Actually I have a question: I know I'm gonna sound dumb, but I realized that the coolant I put in is not the right g12 coolant. And the coolant that was inside when I refilled it was also not the right one (it was blue-green instead of pink-purple). Is having the wrong coolant running a really bad thing? And is it possible that it caused a leak?
Also is it possible that running on low coolant for a week was somehow involved in the A/C that stopped working?

Thanks!!

 

If the previous coolant was mixed with G12, then it would have started to congeal, which is bad.

I would think if it congealed and raised the pressure in the system then maybe it could cause a leak, but I am not really sure.

I don't think the systems are tied together.

 

Ok so I brought the car to the mechanic and for the A/C not working he said the problem is just that when it's cold there's a sensor that prevents the A/C from running. And also the recirculation since its linked to the A/C. Is it true?
This would be the most ridiculous design flaw ever, so what during the winter I just have to choke on the exhausts of my car and others when I'm stuck in traffic?

Another thing that came up is that apparently when the previous owner installed an aftermarket exhaust system he got rid of the catalytic converter, which according to the mechanic is responsible for the awful smell of the exhausts and the code in the rear O2 sensor. He told me replacing the catalitic converter is very expensive (the part itself being around 1000 bucks). Is there any good cheaper aftermarket converter that I could install?

He also told me that the turbo valve code could be caused by the manual boost gauge the previous owner installed, does this make sense?


Thanks!

 

Ok so I did some research, seems like the A/C really is not supposed to work when it's below 40F. I still believe its ridiculous but whatever.

I also found out that not having the catalitic converter besides resulting in nasty toxic fumes, also makes the cur run rich, which would explain why I got such a bad mileage. How many hours of work are needed to install a catalitic converter?

Thanks!

 

Test pipes (the name of a straight pipe put in place of the catalytic converter) should not cause the engine to run rich. The primary O2 sensor, which controls fueling, is right after the turbo but before the catalytic converter (if you had one). So it reads the exhaust the same whether or not a catalytic converter if present.

Bad gas mileage can be caused by an old primary oxygen sensor, though.

 

My 97 A4 1.8T does the same wrt the AC snowflake shutting off when it is cold/freezing outside. Not sure at what temp this happens. The mechanic from your Jan 11 post is correct!

Fume smell: Try using the recirc button when stuck in heavy traffic to reduce smog intake into the cabin. Also, the smell may be coming from your car! It is possible that the crankcase vent pipe is cracked (058-103-221-A) or the tube (058-103-213) is leaking. I have changed that tube twice in the past 10 years. The first time it was done, I smelled similar fumes in the cabin.

Coolant leak: This is a common problem on B5s as they age. You need to find out where the leak is. One favourite place to look is at the coolant flange located the back of the 1.8T engine. Also, never mix G12 coolant and something else. It will gel like was posted earlier and will clog up your heater core and more.

Catalytic converter: Dealership quoted 3 hrs labour to remove/install a cat in my car (Oct 02).

Mark

 

Thanks!

About the cat, I did a research online and found several posts on forum (one was on this forum I'm pretty sure) where people said that the missing cat messes up the reading from the post-cat O2 sensor and as a consequence the ECU responds making the engine run rich just in case. Personally I have no idea, but it would make sense since I got 14 miles per gallon with basically a stock car, and that sounds quite low.
It could also be that the O2 is bad, is there any way to check if a sensor is bad besides the VAG?

Turned out that the mechanic doesn't think putting the cat back is important and seems like he doesn't wanna do it. Also he keeps complaning about the mods the previous owner did and that cars should not be modded... Think I need to find another mechanic.

 

The post-cat O2 sensor isn't used by the ECU for fueling adjustments; it's just a "snitch" that tells the ECU whether the cat is up to par or not.

You can replace an O2 sensor and see what changes are made, to see if the old one was bad. Even with VAG-COM you can't really test them until they are so bad that you get a CEL.

14mpg is pretty bad. I wouldn't blame the test pipe though unless it is causing an exhaust leak.

 

what would be even more ridiculous is if the manufacturer allowed the compressor to kick on when the refrigerant is liquid, allowing damage to the entire a/c system. i bet you'd get even more pissed then as it would be $$$$$ in repairs.

 

If the post cat O2 doesn't adjust the fuel I have to assume there's some other problem. Could it be related to the fact that they installed a manual boost controller?

About the A/C I understand there's a reason for this thing but I had other cars where I could turn the A/C on in the winter and not have to choose between asphyxiating or driving with fogged windows... so I guess they found some way around the problem?
I'm sure if my car didn't have godawful emissions it wouldn't bother me as much but right now it's pretty unbearable.