[Vwdiesel] More Quantum questions?

LBaird119 at aol.com LBaird119 at aol.com
Tue Oct 27 22:29:09 PDT 2009

  Older MB's used the series glow plugs and even had one in the 
dash (sort of) that glowed orange when it was hot so you really 
knew how long they were glowing.  The later ones are 12v, normal 
glow plugs like you're used to seeing.
  The easy way to test a glow plug is to disconnect the buss bar and 
connect a test light between battery + and the power connection of 
each glow plug.  If the ligt lights then the glow plug is most likely good.
Some will light up a light but not glow properly, such as glow on the 
side, part way up, very slowly, etc.  Those generally are on their 
last legs but not always.
  I agree it sounds like you have an air leak in your system.  The 
most common place is on the return side.  The large hose from 
the pump banjo to the return hard line is usually good for about 
15 years before it starts to look slightly wet or dark, dirty.  They 
start letting air in a year or so after that starts.  The small 
return hoses can leak, I've seen the nipples on the injectors 
cracked, fuel can leak on the high pressure lines and between the 
injector halves but that usually won't cause air in the system.  
ANY inlet side hose connection is a possible culprit for letting air 
into the system and the hose clamps should be checked. If the 
clear line gets bent or kinked, it can crack a pinhole that will let 
air in but not fuel out.  I've had just about every one of these 
problems and most were at one time on the Rabbit!

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