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vanagonforever Samba Member
Joined: July 29, 2007 Posts: 211 Location: Baltimore, MD
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Posted: Wed Aug 27, 2008 10:34 am Post subject: Crazy temp sensor? |
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I have another problem that just cropped with my van that I'm not sure what to do about. Occasionally when I start the van my temp gage will rocket all the way to super hot and the light starts blinking. There is no way that the engine could be too hot because it only happens right when I turn it on. After driving for a mile or two things settle down and the gage returns to a normal level. I was thinking maybe its a wiring problem but I just thought I'd see what you guys said before I dug too far in.
Thanks! _________________ 1986 2WD 2.1L WBX Vanagon Weekender
1983.5 1.9L WBX Vanagon Westfalia |
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deprivation Samba Member
Joined: September 14, 2006 Posts: 1220 Location: Austin, Texas
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Posted: Wed Aug 27, 2008 12:19 pm Post subject: |
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Sure, could be wiring. But offhand I'd look at coolant levels or possibly, at worst, a dumpy water pump. You might have a monster air bubble in your coolant pathway, too. Since the gauge goes ga-ga before the engine is actually hot this could also be a bad sender.
There's also a sender in the coolant tank itself that flashes a warning if your coolant level is too low.
The temp sender isn't too hard to replace on the 2.1 and I imagine it isn't too hard to replace on the 1.9. So, you may want to bleed your coolant system and then check (or replace) the temp sender first. See how that goes and get back to us. _________________ 1986 Westy 2WD auto a.k.a. "The Old Girl"
www.kittenfart.com |
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tencentlife Samba Member
Joined: May 02, 2006 Posts: 10067 Location: Abiquiu, NM, USA
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Posted: Wed Aug 27, 2008 2:10 pm Post subject: |
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Could be a bad level sensor in the pressure tank, or it could be a bad pressure cap, or it could be you haven't kept your reserve tank filled and are losing a bit of coolant somewhere.
When the engine is cold, the coolant contracts like anything made of matter does. As pressure within the system falls below atmosphere, the pressure cap allows some coolant to flow in from the reserve if the difference is more than about 1psi. If that aspect of the cap isn't working, or your reserve is empty, the level sensor could be high and dry at startup and signals a low coolant warning. On the early cars that meant the light would blink AND the gauge would go high. On later cars they fixed it so only the light blinks, so you can tell the difference in warnings. In your case, obviously if your gauge goes high right after startup it's not because the engine is hot. But as the coolant expands, it may be the level rising immerses the sensor and the light goes out.
So before your next cold-start, take a look at the level in the pressure tank. It should be filled to the top. If it's not, take the cap off and top it off with 50/50. Make sure your reserve always has some coolant in it, too. After topping it off, see if you get the warning again. If not, lack of immersion of the level probes was the problem that gave the warning, but it also means that you're losing some coolant somewhere. A thorough visual check or a pressure test would be the next steps.
The sensor probes can also get cruddy and merely taking it out and wiping them clean restores function. And of course, they do go bad.
There's a thread in the stickys about diagnosing the level sensor circuit. _________________ Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/
Please don't PM here, I will not reply.
Experience is kryptonite to doctrine. |
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