2G About to put A/C back in operation -- any hints or thoughts?

[waltah]

My 95 GS-T came with no A/C belt or idler pulley/bracket. I've gotten the bracket assembly and what claims to be the right belt and in the next few days I'll put them in. This is the usual 'looks impossible because there's not enough space for even fingers, let alone tools' job but probably it can be done. Remove a few parts blocking the way -- A/C hose bracket, undo a connector, and support bracket for it, couple of vacuum hoses and in theory it should be possible. For the belt, release the alternator belt and take it off the crank pulley then put on the A/C belt, tension that, reinstall and tension the alternator belt and should be good to go.

Any suggestions, comments, whatever?

Of course whether the A/C system will work or not is a whole separate issue. It does appear to be all there, closed up, and connected, the compressor pulley turns freely, so ... hopefully ...

 

[luv2rallye]

Perhaps not reinstall the alt belt immediately in case you have problems and need to remove the just installed AC belt.

 

[Mech Addict]

Get ready for comfort…?
Hard to believe this was considered an “option “ on cars for so long. I don’t think you can find any new car without it. I have to admit out of all the systems on the car, a/c is the one I try not to touch.
I hope you’re shivering soon!

 

[waltah]

The A/C idler pulley and belt are installed: My hands are 'medium-large' as American hands go and 'medium' for Japanese hands would be a lot better but aside from that it wasn't unreasonably hard. However:

1. The A/C doesn't work. The light comes on in the dash button but nothing happens. So probably the system -- although apparently closed -- is too low on refrigerant to energize the clutch. (The clutch and rev counter connector on top of the compressor is hooked up.) I'll stick a gauge on it the next time weather allows and go from there. There are no signs of leakage in the easy-to-see places.

2. The idler pulley rubs on the lower timing belt cover. This is because the top of the TB cover is too far out from the block -- maybe 3 mm or so -- and there's not supposed to be much clearance between it and the idler. It's as if some non-moving part under there sticks out too far. There's lots of clearance between the cover and the TB itself but when I push the cover in (closing up the gaps at the top edges and creating clearance to the idler) it won't stay. So 'sum ting wong.'

Probably I'll check the system pressure and do the next step of A/C diagnosis: If it's going to need a new compressor this would be a good time to know that. Then take off the lower timing cover and figure out what's with that.

Also the various ground straps on the engine seem rather ... creative. For example before I could free up the alternator I had to move a heavy strap running from the alternator to the power steering pump bracket. Does anyone know if that's standard?

On 27 year-old cars 'the problem' is never just The Problem. There are always layers. You do not buy one of these and simply drive it as you might a five-year old Toyota.

 

[Mech Addict]

I had something similar with my lower cover (though 6-bolt). The belt carved a nice slot in the cover. In my case I deduced (rightly or not) that some of the cover bolts loosened a little, and rubbing against the belt heated and warped the cover, which bowed out even more against the belt. I put in a new lower cover and clearance was fine.
Maybe post a pick of that ground strap; doesn’t sound like oem.

 

[Mech Addict]

See…

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[waltah]

Lots of progress in a couple days of good weather -- despite an overnight rain.

Yesterday I put the gauge set on the system, there was a tiny bit of pressure showing indicating that it has been closed -- a very good thing. I put a vacuum pump on it, it pulled right down and held. So probably no leaks -- though sometimes you can have a leak that's pressure-only.

Today I put a 30" vacuum on it for half an hour (boil away any bad stuff & traces of air) then put in a few oz of R-134a. This got the low side pressure up around 50 psi: It should only take about 30 to get the compressor going but no joy. (This feature protects against running the compressor on an empty system which would destroy it because no oil circulating.) To get the rest of the can in I pulled and jumpered the clutch relay. This got the compressor cranking and the rest of the fill was no problem -- put in 24 oz.

Book says about 25-26 oz but I had a clear sight glass with 24 and there's no point in fine tuning until it's known to actually be working. The temperature today was about 60 -- a bit low to be checking out an A/C system and the gauge readings were a bit off -- low side about 25 psi rather than 20, high side a bit under 100 rather than a bit above. Could indicate a problem or maybe not -- when we get a warmer day I'll check it again.

