DIY A/C repaired, transmission and exhaust mounts replaced, synthetic oil change DONE!

[qsiguy]

Spent about 10 hours on the Q last Saturday and got my a/c compressor and drier changed out, flushed and vacuumed out the system and got it recharged. Replaced the transmission and exhaust mounts which cured my annoying 2K +/- RPM vibration. Changed my oil and installed Mobile 1 synthetic truck/SUV formula.

LIFE IS GOOD! I finally have A/C again. It's no fun at 110 degrees with no A/C!

A/C repair went pretty smoothly as I did a lot of research before I began and made sure I had all the right tools. Swapping out the compressor and dryer were really quite easy. I had them out in 1.5 hours. The flush was a pain for a while. I was trying pour in the flush fluid through a 5/16th hose I had with a funnel which wasn't too hard. Then I went to blow it through the evaporator by just holding the hose over the a/c fitting. Not good, almost no way to hold it tight enough so the air and some flush fluid leaked out. Finally, I decided to get some fittings together with some hose clamps and that worked MUCH better. Then I could just clamp it on and flush all day long. Flushed the condenser next and it was simple with my new device (which I'll post a photo of below. I put a white cloth around the other end of the line so I could check for debris when I was done. Didn't get any pieces of anything from any components so I guess my old compressor just had a clutch failure.

Reinstalled the new (used) compressor and the new drier with new o-rings I got in a pack from Autozone which had the right sizes. I only needed 4 total and the pack came with a bunch of different sizes. The reinstall wasn't too hard either. The compressor is held in by 4 bolts. The only one that was a pain was the back one. It's pretty tight but it's not too bad. It helped getting it out that I had an air ratchet since with the hand one you couldn't move more than 1 click of the ratchet it was so tight. The idler pully is right next to the compressor so it was simple to get the belt off/on.

I had a venturi type vacuum pump but my air compressor doesn't have enough CFM to get the system down to 29" Hg and hold it. I had another small compressor so I put the fittings on the inlet for my manifold gauge and vacuumed it out with that. I know the goal is 29" but the best I could get with what I had was 26" so I let it run at that for 45 min. then removed it and let it sit for another 30 min while I went to pick up some R134a and oil. I ended up getting PAG 100 oil in a regular oil can, I spoke the the techs at Nissan because I couldn't find the PAG0S that the FSM called for and they said they use PAG 100-150. I wish I would have gotten the can with the threaded fitting to connect directly to the manifold gauge. I ended up having to close the valves, remove the low pressure line from my manifold guages, pour the oil into it until it was full, reinstall the line and blow it in to the a/c with R134a. I'm sure there is an easier way to get the oil in there but the can with the fitting is definitely the way to go. Would have saved me at least 1 hour.

After I got the oil in the rest of the recharge was simple and I had cold air again. I ended up putting in about 2.6 of the 12 oz cans (more on this later). I installed the transmission mount and did the oil change after that and got done around 10:30 pm, threw away my shirt, and it was done.

Drove it to work Monday morning and a/c was working great. Got to the office and a co-worker wanted to check out how cold it was blowing and what do you know, the a/c had died! NOOOOOO! All day I was so bummed! Didn't have my guages with me so couldn't even see what was up. After sweating all the way home at 109 degrees I got my guages on there and low and behold the pressures were to high on the low and high side. I vented a little freon (don't say it you tree huggers!) and shazam! cold air again. Boy was I relieved! Check the temp at the center vent and I'm getting 49 degrees at idle at 100 degrees ambient and down to 45 degrees while driving. Works for me!

So about the level and pressures. When I first charged it the engine was running for a while but in my garage and I took the pressures up to about 45 on the low side and 300-315 on the high side but I never drove it as it was on jack stands and I had more stuff to do. When the engine got hot driving the pressures shot up and the compressor wouldn't stay on any more. So The system will hold about 2 and 1/4 of the 12 oz cans. Some of the R134a that was at the store had 11 oz of freon and 2 oz of oil but I didn't want to use this so I could better regulate how much oil I has adding, plus if I only used that it would only be about 4-5 oz and Tech said in another thread that the system will hold about 8 oz.

The Q's running awesome now with the new transmission mount and the synthetic oil and I'm nice and cool inside.

LIFE IS GOOD!

Sorry this was so long, wanted to share. If any DIY'ers want to know how I did anything let me know. The job wasn't too bad.

