Home Technical Discussions Volkswagen Vanagon: 1980-1991 (T3)

Volkswagen Vanagon: 1980-1991 (T3) 1985 Vanagon -- Overheating


Permlink Replies: 12 - Pages: 1
Last Post: Aug 26, 2009 1:50 AM Last Post By: quigleyp
VannieAnnie

Posts: 7
Registered: 04/22/04
1985 Vanagon -- Overheating
Posted: Apr 22, 2004 2:00 PM
  Click to reply to this thread Reply
Thanks for the earlier reply about my cigarette lighter. My Bentley manual is on order. This forum has been so helpful -- I've already learned a lot.

This is a different post for a different problem. I took my 85 Vanagon on the Interstate today, and I was happy with my speed and power. Unfortunately, I drove into an accident area, with a long backup and bumper-to-bumper traffic. I live in the mountains of NC, and of course, I was trying to climb a long hill.

My temp guage got higher and higher. The car stalled, I had trouble restarting it, when I was finally able to get it out of traffic and stopped against the guardrail, smoke was coming from the engine and the heat warning light was blinking.

I opened the engine lid and let everything cool for about thirty minutes and then was able to restart the car and get off at the next exit. Some coolant had spilled on the pavement, but it wasn't a lot, and the tank level was still within range. I drove it another 20 miles, ran into a construction area where traffic was again backed up, and again, my heat indicator got higher and higher. This time, it didn't smoke or blink, so I was able to get home without a cool-off period.

I bought this car from my long-time, trusted mechanic's lot, and I have a receipt for head gasket replacement that he did. The car has 150,000 miles on it, and runs smoothly on the open road. I've driven VW's for thirty years, but I've already learned that the Vanagons are specialized in many ways -- especially with the cooling system.

The owner's manual cautions about overheating, but says that unless the blinking light comes on, that some overheating is not dangerous.

The coolant level looks okay. Is stalling and overheating something that often happens with Vanagons in bumper-to-bumper traffic, especially climbing hills in first gear, or is there something else that I should look at? I'm worried, becuse it's still spring here, and I wonder if summer heat will be worse?

Thanks for any help.
wohlfarth

Posts: 1,744
Registered: 10/31/03
Re: 1985 Vanagon -- Overheating
Posted: Apr 22, 2004 2:13 PM   in response to: VannieAnnie in response to: VannieAnnie
  Click to reply to this thread Reply
The first question that pops into my head is whether the high speed cooling (radiator) fan was in operation during this overheating. It's usually pretty obvious as the high speed fan is much noiser than just the regular speed fan. If the cooling fan isn't automatically kicking to high speed on warm days and while the van is sitting in traffic, then this might be the problem.

Another thing to check for is whether the coolant is bubbling in the reservoir after the engine is fully warm. This would indicate a head gasket leak (air getting sucked into engine around the failed head gasket).

If the cooling system is operating properly, the van should not stall or overheat in traffic.

-Stan
VannieAnnie

Posts: 7
Registered: 04/22/04
Re: 1985 Vanagon -- Overheating
Posted: Apr 22, 2004 2:41 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
I never heard any change in the fan noise, so I'm guessing that it never changed from normal speed to high. What sensor or control causes an increase in fan speed?
wohlfarth

Posts: 1,744
Registered: 10/31/03
Re: 1985 Vanagon -- Overheating
Posted: Apr 22, 2004 2:59 PM   in response to: VannieAnnie in response to: VannieAnnie
  Click to reply to this thread Reply
The thermo-switch for fan which is located on the radiator (upper right front corner) controls the fan. The high speed fan (stage II) should come on when the coolant temp. reaches 210-212F and go off when it cools down to 196-206F. This information came from page 19.12 of our Vanagon manual.

Check and see if there is excessive corrosion on the electrical contacts of the thermo-switch or harness connector at the switch. This might be the problem, or the switch might just need to be replaced.

-Stan
TomB

Posts: 1,385
Registered: 08/06/02
Re: 1985 Vanagon -- Overheating
Posted: Apr 22, 2004 3:57 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
It doesn't sound like a head gasket leak, as that usually blows coolant out without overheating - just adds pressure to the cooling system.
When all is working right a Vanagon does not overheat. Ours always stayed mid-range even in city traffic jams at 110F in Texas summers - until either of a couple problems occurred.
The radiator fan not running is the usual culprit. I'm not sure about the 85, but the later vans have a "load resistor" behind the driver's headlight that is used to get the different fan speeds. This big resistor eventually cracks the ceramic coating, exposing the wires, which burn through and you lose some fan speeds. It can be the thermostat switch in the radiator, but that isn't as common.
Since the heads have already been "fixed" (expected every 5-7 years due to corrosion), the radiator may well be clogged with corrosion sludge from the old heads. Once this happens it no longer cools effectively. Usually a "flushing" doesn't help much, but replacement radiators from busdepot.com or vanagain.com are pretty reasonable. I've replaced them on two vans and completely eliminated any overheating.
VannieAnnie

Posts: 7
Registered: 04/22/04
Re: 1985 Vanagon -- Overheating
Posted: Apr 22, 2004 4:30 PM   in response to: VannieAnnie in response to: VannieAnnie
  Click to reply to this thread Reply
Thanks for all the replies.

