[Vwdiesel] Overheat on uphills - help with diagnosis.

[Will Taygan]

Arrgh!  My first thought is head gasket, but I'm trying to think of
other problems too.

1994 Jetta with 1.6TD, ACN tranny and Plantdrive-like vegoil system in
Alaska.

All last winter the heat would barely stay warm, temp pegged just above
the 160F mark.

Had the TD Injection Pump rebuilt last winter, shop returned settings to
specs, previously they were turned down as it likes to send black smoke
on moderate turbo acceleration (fueling turned back up).  

It always overheated on the long mountain passes, I assumed from this
rich fuel and a weird tranny/body/engine combo.

Water pump went out last winter, did not overheat, had a new pump put in
at the neighborhood shop.

I discovered the PO had cut a hold in the expansion cap, so it doesn't
hold pressure.  I switched out the cap for the one on the 91 ecodiesel,
so now it works.

Installed a mostly Plantdrive SVO system, tapped a loop into the heater
lines and forgot to fill the new lines with coolant (7th vegoil
conversion, getting cocky.)

Overheated on the highway, boiled over, got to a gas station, spent an
hour with the expansion cap off pushing the acceleration lever in and
out burping bubbles.  Finally burped it all out.

I put in Sierra coolant (propylene glycol - less toxic and
aluminum-friendly).  I wondered if the shop put in regular green
ethylene glycol, and thought maybe there was to high a concentration of
antifreeze to water, so I drained the radiator by pulling the lower hose
and put in distilled water.

Bad idea. Overheated and boiled over again, added lots of water and a
tiny bit of coolant.

Car is now overheating (well, not boiling over, but between 2nd and
middle tick, where usually it's below the 2nd tick) on the flats,
significantly on hills (even just parked idling with the nose up) and
cooling down on the downhills.  I can drive to town if I crank the heat
up to high and roll down the windows.

No oil in coolant, no pressure in expansion tank in the first minute of
startup, oil weeping from head gasket under #3 injector.

Top radiator hose gets hard on acceleration, coolant dribbles into the
expansion tank on acceleration, not burping anything additional that I
can see.

Could crap have blocked something when I cut into the system? Head
gasket? Bad water pump?  Radiator? Aargh.

I have an 82 parts truck that I was going to pull the head and bring it
into a shop so I don't have to leave the Jetta for a few weeks, but
don't want to replace the head if that's not the problem.

I can't do a compression test unless I remove the IP, since the aneroid
block the socket on #2, but I need to do a timing belt anyway, I'd
rather have a head ready to pop on, if that's the problem, rather than
do the IP twice..

Help!

Will Taygan
Chugiak, AK
81 1.6NA pickup
82 1.6NA parts pickup
91 1.6Ecodiesel Jetta
94 1.6TD FrankenJetta