The A/C does work, though the vent temperature was only around 50 rather than 40 or so as per the book. One of the problems in the 90's Mitsu's on which I've pulled the evaporator assembly is that the seals on the various dampers have crumbled away so you can't 100% shut off the hot air.

I didn't add oil because the system had dyed oil --- that's not factory, is it? --- so probably had extra oil added in the past. I didn't change the dryer cartridge because the system seemed not to have been open. Both these decisions might be wrong.

Why the need to jumper the clutch relay? I pulled the horn relay, shoved it in the A/C clutch hole and everything started to work -- so it was a bad relay. You don't see a lot of those.

That leaves the bulged lower timing cover but it was only barely dragging on the idler and by the time all the above got done there was no more sound from it. I'll take a close look at it tomorrow and if no sign of things getting worse I'll call the job finished until a new lower and intermediate TC show up.

Thanks for the picture of the 6-bolt timing covers, Mech -- that clarified some things.

A couple of pictures sometime soon.

 

[waltah]

A couple of days after the above I checked the A/C again. Very little cooling, high side pressure around 50 PSI rather than over 100, bubbles/foam in sight glass. So there's a leak somewhere. I went out at night and went over the system with a UV flashlight -- nothing unexpected. So ...

1. Any thoughts on where a leak is likely where it can't be seen? Inside the evaporator I guess but I sure don't smell anything inside the car. I haven't looked at the compressor from underneath but usually a compressor leak sprays so much oil around that it's easy to see.

I added R-134a back up to full charge (until sight glass was again clear) and again checked cooling. 'Some, but wimpy.' Temperature in center vent 48 degrees, should be 40. Pressures -- low side not less than 25 PSI (should be 20), high side 100-110 PSI. One more oddity: Suction pressure swinging 26-30 PSI while charging, 1 to 2 second period. I've never seen that before.

The high pressure on the low side is enough to account for the poor cooling.

2. What's going on? Besides the leak, could this be a system with far too much oil?

So another layer of problems. Obviously the leak has to be found first, then I guess most of the system has to be pulled out, flushed with solvent, blown out, and start again from the beginning. Except the compressor -- those just get oil drained/pumped out, no solvent.

I can see if I can find the evaporator condensate drain hose, take that off, and turn the UV light on the inside. If there's a leak in the evaporator case surely there's oil there.

Any suggestions?

 

[1990TSIAWDTALON]

When I service my a/c on my other vehicles (not my DSM's), I am always shooting for 25-35 on the low side and 200-250 on the high side (on a hot day those will be a little higher). Maybe you just don't have enough refrigerant in it or are DSM's that much different than domestic vehicles???

 

[waltah]

When I service my a/c on my other vehicles (not my DSM's), I am always shooting for 25-35 on the low side and 200-250 on the high side (on a hot day those will be a little higher). Maybe you just don't have enough refrigerant in it or are DSM's that much different than domestic vehicles???

I think that's part of the low-cooling issue. The manual says that the sight glass clears slightly before the full charge/maximum cooling point is reached. Also ambient temps have been at the low end of the range so I've been somewhat guessing the correct pressures and might have undershot just a bit.

Another factor is not changing the dryer cartridge yet: Too much moisture absorbed there can restrict flow which will reduce cooling. There's really no telling when that cartridge was replaced -- it is the OEM design with just one tapped hole for the pressure switch.

The big issue remains the leak: I can get it going close-to-okay but in a couple of days it's down to 50 PSI on the high side and bubbles in the sight glass again. Last night I put it up on ramps and spent half an hour going over it with the UV flashlight, top, underneath, both sides of the condensor (as much as you can see of it), the plumbing, especially connections, ducts in the passenger compartment. The only place there was any sign of possible leakage was the body of the compressor which looked like it had been splatter painted with yellow-green glowing oil. No pattern showing leakage from a connection, not drenched -- just lots and lots of small bright dots, all over.