I found one possible solution: fuse #7 which controls the radiator fan on my van was bad. So I replaced with a 16 amp fuse.

Obviously, the fan can't cool if the fuse is blown.

But I don't know how long the fuse was bad -- would overheating have shown up in short trips? Now, the question is what caused the fuse to blow? Could I have damaged something by running with no fan?
Bodhi

Posts: 1
Registered: 12/29/04
Re: 1985 Vanagon -- Overheating
Posted: Dec 29, 2004 10:22 PM   in response to: VannieAnnie in response to: VannieAnnie
  Click to reply to this thread Reply
Hello. I have a similar situation occuring at the moment with my 1987 Vanagon. The warning lights have started to blink however the temperature needle barely moves at all, not even out of the bottom white box. I had the gaskets replaced about 2 months ago and they are solid, no leaking underneath the engine of any liquid, and both reservoirs are at good levels. Could I have blown a fuse as well? I am not sure what the problem is.
sicotaman

Posts: 5
Registered: 11/22/04
Re: 1985 Vanagon -- Blinking Light
Posted: Jan 1, 2005 10:51 AM   in response to: Bodhi in response to: Bodhi
  Click to reply to this thread Reply
Here is a link that describes the "blinking temp. coolant light" problem and it's solution from "Roadtripin" at FMBC.

http://www.fullmoonbusclub.com/modules.php?name=Forums&file=viewtopic&t=890
divebus

Posts: 1
Registered: 04/28/08
Re: 1985 Vanagon -- Overheating
Posted: Apr 28, 2008 12:26 AM   in response to: VannieAnnie in response to: VannieAnnie
  Click to reply to this thread Reply
Chances are the low speed fan resistor is bad. It may have been only on air conditioned cars, but check anyway. Remove the driver's side headlight (U.S.) and find a large green resistor with three wires on it mounted to the car's sheet metal on brackets. My resistor used to blow all the time and then only the high speed fan would run during overheat.

The resistor is something like 1 ohm with a tap in the center. I replaced my resistor with four 12v headlamp bulbs, two pairs, each in parallel, wiring them to electrically replace the resistor. The low speed fan now runs a little faster than it used to and the lamps act as resistors which won't blow out. They glow dimly while the fan runs and my overheating problems are gone.
islandbus

Posts: 1
Registered: 08/02/08
Re: 1985 Vanagon -- Overheating
Posted: Aug 2, 2008 6:02 PM   in response to: divebus in response to: divebus
  Click to reply to this thread Reply
I have 1991 Vanagon and the load resistor for the cooling fan is bad, the one behind the drivers side headlight. It would be so cool if you would give me more detailed info on the fix you posted so I could confidenty make the same thing you made for your divebus. Thank you so very much, islandbus
FKH161

Posts: 7,626
Registered: 12/29/05
Re: 1985 Vanagon -- Overheating
Posted: Aug 4, 2008 1:47 AM   in response to: islandbus in response to: islandbus
  Click to reply to this thread Reply
BUGGSY

Posts: 208
Registered: 11/04/06
Re: 1985 Vanagon -- Overheating
Posted: Aug 4, 2008 1:37 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
First of all, the fuse you replaced should be 16 amps.
Red in color. Secondly, test the reistor before
replacing by removing the lower grill. On the lower driver's side of the radiator you'll find your thermo switch. There will be a wire connector plugged into the switch. Pull the plug. If you have A/C installed, there will be 3 wires, if no A/C there will be 2 wires and no resistor pack. Check that current is present at the plug,
red/white wire. Jump the red/white and red/black terminals. The fan should cycle in the lower speed. Next,
jump red/white and red/blue, the high speed should cycle. If no to one or both, the resistor pack is bad.
If the fan cycles in both instances, replace the thermo
switch, not the resistor pack. However, if the fan cycles normally, and you're still overheating, you've
got other problems such as a partially restricted radiator, faulty thermostat, or maybe air pockets in the
system.
Buggsy
quigleyp

Posts: 1
Registered: 08/26/09
Re: 1985 Vanagon -- Overheating
Posted: Aug 26, 2009 1:50 AM   in response to: Bodhi in response to: Bodhi
  Click to reply to this thread Reply
I am having this exact problem...what happened to your Vanagon?

Point your RSS reader here for a feed of the latest messages in all forums

Popular Discussions:
No popular dicussions.