Some help needed with my AC DIY repair

[mr_goat]

Hi, I'm hoping someone with good experience with the AC system for the NSX can chime in and give some advice. I'm in the middle of replacing my evaporator and have some questions.

My car has a harsh history. Been stolen and what not. The previous owner bought the car in 05 and drove it for one season (with broken AC, tried refill with R12 back then) and then just put it in a garage for a couple of years without driving it. I bought it i Feb in 2011, with a non-functioning AC and drove without it last summer, and it was HOT

Took it to a renowned AC shop that plugged it up and pressurized the system with dye. He found that it was indeed leaking, it was a small leak, he didn't immediatly see a leak, it was found the day after when the pressure had dropped by about 30 % from max. He had difficulties finding the leak but said the sniffer indicated gas at the center vent which pointed to the evap.

Now, I will start this repair by replacing the evap and the associated O-rings. Now, should I replace all O-rings for the AC-system before I take it back to the shop for a new pressure test? Just as a precaution because it has been sitting so long so there is a risk that they are dry? They are cheap and I have good access since my car is on jack stands already.

The manual says to "apply sealant to the AC line grommets" and to "apply a few drops of refrigerant oil to the O-rings" before refitting. What sealant? What oil?

Here are some pics of my progress so far:

Blower motor out:


The control unit rack on its way out:


Heater-evaporator on its way out:


//Johan

[nigel]

If your doing this repair do it all the way.
The rest of the o-rings are fairly easy to get to so replace them all.
Put a drop of a/c oil on the o-rings when you connect the fittings and Honda says to put a drop of Loc-Tite 242 / blue, to the threads as a sealant.
242 allows you to remove them at a later date but still seals.

Cheers
nigel

[goldNSX]

Now, I will start this repair by replacing the evap and the associated O-rings. Now, should I replace all O-rings for the AC-system before I take it back to the shop for a new pressure test? Just as a precaution because it has been sitting so long so there is a risk that they are dry? They are cheap and I have good access since my car is on jack stands already.

Be aware that there is a R12 and a R134a version of the o-rings. I did mount the later one as I went with 134a anyway. Replace all of them. R134a works at higher pressure. 850 gramm is what the system calls for. 950 with R12. As soon as the system is pressurised you can't change one of them. Replace the dryer too. I went with the 134a one which has a smaller holding bracket even though the manual says not to substitute R134a for R12 parts. Check the compressor too.

There's a good chance that something brakes in the near future if the system didn't run for 5 years. Maybe worth changing the compressor too as a preventative.

[ofdlt10]

i replaced my evaporator last year along with this:

switch- 80440-SLO-901 $ 77.72
receiver- 80351-SLO-305 $137.48
condenser- 80101-SLO-A02 $308.40


acura said they wouldn't recharge the system unless these items were replaced along with all the "O" rings. i also replaced both front coolant hoses.

after all this, nabil at first class automotive found a leak at the receiver around a new "O" ring.

replaced it and running cool ever since. since it's apart, don't take a chance. just replace them. it's cheap insurance.

[mr_goat]

Thanks guys! I'll replace the O-rings then. Can't find the Loctite 242 but I have found the 243, I checked them up on Loctite and theyre almost identical. I'll go with the 243, no objections?

If your doing this repair do it all the way.
The rest of the o-rings are fairly easy to get to so replace them all.
Put a drop of a/c oil on the o-rings when you connect the fittings and Honda says to put a drop of Loc-Tite 242 / blue, to the threads as a sealant.
242 allows you to remove them at at ater date but still seals.

Cheers
nigel

Thanks Nigel. Now, which A/C oil? I've found the PAG A/C oil for 134a which comes in three different viscosities, ISO 46 (thin), ISO 100 (medium) and ISO 150 (thick). Which one or should I get another brand?

Be aware that there is a R12 and a R134a version of the o-rings. I did mount the later one as I went with 134a anyway. Replace all of them. R134a works at higher pressure. 850 gramm is what the system calls for. 950 with R12. As soon as the system is pressurised you can't change one of them. Replace the dryer too. I went with the 134a one which has a smaller holding bracket even though the manual says not to substitute R134a for R12 parts. Check the compressor too.

There's a good chance that something brakes in the near future if the system didn't run for 5 years. Maybe worth changing the compressor too as a preventative.