Compressor leaks are shaft seal failures. Since the car has 150k miles I probably will order a new compressor and go from there.

Darned if I could find the evaporator drain hose. Should be on the firewall somewhere below the refrigerant connections but didn't see it. Anybody know where to look?

 

[1990TSIAWDTALON]

I've come to the point where I just replace the compressor usually and all lines and components except the evaporator. Chasing leaks like you described have usually pointed back to the compressor seals. Good luck, gotta love a DSM with A/C!

 

[waltah]

Well, I'm kind of puzzled ...

The parts car system had a full charge and the compressor pulley spins freely so I'm going to swap that into my driver. All has gone well (except for the usual air-wrench tightened bolts and larger than Japanese-size hands) down to the bottom compressor mounting bolt on the pulley end which seems to be down in the frame out of reach. Or ???

I can't even feel the thing and of course I can't see the place it should be. Feeling the contour of the compressor I get to a frame surface before the place the bolt should be. This is probably something stupid but ... how do you reach that thing? Jack up the engine? The shop manual gives no hint of an issue.

Car is non-running and something of a mess (from before I got it) but at least the upper engine mounts are in place.

Edit: AH-HA! Looking at it from underneath it's clear that a plastic cover over the top of the steering gear had been pushed up over the head of the bolt in question and was hung up there, completely hiding it from above. A pry bar corrected that and I now just have to remove that bolt from above in the normal way.

 

[AWD-Tony]

You should be able to get to all the bolts for the compressor if that’s what you’re asking but you may have to remove the drivers side axle.

 

[waltah]

Got the parts compressor out okay with just one issue: I could not find enough clearance with any way I turned the thing to pull it up and out. I'm somewhat hampered by not having the upper body strength I had in past decades -- I can pick it up okay with one hand but holding it up while turning it different ways to try the fit is not now possible. Instead I put it out of the way under the intake manifold and removed the compressor bracket: That gave ample room.

The same sort of swap between a pair of 4g64 cars last summer went off without major trouble but the Expo has just a bit more space in the engine compartment.

I'll pull the one from the car in the avatar later today using the same technique and then put everything back together tomorrow if there are no major snags.

 

[AWD-Tony]

I do remember it being a pain to remove the compressor. It’s been 20+ years for me. Think it came out the bottom but my memory on this is a little fuzzy.

 

[waltah]

Got the compressor swapped. This is actually straightforward once the trick is discovered. Clear obstructions from above, remove the belt from the compressor and idler, unhook the electrical and refrigerant connections, unbolt the compressor from the bracket and push it out of the way under the intake manifold. Then unbolt and remove the compressor bracket -- a challenge because the upper two bolts are recessed and you're working under the bracket overhang. With the bracket out there's plenty of room to remove the compressor.

It isn't necessary to remove the idler arm from the bracket when removing/replacing.

Installation is the reverse: Compressor goes in first, push it out of the way and bolt on the bracket, then pull the compressor back, insert all four bolts (the bottom two can't be inserted once it's in position), pick it up and set on the tabs on the bracket, start the top upper driver's side bolt ...

Charged it up and things were better -- still had useful cooling after a couple of days but the pressures were definitely down some. Phooey Then while trying to help another DSMer reinstall A/C I happened to look under the battery bracket at the connections to the evaporator. Hunh! Thought I had looked there before, but ... Grit trapped in oil and when I went out at night and turned the UV flashlight on it, a nasty yellow-green glow.

So, today I pulled the battery and tray, removed the two evaporator connections, and replaced the o-rings. The old ones were OEM: They looked okay but there was clearly a leak there. Charged it up again, adequate cooling, but high side pressure a bit high -- 130 PSI when 110 is expected. Glass was clear though.

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The leaking connection after cleanup and replacement of o-rings.

In further proof of 'layers' in a DSM problem after reconnecting with new o-rings I felt around the connection and there was definitely something blowing on my finger. However it was there with the A/C off as well, if the blower was on high. So a small air leak from the evaporator case and rather high blower pressure, meaning the evaporator air side is dirty.

