2000 4.2 Overheating at Idle -- Fan Problem?
#22
AudiWorld Member
Thread Starter
Both my factory fans and the fan at the VW dealership were made by Gate is that's of any value. The one I ordered from RockAuto is a no-name, whatever's on the shelf brand; for a 10 year old car, I don't really care, especially since I now know how to diagnose and remove/reinstall and know that a replacement is only $80 shipped.
#23
AudiWorld Member
Thread Starter
For what it's worth, RockAuto has already shipped my new fan, so I'm hoping it will be here tomorrow.
#25
AudiWorld Member
Thread Starter
When I first called the Audi dealer this morning to ask what the part number was for the aux fan, I was given the wrong part number (the one for the A/C fan), and only when I called back did the parts guy tell me "Oh yeah, there's another fan listed there, too -- 8D0 959 455L." So you have to be careful about what part numbers are being listed for what application. Some parts breakdowns I've seen for the 4.2 don't even list an aux fan, and some listings for the 8D0 959 455 part number indicate that it's only applicable to the 4.2 starting in MY 2002, so some detective work is required. I'm praying that whatever FedEx brings tomorrow will be a direct fit, or at a minimum, that I'll be able to swap the motor and blade into the old fan mounting and attach the whole business to the radiator.
The 8D0 959 455 part number (which the Audi dealer gave me, and which was on the fan identical to my dead fan that I saw at my VW dealer down the street from me) is what I cross-referenced to place my order from RockAuto.
When I was at the VW dealer, I picked up a gallon jug of VW/Audi pink coolant -- part G-012-A8G-1G for $22. Considering that pink Pentosin runs about $10 plus shipping for 1.5 quarts, that seemed like a good deal, and it made me feel a bit less guilty about having made the parts guy drag out an aux fan from the warehouse so I could compare it to my dead one.
Last edited by spoon2000; 07-08-2010 at 06:09 PM.
#26
AudiWorld Member
Thread Starter
OK, so here's the deal... The fan arrived. It's made by Tong Yang Group of Taiwan. Seems well enough built, and the box says it's made for '01-'05 VW Passat and Audi A8/S8. Unfortunately, it's not an exact duplicate of the OEM version that I removed from the car -- it's about 1 inch thicker from front to back. Part of the extra thickness is in the blade, and part is in the motor, which looks beefier than the OEM fan motor (fine by me!). In any case, I got it installed by removing the cover from the timing belt to make a bit more space, disassembling the fan motor and blade from the support structure, and then first dropping the motor and blade into place and then dropping the support structure into place and bolting things together. Even then, the motor housing was extremely close to the exposed drive belt pulley, so I added some spacers (extra nuts) to the mounting bolts so the fan would sit a bit (like a quarter inch) farther forward inside the radiator and away from the engine. Seems to work fine. Pictures of everything to follow.
The bad news is that after replacing the fan, the car still has an overheating problem. As soon as the engine got up to operating temperature, the needle started to rise, and then the dreaded red thermometer with the obnoxious dancing waves appeared in the middle of the dash. I got out and popped the hood, and found that all three fans were spinning away full blast.
So... I think I'll replace the thermostat (which went bad once before a couple years back and caused overheating), and then if that doesn't work, I'll take the beast to my local shop for what I can only assume will be a water pump and timing belt replacement (the car has 85K miles and I don't think the water pump and timing belt have ever been changed out).
Any other thoughts or good karma?
The bad news is that after replacing the fan, the car still has an overheating problem. As soon as the engine got up to operating temperature, the needle started to rise, and then the dreaded red thermometer with the obnoxious dancing waves appeared in the middle of the dash. I got out and popped the hood, and found that all three fans were spinning away full blast.
So... I think I'll replace the thermostat (which went bad once before a couple years back and caused overheating), and then if that doesn't work, I'll take the beast to my local shop for what I can only assume will be a water pump and timing belt replacement (the car has 85K miles and I don't think the water pump and timing belt have ever been changed out).
Any other thoughts or good karma?
#28
AudiWorld Member
Thread Starter
Any way to tell if the water pump is dead in the absence of leaking coolant? And any way to tell in advance about the thermostat (I hear the old feeling the hoses trick isn't so reliable, because if the lower hose is cool, it can be from a stuck thermostat or from a radiator that's actually doing a really good job)?
#29
AudiWorld Member
Thread Starter
Ugh. Looked at Bentley manual, decided pretty quickly to make an appointment with the mechanic. Timing belt has to come off, etc. And it may not even be the thermostat that's gone off the rails; better to let the shop decide at this point what's causing the ongoing overheating. MANY thanks to all for the assistance thus far.
#30
Ugh. Looked at Bentley manual, decided pretty quickly to make an appointment with the mechanic. Timing belt has to come off, etc. And it may not even be the thermostat that's gone off the rails; better to let the shop decide at this point what's causing the ongoing overheating. MANY thanks to all for the assistance thus far.
The jobs is just time consuming and if you have a Bentley you can DIY it. From the sounds of it you are very mechanically inclined. Give it a go because at 85k miles you do need to do a timing belt, water pump and thermostat regardless.
Our Timing Belt kits start at about 420 and work their way up. They include everything, including seals that are commonly known to leak. Imagine what a shop would charge to replace all this for you! Click here for timing belt kits. You are so close, don't give up!
(Also that hose trick is a pretty good one in a pinch)
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