Thanks! I'm going for the 134a conversion so I'll get those O-rings too. I'll probably get a new compressor too, while I am at it, good advice!



Have a look at the connections to the evaporator. Shouldn't there be any O-rings there?

[goldNSX]

Thanks guys! I'll replace the O-rings then. Can't find the Loctite 242 but I have found the 243, I checked them up on Loctite and theyre almost identical. I'll go with the 243, no objections?

I didn't use Loctite at all.

[mr_goat]

I didn't use Loctite at all.

Ok, it's just a precaution. I'll use it. What AC oil did you use?

[goldNSX]

Ok, it's just a precaution. I'll use it. What AC oil did you use?

R134a -> PAG, common oil the filling stations have. I had a problem to determine how much oil has to be filled. I had a big leak over several years and I lost freon and oil. But how much oil was lost, good question? As I changed the compressor to a new one I could guess it much better. 120 ml is the amount for the whole system. 850 gr R134a. I still had 20 ml in the old compressor even after sucking all the freon out of the system. See SM for the oil left in the system components.

[mr_goat]

R134a -> PAG, common oil the filling stations have. I had a problem to determine how much oil has to be filled. I had a big leak over several years and I lost freon and oil. But how much oil was lost, good question? As I changed the compressor to a new one I could guess it much better. 120 ml is the amount for the whole system. 850 gr R134a. I still had 20 ml in the old compressor even after sucking all the freon out of the system. See SM for the oil left in the system components.

Ok. I've found that PAG oil, but it comes in three different viscosities. ISO 46 (thin), ISO 100 (medium) and ISO 150 (thick). Do you have any preference?

I haven't evacuated the system and there were quite "a lot" of oil that came out from my old evap when I disconnected it. No pressure though since it has a leak somewhere. I'll let the AC shop take care of the evacuation, flushing and refilling, I'll do the repairs and replacements.

What about O-rings for the evaporator? It appears to be missing in the exploded chart above or shouldn't there be any?

[mr_goat]

There are two variants of O-ring #25:

025	80872-SL0-900	O-RING (1/2 in.)	006	1991	NSX	4.28	3.21	Qty:
025	91315-SE0-000	O-RING (1/2 in.)	006	1991	NSX	4.28	3.21	Qty:

Difference?

[goldNSX]

Just use the oil your filling station has.

The A/C parts of Acura are NOT supplied with o-rings. You have to buy them separately. I've a R134a evaporator in stock and it doesn't countain any o-rings. Same for dryer/receiver.

The oil is mixed with freon. If you loose freon you also loose oil. Good luck on guessing how much oil is still in the system.

[nigel]

Remember, if you are changing the compressor a HUGE savings is to use the Acura, I think Integra, (here in the states) compressor, someone verify me on that it is the Integra and not the Legend compressor, and swap the pulley so they spin the same speed and save yourself hundreds of $$$$$.
It is the same compressor just different pulleys.
You can get an a/c o-ring assortment pack at any auto parts store. 6 or so dollars, U.S..
Do install the "green" ones for R-134 as they are for higher pressure and the same price regardless of your freon grade.
ALL connections get an o-ring!


Cheers
nigel

[goldNSX]

...HUGE savings is to use the Acura...

The A/C compressor for an Acura NSX, Legend and Integra is the same price +-$10.

Do install the "green" ones for R-134 as they are for higher pressure and the same price regardless of your freon grade.

The main reason is that the material has changed as R134a has much smaller molecules than R12 and that R12 o-rings can get damaged if you use R134a unless you've put in the conversion oil Honda offered. This kit coats the o-rings so they can sustain R134a. But I regard this as a temporary fix. 20 years on o-rings is too much anyway.

[mr_goat]

The A/C compressor for an Acura NSX, Legend and Integra is the same price +-$10.


The main reason is that the material has changed as R134a has much smaller molecules than R12 and that R12 o-rings can get damaged if you use R134a unless you've put in the conversion oil Honda offered. This kit coats the o-rings so they can sustain R134a. But I regard this as a temporary fix. 20 years on o-rings is too much anyway.

