QTC: Starter issues

[steveb@falcon.kla.com (Steven Buchholz)]

Rich posted a message about a hot starting problem where the starter will 
not engage on his urQ when the engine is very hot, but works when the 
engine cools down a bit.  This is certainly a problem that I am familiar 
with!  I meant to reply to the post sooner, but I had some problems with 
my e-mail and such ... so I thought I'd post my observations WRT starters 
to the list.  I have managed to reduce the frequency of occurrence without
having to change the starter ... but I'll probably bite the bullet soon.  

As RDH (I *think* it was Robert) posted, you should be able to solve your
problem by replacing the starter.  There are a couple of other things that
might be able to resolve your problem.  

The first and easiest (?) would be to ensure that the starter is shielded
from the heat of the exhaust/turbo.  As best I can tell on my car a pre-
vious owner replaced the starter with a rebuilt unit.  The size of the 
replacement starter was different than the OEM, so the OEM heat shield no 
longer fit ... so they left it off.  When I looked at the starter on the 
'88 5k I saw a more flexible insulated unit that attaches over the solenoid,
and is held in place with a large hose clamp.  I have bought one of these 
and found that it will fit over the solenoid on the replacement starter I 
have on the shelf.  I suppose I ought to install the thing on the current 
starter to see if it helps ...

The second issue is the electrical supply to the starter.  I have found that
I can get the starter to engage in hot situations by hooking the starter 
motor's hot lead directly to the solenoid pull-in lug.  There is a VW Tech 
bulletin that describes installation of a "load reduction" relay between 
the ignition switch and the solenoid.  As the starter switch contacts age 
the contact resistance increases, with an associated increase in voltage 
drop.  I actually had some success when I replaced the ignition switch 
module (which is quite an experience in and of itself!), but it was short 
lived.  Marty@Carlsen was selling some wired up relays as a side enter-
prise ... I don't know if he is still doing it, but I believe that this mod
will add a lot of robustness to the starter system.  The thing I don't know
is how much life the starter would have from that point on.  IME I've had 
the hot start problem on and off for a couple of years, and the starter 
doesn't seem to be getting any worse.  

I actually have a replacement starter sitting on the shelf, but when I 
crawled under the car I found it quite difficult to get to either of the 
mounting bolts.  Does anyone out there have any secrets for that?  I think 
I can get at the bottom one by jacking up the motor a bit, but it seems 
like I'm going to need some kind of universal joint equipped setup to get 
up to the top bolt ...

Let me know if you need the part numbers for the heat shield.  As usual I 
don't have the info sitting right in front of me, but it can be easily 
obtained.  I will be installing the relay and heat shield when I replace 
mine ...

Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)