[V6-12v] Radiator Fans not switching in correctly...

[James Whitehouse]

Marc,

It's a valid question, but I don't know what sensor reads the outside temp -
which one are you thinking of, and how would I check whether it's accurate?

Thanks for the zinc paste info!

Cheers,
James

> -----Original Message-----
> From: The CyberPoet [mailto:thecyberpoet at cyberpoet.net]
> Sent: 29 August 2006 20:42
> To: James Whitehouse
> Subject: Re: [V6-12v] Radiator Fans not switching in correctly...
> 
> here's some more info on those zinc-suspension pastes:
> http://sw-em.com/anti_corrosive_paste.htm
> 
> Q: are you getting a valid reading from the outside temp sensor? If
> it's reading way too low or not at all, it might affect the system
> logic for the fans...
> 
> Cheers
> =-= Marc
> 
> On Aug 29, 2006, at 1:13 PM, James Whitehouse wrote:
> 
> > Marc,
> >
> > Thanks for that, I'll try cleaning the connector on the radiator-
> > mounted
> > thermo switch first. I don't have any knowledge of anything similar to
> > 'Nolox', but I use DeoxIt as a contact cleaner often and it seems
> > to work
> > OK. If that doesn't help, I'll probably try replacing that thermo-
> > switch
> > first, followed by the 'radiator fan 1st speed' relay in the fuse
> > box -
> > they're not expensive parts.
> >
> > If anyone else has any more info/ specs on the system, please let
> > me know,
> > I'd be grateful for any fault finding procedures, etc.
> >
> > Cheers,
> > James
> >
> >
> >> -----Original Message-----
> >> From: The CyberPoet [mailto:thecyberpoet at cyberpoet.net]
> >> Sent: 28 August 2006 12:22
> >> To: James Whitehouse
> >> Cc: v6-12v at audifans.com
> >> Subject: Re: [V6-12v] Radiator Fans not switching in correctly...
> >>
> >> This isn't my area of expertise, but I do know that on my V6's (at
> >> least based on my experiences), the following seems generally true:
> >>
> >> (A) There are two electrically-driven fans, the primary one triggers
> >> on temp of the radiator temp sensor, and the second of which triggers
> >> based on air conditioning use (as well as kicking on at a higher
> >> thermal level threshold for the radiator/engine).
> >>
> >> (B) The wiring connectors for the sensors is often the first thing to
> >> go bad, because of exposure in my experience. Cleaning the contacts
> >> thoroughly & dielectric grease is often the best place to start.
> >> Sidenote: I've found a dielectric grease called Nolox that contains
> >> zinc particles in the suspension which forces a fresh cut through
> >> surface corrosion on connectors every time the plugs are mated works
> >> better than traditional vasoline-like dielectric grease if there is
> >> already a problem with connectivity. There are Brit-market
> >> equivalents (I selected Nolox because all the other options were UK-
> >> based and not readily available here). This is not a total solution
> >> for bad connectivity, but given a connector that already had to be
> >> cleaned of surface corrosion once, I'll grab the nolox just to
> >> improve the situation in the future (such as plugging/unplugging tail
> >> light connectors on the road where I don't carry a full toolkit with
> >> sandpaper, etc. with me)...
> >>
> >> Now, having said that, are you SURE the radiator is getting the hot
> >> fluids in volume? A partially-blocked or slow-opening/inop thermostat
> >> valve at the block might be preventing the radiator from getting the
> >> hot fluids in volume, and thus the sensors for the radiator aren't
> >> reading it as too hot (just a thought). Taking a kitchen probe or
> >> laser/infra-red temp probe to the radiator and hoses should tell you
> >> definitively (a hand would probably tell you too, but I won't suggest
> >> you potentially burn yourself to find out).
> >>
> >> Good Luck!
> >> =-= Marc Glasgow
> >>
> >> On Aug 28, 2006, at 6:36 AM, James Whitehouse wrote:
> >>>
> >>> - Engine waits until it's one mark beyond the 'normal' temp mark
> >>> (the more
> >>> distinctive 'centre' thicker splodge of white mark on the dash),
> >>> then both
> >>> fans kick in (full speed?) for about 20 seconds. They then turn off
> >>> again
> >>> without having cooled the engine.
> >>>
> >>> I'm guessing that a) first speed fans aren't working, as I remember
> >>> them
> >>> kicking in before that mark, and staying on longer, then 'speed 2'
> >>> kicking
> >>> in when sitting in traffic for ages, bringing it down to 'speed 1'
> >>> temp.
> >>>
> >>> If anyone has info, or fault finding for this system, could you let
> >>> me know
> >>> please?
> >>>
> >>> TIA
> >>>
> >>> James
> >>
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> >>
> >
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> >
> >
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