Here is my flush tool

Compressor



My transmission mount was pretty flat!

Oh, and it looks like I'm gonna need some new tension rod bushings! Any good sources other than Joe for these? Maybe aftermarket ones?

[Rex]

I have a few sets (new OEM, used OEM, new ebay) of Tensions rods if you want to buy some fairly cheap.

[elwesso]

If your DIYing, getting the full rod would be best... you cna then get new bushingsin your rods and swap them out to have an extra set..

Anyway good job... Glad you got everything taken care of....

What flush fluid did you get..???

Also, did you realize the system is only supposed to take 1.7ish lbs.....? Its on the blue sticker.

[qsiguy]

The FSM contains everything one needs to know concerning oil amounts per component [the sum of which is 8 ounces]............7-8

R134a is a variable depending on the depth of evacuation 1.95-2.05 pounds should be close enough.....once the system has run in a few hours you decide upon amount extra or not by reading pressures.

Well, I had remembered Tech saying about 2 lbs. What I should have done but didn't remember is the part about adding some freon and then run the system a few hours before adding more. That's where I ran in to problems. I took it up to the recommended pressures before running it for a few hours. Then I was overfilled. You learn something new everyday I guess. I won't forget that one again!

Can I get some details on the tension rods you have available Rex? Price?

Thanks.

[elwesso]

Youll notice the procedure in the FSM how to properly read the pressures...

Hood openAC at maxRecircDrivers window open1500 RPMAmbient temp sensor shortedRun for 10 mins under these conditions before reading gauges...

[Jeff Williams]

Great job on the A/C repairs. I hope this helps others "take the plunge" into A/C work. It really is not that scary.

Don't feel bad about the overcahrge, I bet 20% of the guys out there getting paid to charge systems do the same thing. Of the 4 systems I have had checked and charged, 3 of them were over charged, and i had to "vent" a little bit.

For all you environmentalists, I kicked the neighbors dog right after I vented the refrigerant.

The transmission mount is definitely toast. I bet the engine mounts look the same. That was a good call on replacing it.

As far as the tension rods go. I have seen some bad ones in the past, but your's take the cake. I bet you wear out front tires a lot, and the guys at the alignment shop just shake their head when they check it. The 300zx tension rods are the same. The bushings are cheap from Joe. I have a set of 300zx rods that I got from a friend, who went fully adjustable on his tt. They had about 50K on them. I also bought a set of bushings from Joe, to install in my original rods, but haven't taken the time to press them in.

I would also buy all the sway bar bushings from Joe (it is about $30 worth of rubber). That should tighten up the suspension a bit.

Get some new power steering rack bushings while you are at it. They are probably worn, too. This could be causing some slop in the steering.

[texasoil]

The reason real A/C specialists use 2-stage vacuum pumps is the pull the system down to 50 microns or lower -29.995" of vacuum. At those pressures, ALL the water will come out. Water is enemy #1. Changing the filter/dryer is essential to long life since it not only traps up to a tablespoon of water, but also removes 'acids' that are formed when the refrigerant decomposes. Water +acids = hole in evaporator.

[qsiguy]

Now that I'm a self proclaimed "A/C expert" I think I'll keep an eye out for a nice vacuum pump. That would be a great tool to have. I already have friends wanting me to check out their A/C systems. When I find one I'll probably redo the Q since I wouldn't need to flush it again. That was the most time consuming and messy part.

Been monitoring the center a/c vent temps while I've been driving and it's working awesome. I've had temps as low as 37 degrees at 107 degrees ambient! Man I sure got this A/C fixed just in time. It was 114 yesterday and it's supposed to be hotter today!

Got my wifes van a/c working better last night too. I'll get some good points for that one when she drives it today! It was almost 2 cans of freon low. It holds a lot of freon as it has the rear a/c.

[Q45tech]

IF the ac works somewhat, you run the ac for 15 minutes just prior to the vacuum to get the water vapor as hot as possible..........so that if removes faster and easier...........unplug condenser fan relay/fuse......with a marginal vacuum pump every trick helps.

Cut open the old dryer to see the amount and type of contamination.

[qsiguy]

IF the ac works somewhat, you run the ac for 15 minutes just prior to the vacuum to get the water vapor as hot as possible..........so that if removes faster and easier...........unplug condenser fan relay/fuse......with a marginal vacuum pump every trick helps.

