ChrisWhewell

I don't have the service manual for my 90, wish I had one. So I use the one from my 98 riviera. On a 100 degree day of low humidity it states the AC discharge air temperature is 54-60 degrees. Since they're both 134a systems (assuming your reatta has been converted), that probably represents a best case scenario. For the same outdoor temperature but with high humidity, the book says 63-69 degrees. After passing through all the ductwork, if its delivering 72 F air on a 100 degree day, I'd suggest its working well. I think my Reatta delivers about 68 degree air when its 100 outside here in Texas. If you get the operating pressures correct, that's the best you can do I believe. . . Hey, question for the knowledgeable folk - is the orifice tube any different on a 90 Reatta originally designed for R12 as compared to a 98 Riv that had 134a from the factory ?? It might seem logical they would be different since they're for OEM different refrigerant gases. IF SO, then an AC trick for my 90 that's been converted, might be to install an orifice tube from the 98 Riviera's system....

Dude, you're amazing and amazingly helpful always on so many topics. Given your surgery successes, I hereby nominate you as Chief Reatta Surgeon. Thanks for all you put up on here.

Great thread here. Reattas are like "Camel Filters", remember the old TV commercials ? "They're not for everybody". Consider also the changing demographic in the States here - its not hard to predict that even the demand for '68 Camaro Rally Sports won't be increasing as we old americans die off. The "millenials" have no interest even in a GTO Judge model. If the Reatta didn't have such a cute curvy little butt and sleek side view, I would have gone for a porsche or whatever. Fact is, Reatta is probably one of the sexiest cars ever made. If I was a Jeep, I'd be doinking the Reatta every night. LOL.

All the negativeness aside, once you've done something to the car, it won't need to be done again. I had to fix my AC, put new struts in, upgraded the ignition system module and coils, inspected the ground connections under the rug behind the seats, changed out the ECM module, put the magnet back in the camshaft sprocket, changed all fluids, new transmission filter, fuel filter. So far my headlamp covers work fine. Also, my ABS sensor wire leads are ok but the deal is, there's lots of parts that are getting hard to find. So hard, that I bought a second Reatta so I could rob parts from it as needed. I also had to replace my trunk latch solenoid. Also, my electronics would randomly lock and unlock the doors and trunk. I finally figured out accidentally, the reason. It turns out that after I disconnected the trunk illumination bulb from the circuit, all the weird electonic happenings stopped !! I like my car because its challenging.

It'll be difficult to find a nearly 30 year old car that doesn't have any issues. Even if when you get it there are no issues, some issues will likely develop. I don't think these cars at this point in time are for owners who are unwilling to work on them, and also a lot of garage mechanic professionals are not motivated to learn about the idiosyncracies of these almost 30 year old vehicles. That's obviously just one man's opinio, take it for what its worth. If I had to pay someone to do all I've done on my 90 in the past year or so, the bill would have been around $5k on top of the purchase price. That said, the folks on here are knowledgeable for when issues pop up. Welcome to the forum, and good luck.

When you say old car enthusiasts, do you mean car enthusiasts who are old, or enthusiasts of old cars ? Or both ? ok, just joshing you, thats a nice car. Welcome

I've only seen it about 3 times. But I noticed the script on glovebox and running boards that says "Supercharged" appears to be of the same script as the Series II SC Riv's which came way later than 90. Also, my 90 has an airbag steering wheel and the SC 1990 model steer wheel appears from a different MY. I wasn't aware transmission issues are so huge on our cars until this thread.

The transmission is near the very end of that video but I can't make out which trans it is

Theres one dude out there with a SC Reatta, I think it was silver and supposed to be previously owned by a GM exec. I wonder what drivetrain is in that car....

Wow, some great postings here. Sorry to hear about your trans issue. If it were me, I'd write down the various options and put a time figure next to each, like how many hours each potential path might take, then balance it against cost and what else I have going on in life. On a trans, I generally just buy a rebuilt that comes with a guarantee. If selling the car, its a great selling point that the trans is new. So, in a way, a rebuilt with a warranty would help you achieve your aim of selling the vehicle !!

