I have a a gas stove in the kitchen that seems to work well. Just as they start to glow is plenty.

I bet compressed air on the 'in ' line would shoot that seal across the room. The rest are rated for 100+ PSI.

The mainshaft seal? Somebody should try this!

how important is it to replace the heat shields when cleaning injectors? the green book says to do this.

You don't trust the greenbook?
 

Heatshield seals injector nozzle face to cylinder head by way of getting deformed (compressed) between the two during installation. Also allows heat transfer from nozzle end to head (which itself is cooled by circulating coolant). Compare a used one to a new one and you will see the extended inner section on the new one is compressed flush with the outer section on the used one.

As such, heatshield is a one-shot deal, not likely to seal as well on second use.

Don't make your problems worse!

Theoretically there is a way to re-form them using a ball bearing and visegrip pliers with a welded-on flange. Anyone here tried that?

I can see how they are flattened out. I found a thread on a VW site that had some nice clear pictures of new and used ones.

It looks like these may have been reused in this car before as there is a buildup of soot on the injector threads. Is it necessary to clean this out? I don't want to risk having that debris get into the engine. What makes a good plug?

Clean it, and the seat face. If the seat t face gets eroded away, the head is pooched.
I've cut teeth on an old heat shield to clean bad ones.

So I found tiny rubber plug and am proceeding to clean out the injector threads and cylinder areas. What a dream to work on the back injectors and glow plugs without the pump in!

I tried the ball bearing thing to re-form the heat shields using a little arbor press, it seems to be working!

I am hesitant to put the pump back in without testing it somehow. Was it in this forum where someone said if you turn pump shift with a drill, fuel will shoot out the manifold "like a machine gun"? I couln't find it. Do I just run the 'IN" line to a fuel can and turn the shaft with a power drill?

OK I just discovered something that really threw me. Injectors 5 and 6 have really small (~3/16") hole in the block under where the heat shield sits. #4 has a gaping (~1/2") hole ! I can see the glow plug tip! What gives?

carbon, or there is another heat shield lurking under there?

if there is any erosion of your heat shield faces, don't reuse them.

You need a bad boy drill to even turn it, and the result still won't mean much. Pressure test 15-20 PSI if anything.

not carbon or another heat shield, but definitely a metallic washer under where the cylinder head decreases in diameter. I took a nice pic showing #4 and #5 with injectors pulled. How can I post pictures?

BTW I found new heat shields at O'Reilly's, special order but next day to store. Surprising. Parts are typically hard to come by out here in the SW.