[Vwdiesel] head gasket done but temp gauge still creeping up.

[Doyt W. Echelberger]

Hello Will....I'm seeing a generally similar story with my 1985 Jetta 1.6 
TD, except for the absence of a sandwiched gritty oily zip tie or a ding in 
the head.

About 6 months ago, it boiled over, burst several hoses, and blew out all 
the coolant.... this after months of oil streaks showing up in the coolant 
overflow tank.   We pulled the head and examined the old gasket and saw 
evidence of leakage.  We replaced the head gasket and used new head 
bolts.  It ran normally for a month, then started showing bubbles in the 
coolant.....which tested positive for exhaust gases.

We retorqued the head bolts and the bubbles stopped. We replaced hoses and 
the pressure cap on the plastic overflow tank.

Now it starts normally, warms up, but early in the trip the temp gauge 
rises to the danger level...this only involving flat driving. To avoid a 
catastrophe, we immediately shut it down and let it cool off. An obvious 
problem showed up....the fan wasn't coming on to cool the radiator. So we 
fixed the fan problem.

We replaced the thermostat and the fan sensor that goes in the side of the 
radiator.
Now the fan comes on, but the heat problem is still there. The coolant temp 
just keeps rising past normal after the thermostat opens up.  It is heading 
to the top dot on the dash gauge. So far it hasn't boiled over, but we 
haven't pushed it very far.

We are afraid to drive it in that condition, mainly because the roads are 
so icy that there is no place to pull over if it becomes necessary. Three 
foot drifts everywhere.

The bad weather gave us time to think about some possibilities.  One 
explenation is that the coolant sensor in the block is faulty and is giving 
an overly high reading, so when the weather permits we are going to use a 
hand-held laser thermometer to verify the actual temperature at the sensor 
housing when the dash gauge shows the high reading.

That pretty well describes where we are at the moment. Work is paused 
because the car is sitting outside our house, 12 miles from the shop, and 
the area is experiencing an Alberta Clipper that makes driving hazardous. I 
may not get the car to the shop for another few weeks. You probably have it 
even worse in Alaska.

Good luck, and keep telling us what you find.

Doyt
Ohio USA



 >>>>>>>>>>>>>>>>
At 08:58 PM 1/29/2009, you wrote:
>94 Jetta with 1.6TD (originally 8v)
>
>HISTORY:
>
>Massive overheat, lost most coolant, air just boiling out of overflow,
>pulled head, full head job done at independent VW shop.
>
>(Obvious crack in gasket from #1 cylinder to coolant passage.)
>
>Cleaned bock with the white 3M rotary bristles and engine
>degreaser/brake cleaner.
>
>Block had significant pitting near the coolant passages where the fiber
>part of the gasket touches, metal contact surfaces looked good.
>
>Dinged head when transporting home, also stupidly had a gritty oily zip
>tie sandwiched in-between head and block when starting to tighten down.
>
>Used ARP Cosworth studs torqued to 85, broke and retorqued 3x: 40-80-85.
>
>Timed to 1.01mm, runs great, sounds like marbles when cold-start is out,
>almost all the marble sound gone when pushed in.
>
>I've got a veg-kit with extra coolant lines running to the trunk, tried
>to purge these as well as possible.
>
>Routed head to top of radiator hose UNDER veg lines when first started.
>ooops.  The vent to overflow sphere doesn't work when it has to flow
>down.  Started to overheat, shut it off, cooled it down, routed head to
>radiator hose at ON TOP of system, blew some bubbles out, after 5 miles
>things seemed to be perfect.  That overflow hose really likes to be up
>high to purge air.
>
>THE PROBLEM NOW:
>Car is acting like there's bubbles in the system, gets to normal
>operating temp, goes up one tick - especially on uphills, goes back down
>on downhill coasts.
>
>When overheating (I'm running with the coolant cap off - thinking there
>is air in the system - I've tried with cap on, and it's similar) the
>coolant bubbles up out of the reservoir.  While driving this isn't so
>much of a problem, but fiddling with the system when parked I can do it
>every time.  Is this standard on getting hot?  I'm thinking it's a sign
>of air in the system.
>
>There's not really significant air coming from the overflow hose,
>occasional foam (I took the restrictor out to see if that make it purge
>better), it seems to be pushing quite a bit of fluid.
>
>The OEM water pump, aftermarket radiator and OEM thermostat are a year
>old.  It always got hot on hills, but not on flats or while idling.
>
>I'm thinking of running a compression test (check the head gasket) and
>swapping out the thermostat - could overheating have damaged the
>thermostat?
>
>I'm fearing that my gasket job, while making the car drivable, may have
>to be repeated (and I'm doing this in the neighbors garage.....eeeek!)
>
>Will in Alaska.
>
>
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