No surprise there -- I've never bought a car that had a clean evaporator. I'll drive it long enough to see whether the refrigerant leaks are gone and then pull the evaporator and clean it.

Or better, pull and clean the parts car evaporator so all that's needed is a straight swap. Doing it that way reduces the number of 'oops!' and gives time to order parts if needed.

You wonder what were they thinking not providing a cabin air filter on those systems. Showed up in 3g, right?

 

[1990TSIAWDTALON]

Do yo mean the evaporator "outside" is dirty? Very possible to be restricting air flow when we don't have a screen or prefilters.
If you were speaking of the "inside" of the evaporator, I have cleaned the inside with parts store a/c line cleaner, then blew it all out with compressed air before I reassembled the a/c components and pulled a vacuum on it. It worked very well and what ever it was smelled like citrus or orange peel. Cleaned out the evaporator good tho.

 

[waltah]

Do yo mean the evaporator "outside" is dirty? Very possible to be restricting air flow when we don't have a screen or prefilters.
If you were speaking of the "inside" of the evaporator, I have cleaned the inside with parts store a/c line cleaner, then blew it all out with compressed air before I reassembled the a/c components and pulled a vacuum on it. It worked very well and what ever it was smelled like citrus or orange peel. Cleaned out the evaporator good tho.

Yep, the 'outside' or the 'air' side as opposed to the refrigerant side. I started pulling the unit from the parts car today. About the same job as on the Expos that I've done except that you have to take out the battery and tray in the engine compartment to get good access to the refrigerant lines.

I'll do the refrigerant side while I've got it apart. You're supposed to take off the expansion valve to do that as I recall.

I still can't find the drain hose. The manual shows it right below the refrigerant lines but I can't make any sense of what I see and feel down there. However the picture will probably clarify when the box is pulled on the inside.

This always looks like a huge job but it's really not that bad and it makes such a difference in how the A/C works that it's worth it.

 

[waltah]

Drain hose found & removed, all the things mentioned in the manual are either loose or my car doesn't have that, and the darn box still doesn't come out -- it'll move around freely for about 1/4" and then is blocked by something I can't see. Not much fun working in cold windy weather but next warmer day I'll get under there on my back and try to see what's wrong.

Maybe a bit of brute force ...

The parts car is sort of a mess but I'm starting to think it's too solid a body to be parted out and maybe I'll see if I can get it running this summer. It came without a key so today I made one. Door handles are gone, there was a door lock cylinder assembly lying in the trunk but for a different car so I fixed it for the same key as the rest. I think I can get the title ... Who knows?

 

[Mech Addict]

At least in cold weather you don’t need ac…
I think as dsm enthusiasts it is hard to be objective about how much work a parts car would need to be a driver. My best friend growing up, his dad had a beautiful 1960 Eldorado, and about 10 ‘59 and ‘60 “parts” cars. So when my buddy got his license, we cruised around in one of those junky 1959 “bat mobiles”. Depends on how much room you have to hold on to them, for one thing, and sometimes the tolerance of a spouse. Money and time, obviously, too. There’s only one of you, so how would that other car be different than what you already have better?

 

[waltah]

At least in cold weather you don’t need ac…
I think as dsm enthusiasts it is hard to be objective about how much work a parts car would need to be a driver. My best friend growing up, his dad had a beautiful 1960 Eldorado, and about 10 ‘59 and ‘60 “parts” cars. So when my buddy got his license, we cruised around in one of those junky 1959 “bat mobiles”. Depends on how much room you have to hold on to them, for one thing, and sometimes the tolerance of a spouse. Money and time, obviously, too. There’s only one of you, so how would that other car be different than what you already have better?

Absolutely right. Fortunately wunnerful wife & I see eye-to-eye on numbers of cars and parts cars. Basically this is a hobby that pays for itself by providing our transportation. The practical limits are time and keeping it a driveway hobby. We're 'country' but parts car space is limited to two, an Expo LRV and this one.

I've been making drivers out of near-dead Mitsubishis for a while. Typically there are several items to fix before it can go on the road and a few dozen more before it's 'okay'. Then a few more will show up over the next couple of years.