I drove a 93 vette for a decade and it was normal for operational coolant temp to be up to 237 deg. before the fans would kick on, that was the design spec

Installed rear struts; weatherized the abs leads.

The size of the molecules shouldn't matter at all, I think the issue stems mostly from R12 being used with mineral oil as a lubricant, wheras with 134a you're using a more polar lubricant, typically erythritol esters, and the issue is whether the o-ring material that is designed to withsttand non-polar mineral oil, will stand up to the more polar erythritol esters. Probably both are fine, when pure. But these systems, no matter how hard you try, will always contain or generate some water due to normal operation. Its the presence of water that causes/catalyzes o-ring decay. Another factor is the plasticizer used in the o-rings. There's always many factors most overlook, you have to be a good detective.

there is a lot of misinfo out there, look at this link below, they have the illustrations for R12 and R134a reversed. If people don't know the difference between a methane and an ethane molecule, they should shut up about chem. http://www.rtsauto.com/how-to-recharge-the-ac-in-your-car-eg-used-will-be-e30-and-how-to-use-ac-manifold-gauges-and-pull-vacuum R12 only has one carbon atom, 134a has two in a chain to which the F's are attached. Never trust an AC tech on chemistry, these guys come to my house trying to sell me new units everytime they come out and think they can pull one over on me, until I start talking like I know their shitt better than they do, then they get disappointed. I got my BS in that subject in 87 from Hope College, if it matters. As concerns my orifice tube, it is clear, just was replaced. If you look you will find compressors typically show high low side pressure right before they fail. So, mine's due any day now to pop. I think if you look into it further you can find the reason why high low side pressure is not always due to a clogged orifice tube.

Thanks Barney, and everyone

Thanks for that. Not only have "they" changed the gasoline so that it sucks, but they also took the zinc out of the motor oils. grrr. I run Harley Davidson motor oil in my John Deere lawn tractor

I didn't change my o-rings at all. Too much of a pain to hunt down, the people at local FLAPS generally have putty for brains and I remembered the last time I changed o-rings, took about a week to get everything right. Its been one year, no problems, AC blows cold. I'll add that I have a compressor problem, the low side pressure is waaayyy too high, and the system when running will only accept one 12 oz can of R134a before the pressure release pops. So, I'm running old o-rings and about half a charge but that's all she'll accept and it really blows cold. I'm perplexed. Also, R134a is not smaller than R12. 134a is tetrafluoro ethane, a two carbon backbone whereas R12 is dichloro-difluoromethane, only one carbon atom. both are halocarbons and the only diff I see that might matter is that R12 is a bit more polar and should only be an issue for seals when water is present in the system. If you keep it dry, use a new dessicant, etc., the old o-rings should be fine is what I suggest. Even though there are others with different opinions, that's what I see.

I guess its time I replace those loose horn buttons. I'm wondering what a good source or supplier would be. i.e., are all replacement horn buttons equal, or are some better than others ?? Thank you

I bought this car as a spare parts car but have changed my mind !! So I'm selling it, asking $750. The windshield is hopelessly cracked. The hood won't stay open without a proprod. One of the fenders makes the passenger door make a noise when you open it. Body is fair but no major accidents apparent. Here's the good: Engine is good, has 100k but the guy I got it from drove it 30 miles to get it here last year. The door skins and switches are all good. The headlight switch is good except the dimmer slider is loose. Both headlamps flip up and down ok. The Teves system works, apparently accumulator is ok. Transmission is also good no apparent issues. body side trim is good, trunk liner is good, Car is driveable. I have 4 hubcaps for it, one is not so good, the other three are pretty good. Rear tail light plastic cover is oxidized. The AC works just fine. Oh, and the tires are 90% and aren't that old. Location is Georgetown Texas and I have title in hand. If nobody wants it, send me a serious request for parts and I'll give you a decent deal if you need something, but I need to at least break even on this. What's a good running LN3 worth ?? Its not burning any oil. Oh, which catalytic convertor is on these ? Is it the one they give you $125 for ?? Probably has good brake leads also. I just need the space, otherwise I'd keep it. But, I'm also getting lazier in my old age, too much other stuff going on. I hate to get rid of it, but ... now's your chance, get me before I change my mind again !! The main display also works. use email to contact me agent ..at..inventorweb.com

