93 Previa AC and other questions

[capsulej]

Hi folks,

I just recently purchased a 93 Previa and have been trying to fix it up a bit. Was wondering if anyone knew where the A/C recharge ports are? I have heard it is under the passengers seat but i cant seem to find them. Pictures would help.

Also, does the 93 use R-12 or 134A?

Things I have fixed so far:

New Radiator
EGR valve cleaned (not sure how necessary this was)
Spark plugs
New battery/cleaned the corrosion out of the battery fuse box.
New tires

Bought a new cap/rotor but the one I have already looked pretty new so i didn't replace it. I also did the valve cover gasket, but there is still a small leak so im not sure if i have it too tight or too loose maybe? Or it could be the distributor leaking.. i might revisit the cap+rotor again.

I also drained the transmission fluid but i was unable to get the pan off and the brittle metal started to crack when i tried to pry it off. I don't think the trans fluid has ever been done on this thing. I let it drain for a couple days and i added new fluid but now i notice it makes more of a "clunk" noise when i shift sometimes. Not sure if this is a bad sign or not.

I have also heard it can be beneficial to change the differential fluid. Is this necessary?

Lastly, does anyone know what these wires are for near the spare tire holder on the back? The previous owner had no idea..

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[tbkilb01]

Under the bonnet- hood. Originally r-12. Should tell you under hood if has been fitted with 134. If not, you can tell by the fittings. 134 uses quick disconnect fittings. Your looking for a blue cap,if it has one. Different sizes. theres a site glass that will give you a clue as to how much freon is in there! If r12 goodluck...you may have to convert to 134, not hard at all...
Let transmission warm up, then check level on red dipstick under drivers seat engine access . If it's low add it a pint at a time till reaches full mark! not a whole quart. The tranny filter really gets gummed up. Usually comes with new gasket. Really should revisit that. It's just stuck on. Rear diff needs changing, yes. Be sure an get the right socket wrench on it and remove fill plug before draining! Fill till it runs out!
The wires are for trailer lights if pulling one.

[capsulej]

Well using your advice i managed to find what I think are the A/C recharge points. The bad news is that it looks like it is R-12.. I couldn't find a site glass anywhere. Is there a location I am supposed to be looking? A red arrow on pic 3 would help...

I took a look at the tranny fluid and it doesn't look low to me. The dipstick just has a hot/cold point, not a high/low. The sound is most noticeable when i switch between reverse/D or park/reverse.

I also cleaned the throttle body a bit. The metal flap that turns for air intake had a lot of black grime on it but i don't see how that would affect its function since it wasn't stuck or anything.

When i first got the car it noticed it kind of sounded like the engine would "jump" and sound like it was working a lot harder and go back down to normal again.. after i did all this stuff it got better but its still there. I wonder if there is a pressure issue somewhere, since it looked like maybe thats what blew the radiator as it was leaking from the top if i remember correctly. Could it have a thermostat issue? I dont even want to imagine how hard that is to get to on this car. I know these things have head gasket issues, but i don't get any stalling or white exhaust when i turn it on.

Also, not sure if this is related but sometimes i will hear a clicking noise when i stop at a traffic light with the window down. If i move forward and stop again it goes away.

My mechanic said he didn't notice any strange engine noises when he drove it so maybe i am just over sensitive to this stuff. It is an old car after all.

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[zak99b5]

The top notch (closest to the handle) is the hot full mark; the one directly below it is the low hot mark.

The cold range isn't very useful.

Drive around for twenty-thirty minutes or so around town (not freeway). Then park it on a level spot, leaving the engine running. Step on the brake and cycle the gear selector through all positions then back to park.

With it still running, open the hatch and pull the dipstick. Wipe clean, reinsert, and pull again to get the reading. Hold the dipstick level so the fluid doesn't run up and give a false reading.

As for the A/C sight glass, it's near the condensor, by the radiator. Mine is hard to see. Follow the lines leading to it, and you'll find it.

What about the coolant leaking at the rad?? It's under pressure when it's hot, so that is normal, and it can leak from any crack or loose joint in the system. Maybe you need a new rad? How is your engine temp? The thermostat isn't that hard; you just need to crawl under the van to access it.

Clicking sound when stopped at idle in D can be a few things. If you put it in P or N does it go away? On mine, the SADS bushings were shot, and they made noise when stopped and idling in Drive, and it went away as soon as I started driving.

[tbkilb01]

Radiator comes out very easy. Pull it and have radiator shop test it. The one I used didn't charge me at all. Better safe than...blown head gasket. As long as your troubleshooting. Also clean out reservoir really good and check return hose for clogging. Clean out cooling system period. All kinds of stuff in there after years of service. Then use Toyota antifreeze! Clicking noise is audible cuz your right above engine, could be normal injector noise, tiny exhaust leak...any number of sounds...

[capsulej]

Hmm, I did what you suggested and the dipstick was almost at the hot full line. Strange because i didn't get this noise until i drained+refilled the fluid.

