Date: Tue, 27 Apr 2004 13:23:37 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: Summer's coming and my van is getting hotter than ever!!
In-Reply-To: <0HWQ00L68EL0IR@dedicated59-bos.wh.sprintip.net>
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At 09:51 AM 4/25/2004 -0500m John N. Motlagh wrote:
>You never notice how hot you are running, until it starts to heat up out
>side. So let me drop a couple of problems on the list, and see who pick
>them up.
>
>1. The 86 2.1 runs temp gauge runs with the needle about 2/3 high, the
>fan will come on and bring it down a bit, and then it stabilizes. At this
>point I can turn the front heater on, and the temp takes a dive, about 1 or
>two needle widths below the LED. Is this normal behavior?
No. Smacks of bad thermostat to me -- the gauge behavior is internally
consistent and I suspect it's telling the truth -- the giveaway is the
sharp drop to below normal when you put the heater on, suggesting the 'stat
isn't controlling the system at all. The radiator could be plugged up as
well, but that wouldn't by itself explain the drop to below normal.
> I can put up
>with the warm tootsies for now, but I don't know if anyone has spent the
>summer in Dallas.
I spent a week there once at the Crystal Palace replica -- 60F when the
plane landed, 35 when we reached the gate, 15 next morning. Everyone
walking around dazed, nothing worked. I got to set up our stuff right next
to an 18-wheeler-size (the whole truck, that is) loading door that
naturally was wide open with the wind whistling through. Every time I
touched the gear I'd draw a giant spark but the systems never
hiccoughed. We had overheating problems -- not that week -- but not
static. Hmmm...I guess that wasn't summer.
>2. When I first turn on the van the blinking temp light comes on, and
>stays on until I stop and restart the van. It doesn't seem to matter how
>warmed up the van is. Thoughts on this?
Stop and restart -- that's the key clue, though I don't know offhand why it
works that way. Anyway, quite likely that the big electrolytic cap inside
the gauge is leaky. That cap is supposed to charge up and stop the
blinking after a few seconds, but it's a high-impedance circuit and doesn't
take much leakage to, um, foil it.
Short the sender wires (unplug and jumper) and try again. If the light
behaves normally, i.e. blinks a few seconds and stops, problem is low
coolant or crud on sender electrodes or bad contact at the plug or bad
mixture. It needs to see a resistance of less than ~180k across the sender
pins to shut off the light. While you're there clean and dry the plug if
there's any doubt, as it doesn't take much leakage to shut off the light
permanently.
If it still blinks, highly probable IMO, pull the controller module -- if
my memory serves it's the third from the left on your strip of relays, with
#19 painted on, but check your Bentley. If it blinks after that, it's
either a bad gauge or bad supply voltage to the gauge (10.0v +/- 0.5). You
can fix the gauge if you're handy -- if you look at
http://pws.prserv.net/synergy/Vanagon/Gauge_adjust.htm that's the
mechanical innards of the temp gauge (I'll put up some pictures of the
board later). The circuit board is soldered to two of the three posts,
component side facing into the gauge. Remove it and the connections to the
gauge heater, replace the electrolytic cap with an equal replacement (use
tantalum even if the original is aluminum) observing polarity. Exact match
isn't necessary; 10 uF will give about three seconds, 15 uF about 5. On a
quick test, none of the small aluminum caps that I've had lying about for
years would stop blinking; all the tantalums (same age) I tried
would. Clean the flux off the board carefully and put it back together,
should be ok. I think #2 machine screws will fit the faceplate holes.
While you have the gauge apart is a good time to change to a bright LED...
>After reviewing the archives, I have found three cheap (and I like the way
>this sounds)
>
>1. Flush and fill, but what mix for the summer? 50/50 (coolant/water)
>or 60/40? What brand for the van?
VW sez use 50/50 unless you need richer for very cold weather, not
likely. Prolly good thing to do since it likely hasn't been done in far
too long.
>2. Replace the Temp II sensor
No relation to the gauge or to engine temp. It informs the ECU of engine
temps and will usually cause a hideous rich condition if it fails or has
bad connection.
>3. Replace the reservoir cap
Umm...why? Are you overflowing the overflow tank?
>1968 Golden Westy
I'm assuming that's an '86 -- if not then you'd prolly better consult
whoever did the watercooled conversion... <g,d&r>
david