What if I use the R143a O-rings and the AC-guy puts in "conversion" oil?
What are the part number for the R134a O-rings? These are the one I've found for the 1991:

002	80874-SL0-900	O-RING (3/8 in.)	001	1991	NSX	4.28	3.21	Qty:
003	80871-SL0-900	O-RING (5/8 in.)	003	1991	NSX	4.28	3.21	Qty:

024	91301-SM4-A00	O-RING (8MM)	003	1991	NSX	1.92	1.44	Qty:
025	80872-SL0-900	O-RING (1/2 in.)	006	1991	NSX	4.28	3.21	Qty:
025	91315-SE0-000	O-RING (1/2 in.)	006	1991	NSX	4.28	3.21	Qty:

Note that there are two different kinds of #25, but not for the other ones. Why? Difference?

Compressor for my 91 costs $432, which is not that bad.

[goldNSX]

Compressor for my 91 costs $432, which is not that bad.

Like I said, it would be worth to replace it.

You've to look for 94+ NSX parts. 91 is R12.

Why putting in conversion oil if you already replace the o-rings AND compressor? If you go with R134a I would install a R134a drier/receiver. It used an different/smaller holding plate. While replacing the evorporator why not using the R134a one? The only R134a missing are the hoses and the switch.

See here http://www.nsxprime.com/FAQ/Reference/tsb/92-027.htm and the rest of the service bulletin and a lot of questions will be obsolete.

[nigel]

Over here the price is much different between the NSX and Integra compressors.
Try getting hold of Tim Poliniak at HONDACURAPLANET and i'd bet it's a lot cheaper than from HUK even after freight, VAT, etc....

Cheers
nigel

[mr_goat]

Like I said, it would be worth to replace it.

You've to look for 94+ NSX parts. 91 is R12.

Why putting in conversion oil if you already replace the o-rings AND compressor? If you go with R134a I would install a R134a drier/receiver. It used an different/smaller holding plate. While replacing the evorporator why not using the R134a one? The only R134a missing are the hoses and the switch.

See here http://www.nsxprime.com/FAQ/Reference/tsb/92-027.htm and the rest of the service bulletin and a lot of questions will be obsolete.

Thanks for the link! Haven't seen that one before. Sorry to say though that I already have a new R12 dryer/reciever and a new R12 evaporator. I still have the R12 mineral oil in my system which needs to be evacuated. PAG oil and mineral oil does not mix. I think the easiest approach would be to substitute all parts for R12 ones and then convert with conversion oil after evacuating the system according to http://www.nsxprime.com/wiki/TSB_95-008


Checked the 95' NSX O-rings:

002	80874-SL0-900	O-RING (3/8 in.)	001	1995	NSX	4.28	3.21	Qty:
003	80871-SL0-900	O-RING (5/8 in.)	003	1995	NSX	4.28	3.21	Qty:

024	80873-SL0-900	O-RING (8MM)	003	1995	NSX	4.37	3.28	Qty:
025	80872-SL0-900	O-RING (1/2 in.)	006	1995	NSX	4.28	3.21	Qty:

They're exactly the same as for the 91'! Checked the 05':

022	80871-SL0-900	O-RING (5/8 in.)	003	2005	NSX	4.28	3.21	Qty:
023	80872-SL0-900	O-RING (1/2 in.)	006	2005	NSX	4.28	3.21	Qty:
024	80873-SL0-900	O-RING (8MM)	003	2005	NSX	4.37	3.28	Qty:
025	80874-SL0-900	O-RING (3/8 in.)	001	2005	NSX	4.28	3.21	Qty:

Also exactly the same, just renumbered in the exploded chart. WTF? Maybe the R12 ones for 91-92 NSX have been discontinued and the O-rings listed are the R134 replacements?

Over here the price is much different between the NSX and Integra compressors.
Try getting hold of Tim Poliniak at HONDACURAPLANET and i'd bet it's a lot cheaper than from HUK even after freight, VAT, etc....

Cheers
nigel

Hi, are you sure it's the same compressor? Just different pulleys? And a link to HONDACURAPLANET would be awesome, I want to check this out.

Thanks!

[mr_goat]

Got my evap out:



Looks like crap and smells like crap. After cleaning it I couldn't find any obvious holes though...

[goldNSX]

Thanks for the link! Haven't seen that one before. Sorry to say though that I already have a new R12 dryer/reciever and a new R12 evaporator. I still have the R12 mineral oil in my system which needs to be evacuated. PAG oil and mineral oil does not mix. I think the easiest approach would be to substitute all parts for R12 ones and then convert with conversion oil after evacuating the system according to

Yes, that's a way to do it but as you're changing part of the system anyway it's only the second best solution but it works for sure.