Thanks ! I sent you an email. It'll be cool to have the original fob working

That's a tough question, lots of unknowns. It could even be that the bacterium cause water to separate out over time, if there's enough of them and their metabolism involves them pissing water, like we urinate. I think one needs to be careful, due to all the federal laws, what they recommend others to do, so I don't recommend anyone do anything. A few thoughts I'd put forth for researchers might be to use a little tetracycline or penicillin. Or perhaps an alkyl halide such as paradichlorbenzene. Possibly d-mannose might inhibit the bacteria's ability to stick to the sides of the tank. Or, alternately, glyceryl monolaurate (monolaurin). Yes, if I were a researcher, I'd definitely look into monolaurin as an additive. But, one issue is to not clog the fuel filter. In one extreme sense, chlorine bleach would work but probably corrode some components. A peroxide might be a good candidate, such as the urea peroxide in whitening dental pastes. I really don't know the answer, probably best to just go with what's been EPA approved and is on the market already, like the one you'd suggested. It would be nice to find the identity of the active ingredient and buy it in bulk to save money so we're not getting nickeled and dimed to death.

E10 can hold about 15 milliliters of water per gallon before phase separation occurs. But E10 is typically about 8.8% ethanol, so a gallon of typical E10 can hold about 12 ml of water. Once separation occurs, the E10 in the upper layer is saturated with water, which means any further absorption of more water due to condensation will precipitate out. This pretty much suggests to me that pump gas already contains substantial water. There are bacteria that live in gasoline, and they do better for themselves when water is present. Many bacteria, including thiobacilus ferrooxidans, thrive on sulfur also, which is present in gasolines to some extent. The bacterium cause oxidation / reduction reactions to occur, so I suggest that perhaps once a colony gets established in the vehicle's tank, the bacterium are what is causing the tank corrosion. If this theory is correct, which seems likely, the answer is to use a biocide in the fuel tank every so often.

I've had this gas smell also, haven't been able to figure it out. It would seem that the carbon canister is the only thing open to the air

I found a key fob transmitter in my trunk for my 1990, but,it doesn't have a back on it. It looks like it would be about the size of a quarter and made of plastic, you put the battery in and then that cover goes over it. I need the cover. . Also, looking for a good source for vats key blanks for 1998 Riviera if anyone has any suggestions or anybody on here sells them. Thank you.

MTBE is awesome. ARCO had extra t-butanol from its propylene oxide plant in Alabama in the early 70's so they reacted it with MeOH and made MTBE, and began selling it to refineries, who used it about 5 years before EPA found out. Then ARCO filed for a waiver and it was granted. Perfect additive. The ignorant crybaby legislators who banned it did so because of "leaking tanks", MTBE in the water supply. What a load of hogwash - if underground tanks are leaking, the remedy is to fix the tanks. It wasn't just MTBE leaking, it was gasoline, which also contains benzene, so those political whackos again make no sense. An executive of Ethyl Corp gave a speech to some of us students once, talking about how the bad guys were trying to get ethanol into gasoline for a long time. The problem with ethanol gasoline, is that the headspace in the tank can easily be in the range of explosibility limits, whereas when using MTBE, or even normal gasoline, it is not. Ethanol in fuel is a ripoff, nobody likes it except the people who are selling water as gasoline. I should teach the rednecks how to recover the alcohol. For $2 a gallon at 10%, you could get 12 ounces of 190 proof, which if cut with water to 95 proof would provide one fifth of "vodka", plus you can return the other 90% to the tank. Maybe if backwoodsers started making hooch from this crap gasoline they're now selling, it would force the industry to go back to normal fuel. Not. lol