Checklist for Reliability of Older Audis

[Marc Boucher]

Hi Cody, this was an excellent post.  In addition, Huw added in a separate 
email,

"Do all the vacuum hoses sometime.  Undo all the electrical connectors, clean, add dielectric grease, and reassemble sometime.  Do the entire cooling system (hoses, stat, heater core, water pump) on your next timing belt change.  Pull all your fuses, clean, replace. Spend $500 and rebuild the entire fuel pump/filter tray (wait, you have a 100, right?  Pump in tank, filter in engine bay, never mind, on my cars they are in the LR wheel).

Questions based on these comments and the email below:

1.) Dielectric grease is used, if I recall, to help conduct heat between (for example) a power amp and its heat sink.  Its an electrical insulator.  Did you mean something else when you said to "Undo all the electrical connectors, clean, add dielectric grease, and reassemble? "

Whats the best substance to put on electrical conductors to ensure that they keep conducting?  In other instances I've used "electrical contact cleaner", which is essentially aerosolized alcohol and heptane.  Its good for cleaning contacts, but leaves no residue.  Is there something thats good for preventing the audi glitches that come from oxidized contacts, such as WD-40?  Everything from the "power-window switch syndrome" to this current case of "ground signal from ECU not working" 

2.) You mentioned, "on your next timing belt change".  How often should a timing belt be changed in an I5?  And are there any symptoms of a worn timing belt that usually occur before the belt actually slips?

3.) Below was mentioned that you always travelled with "a spare ignition switch".  I've read that these are failure prone.  The question is, on the road, would that be a simple repair assuming you've got the tools?  Wouldn't it involve pulling the dash out?

4.) It was commented that Audi Bosch coils essentially never go bad.  But I've also read that the Beru coils were an improved electronic design from the original cylindrical Bosch, in the same way that the Piersburg fuel pumps seem to do better than the original Bosch fuel pumps.  Any opinions?

MC



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From: "Cody Forbes" <cody at 5000tq.com>
Sent: Monday, August 15, 2011 11:10 PM
To: "Marc Boucher" <mboucher70 at hotmail.com>
Cc: <quattro at audifans.com>
Subject: Re: Checklist for Reliability of Older Audis

> Electronic parts tend to fail suddenly. At one moment the trace on the PCB 
> or the resistor or whatever is good, the next minute it burns out and it 
> stops working. There's not much way to ever tell if it's going to go bad. 
> Its like the surprise mother in law visit, one minute life is good, the 
> next minute you hear the door bell and its all gone to crap. You could 
> simply replace EVERYTHING, but with the quality of Chinese replacement 
> parts you don't even know if the new part will last longer than the 20 
> year old German part (non-OE ignition switch for example).
>
> The fact of the matter is that by now a large number of the owners of 
> older Audi's (us) are either mechanics, very experienced at fixing them 
> ourselves, and/or carry a decent number of spare parts in the trunk. I'd 
> bet the majority of us have more than one of whatever model we like (How 
> many 80/90's does Huw have now?) so we can have a large chunk of spare 
> parts neatly stored in a sort of weatherproof car shaped storage bin or a 
> fully operational spare to use when the other one breaks. Personally I 
> cover my bases by being a professional Audi mechanic, owning not one, not 
> two, but three of the same model year 5000tq's, AND having a mini storage 
> unit that is part 914, part boxes of encyclopedias, and part Audi 5000 
> door handles with some other spares for good measure.
>
> If you want to be covered go find one of your car in a junk yard. Take 
> every component between the battery and the spark plug (ECU, relays, coil, 
> igniter/power output stage, distributor, etc). First test them on your 
> car, then put them in the trunk under the spare tire. Then go buy a brand 
> new ignition switch electrical half, distributor cap, rotor, and plug 
> wires and put them in the trunk too. Add a few fuses, a Bentley manual, 
> maybe a belt, and a roll of duct tape and you should be able to solve 
> almost any problem on the side of the road that is ignition related. In 
> normal car circles that may read like a joke or very sarcastically, but 
> I'm actually not kidding. You simply never know and with those things the 
> likelihood of being stranded needing a tow is pretty low.
>
> My trunk spares bin is not that large, but each of my running two 5000's 
> does include a tool kit, a spare ignition switch, **latex work gloves**, 
> engine oil, CHF11S, and duct tape. Anything else I balance the risk 
> against the fact that I might McGuyver something or just get a ride to my 
> warehouse of spares. For long trips I either take my A8q which has less 
> years and less miles (yet vastly higher broke parts to miles traveled 
> ratio) so my butt is comfy when I'm waiting on rescue or I take my 5000 
> that has a custom built electronic fuel injection system and 
> coil-per-cylinder ignition so that I'm certain that if it breaks I won't 
> be able to fix it because it's all one off unique parts that I made myself 
> and the only other part like it on the planet is hundreds of miles away 
> back in my tool box.
>
> In the end, just do the usual maintenance and don't sweat it when 
> something unexpected fails. 80% of the time there's zero possibility of 
> diagnosing something that isn't broken yet. It is an old car and things 
> will fail, but it really does tend to be fairly few and far between. The 
> very very best thing to do is learn about the car and how to work on it so 
> you can figure these things out on your own. Then next time you might 
> figure out what's broke and walk/hitch a ride to a parts store and fix the 
> thing right then and there.
>
> -Cody (mobile)