Makes me wonder if there is a clog somewhere. I have heard a lot of bad stuff about flushing the trans though. I will try and buy a new pan+gasket, maybe thats whats causing it?

Update- Ok, managed to find the sightglass, turns out it was under a lot of grease. It looks like there is nothing in there, or maybe the liquid has solidified. And when i turn the a/c on i dont notice any movement or bubbles. Is this normal?

I did notice that there is another capped off point directly on top of the compressor, anyone know what this is for? The caps in the first picture are directly connected/beneath the blower assembly, so im pretty sure this is the high/low pressure point for the ac lines.

Yes, the radiator is easy to get out - i know because i have replaced it already. The leaks i was referring to were on the old radiator.

[tbkilb01]

Clear means either full or empty..if it doesn't cool, probably empty. Maybe a leak, could be easy could be expensive. Taking it to shop is going to cost ya, especially for a vacuum pulled on system to check for leaks and recovering R12 ( if any) and filling with r134. If your brave as I was, Walmart had all I needed. I got lucky. Mine hadn't been run in years. So I chanced it. I Used compatible oil in case low on oil, I used sealant to lubricate o-rings, and filled with r134a. Now I know there not compatible, It may damage o- rings, it may tear up compressor... But I got lucky, it's been 3 years and no leaks from front or back, comprssor still compresses, and it cools to 40ish at vent. But I only use it when it rains for defroster. It's not hot down here or I drive other vehicle. The Previa never really cooled that welleven less on r134. Again, it's an old system, really need converting since r12 is hard to buy and expensive. Allot can be/go wrong. Like I said I run mine to keep circulating the system, and hopefully keep it defrosting and not for comfort.

[capsulej]

Clear means either full or empty..if it doesn't cool, probably empty. Maybe a leak, could be easy could be expensive. Taking it to shop is going to cost ya, especially for a vacuum pulled on system to check for leaks and recovering R12 ( if any) and filling with r134. If your brave as I was, Walmart had all I needed. I got lucky. Mine hadn't been run in years. So I chanced it. I Used compatible oil in case low on oil, I used sealant to lubricate o-rings, and filled with r134a. Now I know there not compatible, It may damage o- rings, it may tear up compressor... But I got lucky, it's been 3 years and no leaks from front or back, comprssor still compresses, and it cools to 40ish at vent. But I only use it when it rains for defroster. It's not hot down here or I drive other vehicle. The Previa never really cooled that welleven less on r134. Again, it's an old system, really need converting since r12 is hard to buy and expensive. Allot can be/go wrong. Like I said I run mine to keep circulating the system, and hopefully keep it defrosting and not for comfort.

Did you pull a vacuum or just refill it yourself? The gauge+pump sets are pretty cheap on eBay so I was thinking of getting one just to test with. If it's possible to just refill it I may go that route.

[tbkilb01]

It's actually an ac recovery machine. Usually found at automotive repair shops. Me, I just got it going with gauge on can purchased at Walmart. I really was just checking to see if there was a leak and ended up not having any leak. After a can, the compressor kicked in. I filled per instructions on can. I purchased kit to update fittings and never opened up system. Should not cost that much to have system checked for leak. If you need ac, might invest to have it checked out by pro. To get it done right. Pressures, vacuum, leaks, compressor, evaporator, valves , etc. so many variables. I just use when I need to. It's not my daily driver anymore, more of a weekend camper....but it Worked for me. Some people doubt it but it's working still. Could breakdown tomorrow. I've had the van since new and never been to shop,so I really didn't feel comfortable letting someone else tinker on it. But ac systems are fairly easy unless you got component problems, then it gets too expensive to have fixed at shops. If you do it, research good! Know what your looking for. Fill it thru correct valve( low pressure side) and don't over fill. Be patient. Remember you have 2 units to turn on when filling! Do you have a shop manual?

just for Funsies
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still cooling( fingers crossed)!

[capsulej]

Hmm.. I tried pushing the Hi/Low ports with a screwdriver and there is still pressure. Also, some oil came out onto the screw driver. Is this a sign that the system is still functional? Im guessing the freon leaks a lot easier than the oil.

I may just give your refill idea a try and see what happens.

[tbkilb01]

It really needs to be done professionally. Your risking damage to your components. I'm just saying

[zak99b5]

Actually, R-12 isn't expensive anymore, as there isn't much demand.

You can also use Red Tek in place of R-12.

I have read that systems hold R-12 better than R-134a. Something to do with the molecules being smaller in R-134a so it can leak out of seals that hold R-12.

Get the gauge and pump cheaply, and see what kind of vac it can hold overnight.

If you do have a leak, first suspect is the expansion valve that's on the firewall, I believe inside the fresh air intake.

[Jbbishop2]

In case it's useful, Toyota Service Bulletin AC002-98 covers converting '86-'94 models from R-12 to R-134a at http://tms.cleanautoalliance.org/documents/ac002t98.pdf

[tbkilb01]

If you decide to go 134
bsure and get the retrofit fittings That screw onto old fittings!