The parts car is getting more attention now partly because I like the work and partly because there isn't an inexhaustible supply of these cars. While this one looks scruffy and would need a lot of work, it seems solid and someone else might want to put it back in service. I've gotten a lot from it already but nearly all as exchanges. I can pass it on and find a truly clapped-out car to supply the odd size bolt or practice disassembling before doing it 'for real.'

The car was off the road a while, then driven several hundred miles, then 'lost power,' then the P.O.'s teenage son started to fix it (donno what 'it' was) and eventually lost interest with a lot of stuff disconnected but no major disassembly. Over the summer I'll figure it out to the point of either getting it running or knowing why I'm not going to do that and probably pass it on.

In breaking news the evaporator is out, yes it is filthy. I'll probably open it up to clean it tomorrow. Getting it out really was just a careful application of brute force -- for about an hour. Interestingly it had been out before but it must have been long ago, 'cause it's pretty well blocked up.

And I woke up in the night with a sudden inspiration about where the one missing door lock cylinder would be -- down inside the door with the smashed up handle still in place, of course. And there it was.

Someone in the past bought one of those pairs of door lock cylinders that come with their own 'doesn't match yours' key. I rebuilt the driver side cylinder to match the ignition key; now just need to do this one and the car will have a normal set of locks.

 

[waltah]

Evaporator is out.

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It's right behind the glove box and this is the side you see when you look under. Two connectors to the left are for the thermistors that control the compressor clutch, the one to the right is for the blower speed resistor that's inside.

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This is the side against the firewall. Refrigerant connections middle left, condensate drain lower right.

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This is the side facing the blower -- right side as mounted. Not very clean in there.

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With the top half of the case off (6 metal clips easily popped off with a flat screwdriver) it's clear that dirt and something fluffy like mouse fur have pretty well blocked the evaporator. Air flow at pressure might be down 90% but because the centrifugal blower speed (thus pressure) goes up when it's blocked the cooling might only be down 80% or so.

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Another view of dirt. Refrigerant comes in via the small pipe, is metered by the expansion valve according to the exhaust (suction) side temperature and pressure, boils away in the coils thus cooling the air, and leaves (to the compressor) via the large pipe from the upper left.

There's two bits of good news here: (1) no trace of oil anywhere, hence no leak. (2) The dirt has never been wet and can thus be vacuumed off quite easily.

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After vacuuming. Usually have to take the whole coil out of the case and at least soak in hot soapy water and hose through to remove stuck on dirt but this one was easy. Any sign of a leak -- oil traces anywhere -- would call for replacement.

Now it sits in the back seat of the car until (1) I'm convinced everything else is fixed, and (2) we get a good warm day so the two bundles of wire that the mounting tabs (two on top, one on bottom) have to go behind can more easily be moved around to get the thing in place.

Those harnesses make this the hardest evaporator to remove of any I've done. The rest is pretty easy.

 

[Mech Addict]

Great narrative and photo display. Thanks for taking the time away from your actual repair work. I usually get to immersed in the project to stop and do this.

I waned to do this when I had my whole dash pulled out, but I don’t have the equipment to remove the refrigerant. I imagine you’ll also clean out the heater core housing, or does the evaporator intercept the majority of debris?

 

[waltah]

You should be able to find a place that does A/C repair that'll recycle the refrigerant for you -- for a price. Especially once it becomes clear you're too cheap to replace lots of parts.

The truth is I don't know about the heater/defroster core but you've now shamed me into finding out. I'll take a look at the parts car unit sometime soon and report results.

I usually assume that weak heaters have trouble on the water side, usually because someone used a Stop-Leak on the radiator but ought to know the story on the air side as well and the only time is when the evap is out I think.

 

[Mech Addict]

My car was not drivable when the dash was out, or I would have gone to a shop as you suggested. And there is no shame implied on my part; I know at some level each part is somehow connected to every other part, and driving the car is the goal, not venturing down every rabbit hole imaginable.
But if you do pull it out, you’ll have at least one fellow enthusiast who will stare at the photos in detail.