2000 4.2 Overheating at Idle -- Fan Problem?
07-06-2010, 06:29 PM
#12
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07-06-2010, 06:57 PM
#14
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07-06-2010, 09:02 PM
#15
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Thanks, Joe! But isn't that the part number for the A/C condenser fan, i.e. the fan on the front of the radiator? I'm thinking that the part number for the aux fan I need is probably either
8D0 959 455P
8D0 959 455R or
VW3115105.
What would a coolant flush accomplish, given that the coolant is supposed to be good (can provide proper anti-boil, anti-freeze, and corrosion protection) for the lifetime of the car? I should point out as well that the coolant bottle fractured 5 years back or so, at which point I'm pretty sure most if not all the coolant was replaced.
8D0 959 455P
8D0 959 455R or
VW3115105.
What would a coolant flush accomplish, given that the coolant is supposed to be good (can provide proper anti-boil, anti-freeze, and corrosion protection) for the lifetime of the car? I should point out as well that the coolant bottle fractured 5 years back or so, at which point I'm pretty sure most if not all the coolant was replaced.
You might be right with the part number, I have a old scan from a parts book and that is the only fan loaded.
07-07-2010, 08:40 AM
#17
AudiWorld Member
Thread Starter
Agreed. The Audi part number for a 1.5 litre bottle of the pink stuff is ZVW 237 G12. It's Pentosin Lifetime Antifreeze G001200. It should be mixed 1:1 with water (preferably distilled or otherwise filtered) for greatest protection against freezing and overheating. Available at many European car dealers (VW, Audi, BMW, MB, Jag, etc.) or from any number of parts places on the web (ECS Tuning, Blauparts, German Auto Parts, Amazon, etc.).
07-07-2010, 09:59 AM
#18
AudiWorld Member
Thread Starter
A couple updates for the benefit of the collective wisdom:
I discovered that both the A/C fan in front of the radiator and the aux fan behind the radiator are VERY easily removed. To get the aux fan out, you remove one screw and then twist the whole assembly and lift it out. To get the A/C fan out, you remove two Torx screws plus one bolt at the bottom (accessible through the grille below the bumper), slide the fan to the center of the car (where there's slightly more room between the bumper and the A/C condenser and radiator) and then lift the whole assembly out. Took less than 5 minutes to get each fan out having no idea what I was doing when I started.
I also discovered that it's possible to cross plug the fans into each other's spot on the wiring harness under the black plastic shield next to the power steering pump (the aux fan has black connectors, and the A/C fan has brown connectors). The plugs are designed with some minor differences in the way the plastic is formed to make them more idiot proof, but they'll mate with each other if you use some minor creative persuasion on the plugs. Both harnesses output approximately 11 volts.
I am PRETTY sure the motors on both fans are the same, but that the blades and the mounting arms on each fan support are slightly different. I don't plan to switch the blades to find out. For those who may want to undertake such an adventure, be advised that the blades are attached with reverse-threaded nuts. I think the difference in blades is what accounts for the howling noise the A/C fan makes when running.
The bottom line is that my aux fan does not work consistently when plugged into either harness, whereas my A/C fan works 100% when plugged into either harness. So my presumption at this point is that my aux fan is bad and not the controller or wiring, etc.
My bad aux fan with part number 4B3 959 455 is identical to part 8D0 959 455 that my local VW dealership carries (for $400). However, the part the VW dealer stocks is available from RockAuto.com as 8D0 959 455R (note the R on the end) for $75, so I'll be ordering it from there. See http://www.rockauto.com/catalog/moreinfo.php?pk=952469 for more info. You can also order it from ECS Tuning for something like $110, plus there are a couple fans on eBay for $65 if you want to fiddle around with that route.
I discovered that both the A/C fan in front of the radiator and the aux fan behind the radiator are VERY easily removed. To get the aux fan out, you remove one screw and then twist the whole assembly and lift it out. To get the A/C fan out, you remove two Torx screws plus one bolt at the bottom (accessible through the grille below the bumper), slide the fan to the center of the car (where there's slightly more room between the bumper and the A/C condenser and radiator) and then lift the whole assembly out. Took less than 5 minutes to get each fan out having no idea what I was doing when I started.
I also discovered that it's possible to cross plug the fans into each other's spot on the wiring harness under the black plastic shield next to the power steering pump (the aux fan has black connectors, and the A/C fan has brown connectors). The plugs are designed with some minor differences in the way the plastic is formed to make them more idiot proof, but they'll mate with each other if you use some minor creative persuasion on the plugs. Both harnesses output approximately 11 volts.
I am PRETTY sure the motors on both fans are the same, but that the blades and the mounting arms on each fan support are slightly different. I don't plan to switch the blades to find out. For those who may want to undertake such an adventure, be advised that the blades are attached with reverse-threaded nuts. I think the difference in blades is what accounts for the howling noise the A/C fan makes when running.
The bottom line is that my aux fan does not work consistently when plugged into either harness, whereas my A/C fan works 100% when plugged into either harness. So my presumption at this point is that my aux fan is bad and not the controller or wiring, etc.
My bad aux fan with part number 4B3 959 455 is identical to part 8D0 959 455 that my local VW dealership carries (for $400). However, the part the VW dealer stocks is available from RockAuto.com as 8D0 959 455R (note the R on the end) for $75, so I'll be ordering it from there. See http://www.rockauto.com/catalog/moreinfo.php?pk=952469 for more info. You can also order it from ECS Tuning for something like $110, plus there are a couple fans on eBay for $65 if you want to fiddle around with that route.
Last edited by spoon2000; 07-07-2010 at 12:47 PM.
07-07-2010, 10:50 AM
#19
AudiWorld Senior Member
This is great info! I think my A6 has the same problem. It has gotten pretty warm at idle. I've personally witnessed 5 or 6 VW cooling fans fail, so I suspect the construction and reliability of these is probably similar. Going to dig into them this evening.