Bought a 94 Passat, how to tell if TD or TDI and other Qs

[QuickTD]

Yours may well have been fixed once, or it may have just been looked after. I have seen the odd one make it to 300000+ without intervention, but its fairly rare.

 As for an early warning, I wouldn't count on it... Some just wear the key  without really loosening the bolt much, the pulley will then "cam" outward over the worn stub of the key and snap the bolt off quite suddenly. If you don't know the history it might not be a bad idea to change the timing belt and have a look at the pulley while you're in there.

[commuter boy]

 The "umwelt" isn't as nuetered as the older 1.6 ecodiesel. The LDA on the pump is present, but the factory aneroid pin and spring combination really doesn't add much fuel under boost. It also does not add fuel in a linear fashion, its more of a 2 stage setup. With a proper aneroid pin and spring the engine will really wake up.

Are you sure about that?  Mine doesn't have the "mushroom" on the top, and no connection to the turbo at all, same as his.  Just a blank plate where the LDA should be.

[QuickTD]

Are you sure about that?

Look closely at the image in Lum's post, you can quite clearly make out the banjo fitting on the rear of the LDA cap with a hose running from it over the valve cover. In another image you can, perhaps not so clearly, see the hose running from the banjo fitting to the elbow on the intake manifold. The AAZ LDA does not have a screw to adjust the base position or "off boost" fueling, but it does nonetheless have limited boost enrichment. Mine has the same pump, I'm currently running and LDA pin and spring from a BMW 524TD pump, works nicely.  

 I have seen one AAZ pump that did not have an LDA. A photo of it was posted on this, or maybe another forum. I believe it was a very early passat. It had a completely flat plate fitted over the LDA lid, possibly the same as yours?

 There may be a few variations on the AAZ, some more common than others. Suffice to say that Lum's, as well as the great majority of others, are fitted with some form of LDA.

[Lum]

Well, I think I'm going to stop driving the car for now, then when I get paid I'll take it in for a service, get all the belts done, and ask for the crank timing pulley/bolt to be replaced as well.

Anything else I should know about this engine so I can get it done on Wednesday?

[Maarten]

It's that rare bird, the 1.9 AAZ Eco-Diesel ("Umwelt").

The AAZ is the "succesor" of the 1.6 ECO diesel, hence the crippled fuel enrichment and small turbo. Shortly after that the TDIs came around for replacing the 1.6GTD while the AAZ was still sold till '98.

It does have 2 spring bodies.



A picture of the old&new style bolt, if you have the old one.. DO NOT drive it until you have replaced it!

Lum,. a mile is roughly 1.6km, 220k =352K Km

[ricosuave]

the proper phrase should be

do not RUN it until youve replaced it

[commuter boy]

I stand corrected, his does have the LDA.  So it's not an Umwelt then, like mine.

[Lum]

Well, it's going in for a service tomorrow (hopefully) so I need to figure out what to get them to do.

20,000 mile service
Check belts, but they look fairly new
replace crank timing pulley and bolt with a new style one (see picture)
Fix alternator belt tension
Fix slack in throttle cable and lubricate where necessary
Replace the two silver fuel hoses in the engine bay with the correct kind of hoses (clear?)

Anything else I should be getting done?

[Lum]

Ok, it's at the garage now, being serviced.
He's told me that the crank pulley looks ok, and that the bolt was tight, though hasn't told me which kind of bolt it has.

Is it possible to replace the bolt with the new kind? If it's the old kind should I be replacing it even though it was nice and tight?

[QuickTD]

The bolt must be replaced if it was removed, it is a stretch bolt. Make sure the mechanic understands and follows the torquing procedure and uses the new style bolt. I would replace the pulley as well, just for insurance. The new bolt must be tightened to 66ft/lbs and then tightened a further 90º. This is far tighter than most impact guns are capable of. Your mechanic may need to come up with a method of holding the crank stationary while tightening the bolt. I use a homemade tool that attaces to the pulley face, but pulling the oil pan and blocking the crank with a wood block also works. The clutch/brake method will not hold the crank, the clutch slips before you get the 90º turn on the bolt.

[Lum]

I think he just inspected the pulley and tested the bolt TBH, are you saying this isn't enough?

It's going to have to go back soon for a little more work (the fuel pump needs replacing (and I'd like to know if it can be upgraded at this point, the brake hoses and suspension bushes need doing, and also a wheel bearing) so I'll get this done then.

[Lum]

Does anyone have VW part numbers for the pulley and the bolt because the guy at the parts desk at the VW dealership had no idea what I was talking about and just gave me an exploded diagram and suggest I get you people to point out which bits I need, which would be fine if I had a scanner.