Cut open the old dryer to see the amount and type of contamination.

Thanks for the tip. My old compressor didn't work at all as the clutch and pully were grinding. Didn't catch it until I had the new compressor on and was beginning to fill it but the A/C fuse had blown from the load on the old compressor. I didn't get any pieces of anything with my flush but I'll have to cut open that dryer and check it out. Was going to anyway to see what it looked like.

What are your thoughts, Tech, on only getting the vacuum down to 26-27" on my system? I've read several different opinions on the subject. Do you think it would be wise to evacuate the system again when I find a proper vacuum pump and take it down to 29-30" and recharge it?

[paranoidjack]

hey, that floor in your pic....is that the rustoleum coating? I was going to do that in my basement this weekend, did you put it down?

[qsiguy]

hey, that floor in your pic....is that the rustoleum coating? I was going to do that in my basement this weekend, did you put it down?

I can't really remember the brand. I got it at Home Depot and it came in a box. It came with some citric acid to mix with water and wash the concrete, the epoxy mix, and the paint chips. Yes, I did it myself. First half I did by myself rolling on about a 4x4 section and they tossing down the paint chips. The second half went smoother as I just kept painting and my wife would follow behind and toss out the paint chips. The coat was more even doing it with a couple people. Turned out really nice and oil whipes up easily. I love it. I did the install bay at my old office with another brand and it was about the same. Just without the paint chips. I like the added texture and color with the paint chips. Hardest part was the prep work sweeping, washing sweeping, washing, drying, cleaning with acid mix, more washing, let dry and finally put down the epoxy. Well worth it tho.

Here's what it looked like after the first third of the garage was done.
Modified by qsiguy at 9:28 PM 7/14/2006

[FarFetched]

Good thing most vehicles don't have inline liquid filters/driers most common place to get clogged up. Also TХV valves are fun to diag. Good job man on A/C GET that 609 certification NOW.

[Q451990]

Shane,

I actually remembered your post and noticed the epoxy coating on the floor in your first picture. So I came back here just to ask if you liked the coating and if you would do it again - but apparently Paranoid Jack beat me to the punch! Have you had any issues with the coating? The former owner of my house apparently painted a yellow car in my garage - and didn't cover the floor first. I tried sanding a small part of it with a belt sander today it it takes the paint right off. I may rent a floor sander to get everything prepped properly - but at that point I'll have a nice clean floor so I may not make it to the epoxy paint!

If you had to do it over again, would you?

Heath

[qsiguy]

I will never have a garage without it. Looks cool and oil clean up is a breeze. No negative issues. Even if you clean up your concrete if you leave it "virgin" and spill oil or anything on it, it will stain and eventually you'll have ugly concrete again. The prep was the most difficult and time consuming part. If you have to do that anyway laying down the epoxy is the easy part.

Two of my neighbors paid to have theirs done (hundres of $$). Theirs is nicer as it has a thick clear coat over the top so it always looks wet. I love mine tho and for the price I'll keep doing it myself unless I win the lottery or something.

I will be doing my back patio when I get around to completing my back yard, will prob. use the tan coat for the patio instead of the grey.

[lavta3]

how do you add the freon to the car? where are the valves located?

[paranoidjack]

I will never have a garage without it. Looks cool and oil clean up is a breeze. No negative issues. Even if you clean up your concrete if you leave it "virgin" and spill oil or anything on it, it will stain and eventually you'll have ugly concrete again. The prep was the most difficult and time consuming part. If you have to do that anyway laying down the epoxy is the easy part.

Two of my neighbors paid to have theirs done (hundres of $$). Theirs is nicer as it has a thick clear coat over the top so it always looks wet. I love mine tho and for the price I'll keep doing it myself unless I win the lottery or something.

I will be doing my back patio when I get around to completing my back yard, will prob. use the tan coat for the patio instead of the grey.

thanks for the info man. I'll be doing my basement in the coming weeks. LOTS of prep to do!!!

[qsiguy]

how do you add the freon to the car? where are the valves located?

The low pressure inlet is on the passenger side of the engine bay towards the firewall. The high pressure inlet is on the passenger side of the radiator near the battery. It's best to have a manifold gauge set and you fill it through that into the low pressure side. I don't know your level of experience but if you need to ask where the fittings are you may not want to dive into A/C repair or maintenance. It can be very dangerous working with the A/C components and freon. The high pressure side can be higher than 300 PSI.