980 Tercel (still R-12 by the way). Freezes me out. There should be a small black box behind the glove box (little smaller than a cigarette pack) with a fluted shaft out the top mounted next to the evaporator box. This box contains an amplifier hooked up to an evaporator temp sensor buried in the evaporator core. There are no pressure sensor on my system. The 1984 system seems to follow suit.



Turning the fluted shaft will set the low temp that the compressor kicks out at. Not a whole lot of range on that adjustment either.



AC_Doc

So, I had been behind the glove box a time before and seen the little black box you are talking about.....It has the knob for RPM on it, which I later figured out what the low RPM compressor coil cut out. I never messed with it beyond that. I went back in after reading your posting and took the box out, and on the back side facing the evap box, there was a silver foil sticker that had never been touched in 30 years, with Nippondenso stamped on it and a H ----> C turn know inside. I had to carefully cut the sticker away so I could see the set screw down in there. I messed with it while the A/C was on and sure enough, if you go towards C more, your compressor stays engaged longer for colder vent temps. I love cold air, so I dialed mine back a bit more to cold. It is working great....of course, the negative is that your compressor run times are longer between cycles and that means that little engine has a lot of power deducted, but I'll take it for the cold air, LOL. Also, my new compressor shaft seal is working great, so far so good! Cheers for the info.!!

mk378 on Mon June 22, 2015 2:19 PM

The main reason not to set it too cold is that the evaporator will ice up on the outside and block the airflow, causing the system to stop making cold air until you turn the compressor off for a while and let it thaw. The condensed water has to stay liquid so it can run out under the car.

cmeseadoin on Mon June 22, 2015 10:37 PM

Quote
Originally posted by: mk378
The main reason not to set it too cold is that the evaporator will ice up on the outside and block the airflow, causing the system to stop making cold air until you turn the compressor off for a while and let it thaw. The condensed water has to stay liquid so it can run out under the car.

That's correct, and that is why I did not tune it to the maximum cold setting..just a little more. I live in a very humid location and I have not seen any symptoms indicating evaporator freeze up but if I do I'll know exactly what it is.