Could also be a cracked head or block.

Dennis,
From my phone.
________________________________
From: Steve<mailto:loudmouth_70@YAHOO.COM>
Sent: ‎12/‎31/‎2013 3:57 PM
To: vanagon@GERRY.VANAGON.COM<mailto:vanagon@GERRY.VANAGON.COM>
Subject: Overheating

Vanagon Listers:

I've got an 82 diesel, she's overheating.  On 5 hour road trip, after hour 4 started blowing cold air then back to hot, then cold again.  Soon the needle raised up and light flashed.  Had extra coolant with me, while topping off expansion saw that the cloth wrapped hose to fill tank had come off.  Replaced and gingerly made it to destination.  Stopped three times to let cool.  I figured I'd gotten air into the system and needed to bleed it out.  I've done that today--with little success.  Got it up to temp, parked on a ridiculous incline to get the air up to the radiator.  Not much hissing.  After 8 attempts only once did coolant bleed out.  Air continued to blow mostly cold with heat cranked, occasionally while driving around it warmed a little.  Needle would raise at low RPM's then return closer to the middle when I revved it up.  Even at slower speeds with engine revved it would cool--that confuses me a bit as little air is moving over
 the radiator--makes me think it'd be hotter.

I'm wondering about two things: first what's likely to be the cause of this behavior?  Secondly, any tricks for getting me home before starting these projects?

I'll be leaving Friday, I'm at Lake Chelan in WA, little town of Manson to be exact.  My gut tells me Radiator for sure, pretty sure it's the original.  Not sure about thermostat or heater core.

Happy New Year, appreciate the advice.  Nothing like bringing in the new year with a little repair work.

steve