HOWTO -- Thermostat replacement on B6 A4 1.8T - w/pics

Matt Devo · 06-12-2006, 09:01 PM

I used the writeup by Mark955 on AW, but thought I'd add some pics for the more visually-oriented =). All pics can be clicked for larger versions.

Thermostat is part # 06B-121-111-G. my original was a -D, and I believe G is being replaced by H (as per my invoice).

the operating area:

Step 1: Drain coolant (sorry no pics)

Remove bottom belly pan. Remove coolant reservior tank cap. Remove plastic clip holding coolant sensor in place at lower radiator hose/pipe. With bucket/catch pan underneath, remove sensor and let coolant drain.

Step 2: Remove upper radiator hose

remove the small hose connecting the coolant reservior to the upper radiator hose. Then remove the larger hose from the hard pipe running along the intake and from the radiator. You'll need to pop up (but not off) the metal clip holding the hose to the radiator, then firmly pull back:

hose removed:

Step 3: Remove intake hose (throttle body-to-intercooler)

remove driver's side headlight (not necessary but makes it a lot easier). Loosen clamp at each end and remove hose.

Step 4: Remove throttle body

remove electrical connector and 4 hex bolts (5mm):

removed:

Step 5: Loosen serpentine belt and slip off of alternator

use a box-end or adjustable wrench on tensioner, pull to the right. Carefully slip belt off alternator (towards front of car). Allow to hang loose below

Step 6: Remove alternator bolts

remove 4 bolts holding alternator to bracket:

Step 7: Remove electrical connector and grounding cable from alternator

after removing the 4 bolts, lay the alternator face down on the top of the fan and remove the electrical connector, and the grounding strap. If you haven't disconnected the battery, be sure to cover the grounding strap in tape so it cannot touch other metal surfaces

alternator removed; grounding strap shown:

Step 8: Remove vertical support piece from intake manifold to block

remove the two bolts holding the support piece (6mm hex):

Step 9: Remove bolt from metal hose on t-stat; remove bolt from top of oil cooler

this will allow you to move the hard pipe away from t-stat. On my car, even after removing the bolt I was unable to remove the hard pipe at this time - I had to remove the thermostat from the block, then wiggle it free from the pipe afterwards

bolt holding the hard pipe on the right, two bolts holding the t-stat to the block on the left:

bolt holding the metal pipe to the top of the oil cooler (as seen from top of intake):

Step 10: Remove upper and lower hoses fom t-stat. Remove electrical connector on back side

Step 11: Remove 2 bolts holding t-stat to block, and remove t-stat

(I'm reusing a pic, please don't sue me)

Step 12: Install new thermostat

install new thermostat, making sure to remove the old O-ring. The new t-stat will include a new one. I wet my finger with coolant and ran it along the O-ring to pre-lube it before installation. Otherwise, install is reverse of removal:

All done - looks just like when we started!

Disclaimer: this information is for educational purposes only. Poster is not responsible if you somehow manage to blow up your car in the process.

bhvrdr · 06-13-2006, 04:06 AM

Eddie Man · 06-13-2006, 04:18 AM

time to such a detailed write-up...
Kudos to you for a great job.
Thanks for sharing

Matt Devo · 06-13-2006, 06:08 AM

forced induxion · 06-13-2006, 07:07 AM

a4tis™[Bye Turbo] · 06-13-2006, 07:16 AM

bhvrdr · 06-13-2006, 09:17 AM

06-13-2006, 04:06 AM	#2
bhvrdr Member Garage is empty, add now Join Date: Jun 2003 Posts: 13,772	Did your problems go away Matt? __________________ Cheers! Mike ________________________________________ A4 S4 and RS4 Official Timeslip Databases MJB Motorsport Click for S4 at Play VIDEO!!! ________________________________________ Current vehicle: 2004 Audi S4, APR, Milltek, Bilstein, AP Racing. Over 323whp and 312tq on pump 93 13.20 at 103mph on pump 93 Past Project Vehicles: 2006 Audi A4 2.0t FSI with APR K04 Turbo 2003 Audi A4 1.8t with MTM Stage 3 2000 Audi A4 1.8t with MTM Stage 2 "There are only three sports: bullfighting, mountain climbing, and auto-racing. Everything else is just a game" -Ernest Hemingway

06-13-2006, 04:18 AM	#3
Eddie Man AudiWorld Super User Garage is empty, add now Join Date: Sep 2000 Posts: 6,562	What an awesome write-up! I love it when one can crack the screws, scrap the knuckles and have... time to such a detailed write-up... Kudos to you for a great job. Thanks for sharing __________________ 2006 S4 Avant dolphin gray \| 6speed \| alcantara \| premium \| cold \| bose \| sirius \| navigation \| bluetooth \| parktronic \| ebony \| carbon fiber *GOT MODS? >>> http://www.audizine.com/forum/showth...60175-Got-Mods*

06-13-2006, 06:08 AM	#4
Matt Devo AudiWorld Super User Garage is empty, add now Join Date: Mar 2003 Posts: 6,874	yes sir, thanks for pointing out the problem __________________ ------------- 2002 A4 1.8T 5M. 130k miles and counting AIM/Gamertag: denimA4turbo

06-13-2006, 07:07 AM	#5
forced induxion AudiWorld Super User Garage is empty, add now Join Date: Oct 2005 Posts: 2,065	perfect...i'm going to use this next weekend. __________________ -----------------------------------------------------------

06-13-2006, 07:16 AM	#6
a4tis™[Bye Turbo] Senior Member Garage is empty, add now Join Date: Aug 2005 Posts: 5,662	excellent write-up, i'm def saving this one __________________ 2000 S4 6-spd (MTM Stg I) MTM ECU APR Bipipe 710Ns RS4 MM APR Snub ASP DTS Stasis Street Sports 'Darintake' Airbox Mod VAST short shifter Clear Corner Mod How to fix your randomly opening sunroof THE B5 S4 FAQ How to install a boost gauge

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06-13-2006, 09:17 AM	#7
bhvrdr Member Garage is empty, add now Join Date: Jun 2003 Posts: 13,772	Awesome. Good to hear bud. __________________ Cheers! Mike ________________________________________ A4 S4 and RS4 Official Timeslip Databases MJB Motorsport Click for S4 at Play VIDEO!!! ________________________________________ Current vehicle: 2004 Audi S4, APR, Milltek, Bilstein, AP Racing. Over 323whp and 312tq on pump 93 13.20 at 103mph on pump 93 Past Project Vehicles: 2006 Audi A4 2.0t FSI with APR K04 Turbo 2003 Audi A4 1.8t with MTM Stage 3 2000 Audi A4 1.8t with MTM Stage 2 "There are only three sports: bullfighting, mountain climbing, and auto-racing. Everything else is just a game" -Ernest Hemingway

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