[V6-12v] Thermostat lifespan

[Tom Christiansen]

Austin (et. al):

The old thermostat (BBT brand) was broken in two. The new thermostat
($30 at the stealership) Wahler brand fixed the problem.


Tom

On 7/5/06, Austin Franklin <austin.franklin at charter.net> wrote:
> Hi Tom,
>
> But...did replacing the thermostat solve the problem?
>
> Regards,
>
> Austin
>
> > -----Original Message-----
> > From: v6-12v-bounces at audifans.com [mailto:v6-12v-bounces at audifans.com]On
> > Behalf Of Tom Christiansen
> > Sent: Wednesday, July 05, 2006 12:42 PM
> > To: v6-12v at audifans.com
> > Subject: Re: [V6-12v] Thermostat lifespan
> >
> >
> > Folks,
> >
> > Quick recap: It took for ever for the engine in my 1994 90S to warm up
> > and I had no heat at the vents. Only in stop & go traffic would the
> > engine warm up (in 60-70 deg F (15-20 C) weather).
> >
> > I shook the expansion tank cap and it did not rattle. This can be a
> > sign of a stuck valve, which, according to several list members can
> > cause the system to show the symptoms I describe. A new cap was about
> > $6.50 at the dealer so it was worth a try. Unfortunately, it did not
> > fix the problem.
> >
> > So I replaced the thermostat, which on the AAH/AFC engines can be done
> > without removing the timing belt. Here's how I did it:
> >
> > 1) Remove belly pan, top engine cover. Drain coolant and dispose
> > of it properly.
> > 2) Remove radiator fans to give you more room.
> > 3) Remove front plastic cover on engine.
> > 4) Remove accessory belt and tensioner.
> > 5) Remove timing belt covers. Be careful as the plastic can be
> > rather brittle.
> > 6) Remove the coolant hose at the thermostat housing.
> > 7) Remove two 10 mm bolts that hold the housing. One is above the
> > idler/roller for the timing belt, the other is under the large pulley
> > at the top (use a 1/4" drive socket, universal joint, and a short
> > extension).
> > 8) Wiggle the thermostat housing out from underneath the timing belt.
> > 9) Replace thermostat and the O-ring around it.
> > 10) Assembly is reverse of removal.
> >
> > Remember to bleed the system when you fill it with coolant. Getting
> > the thermostat housing out is a real chore as the thermostat gets
> > caught on it. But it is possible to get it out (the Bentley Manual
> > even says so). It took me around 15 minutes to get it out. 10-15
> > minutes to get it back in. The whole procedure took 1.5 hours. Add 30
> > minutes for bleeding the system (waiting for the engine to heat up)
> > and tool clean-up.I took the time to make sure the timing belt was
> > clean and I rotated the engine a couple of revs by hand before putting
> > the covers on. Just as a precaution.
> >
> > Relevant torques:
> > Thermostat housing bolts: 10 Nm
> > Accessory belt bolt: 55 Nm
> > Bleed screw in the hard coolant line by the EGR valve: 15 Nm
> >
> >
> > Tom
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