Getting all the mineral oil out of the system requires flushing all components. Most of the oil remains in the system even after evacuating. After a none-working period of 5 years it would be not a bad idea to flush it completely. Did you even find out what happened? Are you sure the compressor is not seized, no metal particels in the system? I would start with a complete refresh of the system before you change some of the parts which possibly fail in the near future due to an existing problem.

o-ring: R134a ones can sustain R12 but not vice versa. That may be the reason Honda cancelled the R12 ones. It's hard to find R12 anyway and it's expensive too.

Honda parts/prices: My last local order of parts on my continent was back in 2005. I saved $$$$ (yes, a very high 4-digit number) and maybe more than a year of waiting time with all my orders in the last 6 years. So, the continental prices are not relevant to me. That's not my fault. I'm just a economic subject who avoids price differentiation, waiting time and bad customer service (on my continent).

[mr_goat]

Getting all the mineral oil out of the system requires flushing all components. Most of the oil remains in the system even after evacuating. After a none-working period of 5 years it would be not a bad idea to flush it completely. Did you even find out what happened? Are you sure the compressor is not seized, no metal particels in the system? I would start with a complete refresh of the system before you change some of the parts which possibly fail in the near future due to an existing problem.

The last owner refilled with R12, that I know because I have the reciept for it. I do remember him saying it worked back then but the leak was there so it would only have worked for a couple of days. I'm thinking like this: I replace the evap, o-rings, compressor and dryer/reciever. Then let the AC shop evacuate, flush, pressure check and if ok, convert to R134a and fill/test system. This way I don't have to estimate the oil contents, since it is being flushed out anyway. 120 ml of Honda PAG conversion oil and 850 grams of R134a right in there and this summer should be nice and cool.

What do you think? Does it sound like a sound plan? Have I missed something?

Honda parts/prices: My last local order of parts on my continent was back in 2005. I saved $$$$ (yes, a very high 4-digit number) and maybe more than a year of waiting time with all my orders in the last 6 years. So, the continental prices are not relevant to me. :tonque: That's not my fault. I'm just a economic subject who avoids price differentiation, waiting time and bad customer service (on my continent).

So what's your continent?

[goldNSX]

So what's your continent?

Same as yours.

[mr_goat]

Old vs new, ugly vs shiny

[mr_goat]

Getting all the mineral oil out of the system requires flushing all components. Most of the oil remains in the system even after evacuating. After a none-working period of 5 years it would be not a bad idea to flush it completely. Did you even find out what happened? Are you sure the compressor is not seized, no metal particels in the system? I would start with a complete refresh of the system before you change some of the parts which possibly fail in the near future due to an existing problem.

About the flushing. I think the best approach at this moment would be to remove my AC lines and condensers and have them flushed. I'll take them to the AC shop. That way, I'll get rid of all the mineral oil (and contaminants) in the system since the evap, drier and compressor are new. Then reinstall, pressure test, fill and system check

[TomCat]

Old vs new, ugly vs shiny

My 1991 NSX has a rubber covering over the bulb at the end of the copper tube on the expansion valve that seems to be adhearing/sealing to the "in" tube going to the valve. The rubber cover in these pictures does not look like it is very secure/tight.

If I try to remove my old/original bulb it seems that it will damage the rubber cover. Does your cover look "specialized"...as though it serves some engineered purpose (sealed/insulating/etc...) or does it just look like a protective cover?

[mr_goat]

Some updates. I've got cold air!

Evaporator installed, new drier installed.

Removed my lines and condensers, flushed them with paint thinner (doesn't leave a residue). A lot of old gunk and oil came out. Reinstalled with new O-rings, broke one pipe doing so so I ordered a new one (93+ type with R134a type triple switch, yes it fits) and installed it (the correct way this time).

Poured the mineral oil out of the new compressor, poured 130 ml of new ESTER A/C oil in it thorugh the suction fitting, which is compatible with both R134a and R12 and both types of o-ring materials, got a new clutch assembly for the 93+ (yes it fits perfectly onto the 91-92 type compressors) and installed everything back onto the engine.

Took it to the A/C shop this morning and they evacuated it, pressure tested it (no leaks!) and filled with 800 grams of R134a and now it works!

It doesn't blow ice flakes but it is cold enough.

A rewarding experience to do and learn this by myself. Thanks to all, especially goldNSX for all the help!