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RIP
RIP, Lead Technician
Category: VW
Satisfied Customers: 5591
Experience:  VW Factory training, ASE Master Technician, Adv. Engine Performance 10 years
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How do I change the Thermostat on a 1999 Passat

This answer was rated:

It is a v6

Hi, welcome to Just Answers,

I'm posting the procedure below to replace the t-stat...typically the thermostat is replaced when the timming belt and waterpump are serviced.

Service and Repair
Notes

Thermostat, removing and installing

Special tools and equipment

graphic

  • VAS 5024 Assembly tool for spring-type clips
  • VAG 1306 Drip tray
  • VAG 1331 Torque wrench (5-50 Nm)

Note: Always replace seals and gaskets.
Cover toothed belt with a cloth to protect it from coolant before removing thermostat.

Removing

graphic

  • Unscrew connection securing bolt -1 and remove connection -2-.
  • Take out thermostat -4-.

Installing

Installation is carried out in the reverse order, when doing this note the following:

  • Moisten new O ring -3- with coolant.
  • Fit thermostat -4- into engine block.

graphic

Note: The thermostat bleeder valve (arrow) must be on top

graphic

  • Tighten securing bolt -1-.
  • Tightening torque: 10 Nm

Installing toothed belt and adjusting timing, refer to Engine - Timing Components - Timing Belt - Service and Repair - Procedures See: Engine\Timing Belt\Service and Repair

 

 

The hyperlinks are disabled...if you need any further information, just let me know :)

 

Customer: replied 8 years ago.
I believe you are very helpful and I will ACCEPT
as soon as I can get on to ALLDATA and look at the proceedures that are linked. I cannot open any proceedure unless I have a username and password. Does this cost more???

As I mentioned at the bottom of the post the hyperlinks are disables, this is information from our shop Alldatapro that can be uploaded here but not accessed. If you need further information, on any portion let me know; most of the hyperlinks are basic definitions of the component, and some are procedures for related areas.

Rip

Customer: replied 8 years ago.
I wanted to look at the proceedure to loosen the tensioner and remove the ribbed belt. Never had to do that just to change a Tstat before.....

Replacing this thermostat is a very detailed job and you shouldn't attempt it if you've never serviced a engine timming belt on an interference motor. If you get this wrong you can damage the valves in the engine heads. Below is the procdure used to get to the timming belt off after the ribbed drive belt. The front bumper is also removed to start, but it's actually not that difficult, only a couple of bolts hold the entire bumper on since it was designed for this purpose.

Drive belt:

Service and Repair
Notes

Ribbed Belt, Removing And Installing

Special tools, testers, measuring instruments and auxiliary items needed

graphic

  • 3204 Mandrel
  • 3212 Two-hole Pin Wrench
  • 3312 Open-end Spanner
  • VAG 1331 Torque wrench (5 - 50 Nm )

Removing

CAUTION!
Before removing ribbed belt, mark direction of rotation. Belt damage will result if not reinstalled in proper direction.

  • Remove engine cover first.
  • Bring front end assembly (lock carrier) into service position.

graphic

  • Counter-hold viscous coupling pulley with spanner 3212 and remove viscous coupling using wrench 3312 (left-hand thread, -arrow-).
  •  

    graphic

    • Turn tensioning roller clockwise -arrow- with wrench on securing bolt
    • When holes align -arrows-, secure tensioning roller with pin 3204
    • Remove ribbed belt.

    Installing

    • Route ribbed belt to crankshaft pulley/vibration dampener first. Slide belt onto tensioning roller last.

    Remaining installation is in reverse order of removal.

    CAUTION!

    • Viscous coupling must be torqued to 40 Nm (30 ft. lb.) (left-hand thread) using wrench 3312.
    • After installing ribbed belt, check for proper seating and alignment with engine running.

     

     

    Timming Belt:

    Service and Repair
    Notes

    Toothed Belt, Removing, Installing and Tensioning

    Special tools and equipment

    graphic

    • 3242 Clamping bolt
    • 3032 Puller
    • 3391 Camshaft clamp
    • V.A.G 1331 Torque wrench (550 Nm )
    • V.A.G 1332

    Removing

    • Remove ribbed V-belt first.

    graphic

  • Position crankshaft to top dead center No. 3 cylinder. Mark on toothed belt guard -A- must align with notch on belt pulley-B.
  •  

    graphic

    • Check position of camshaft sprockets. Larger holes in securing plate -arrows- must align opposite one another on inside.

    Note: If the larger are positioned to the outside, the crankshaft must be turned one revolution further.

    • Remove sealing plugs from cylinder block, left. Crankshaft TDC drilling must be visible (or be able to be felt) in sealing plug hole.

    graphic

    • Screw clamping bolt 3242 into hole so that crankshaft is secured against turning.
    • Remove tensioner for ribbed V-belt.
    • Remove center and right-hand toothed belt guards.
    • Mark direction of rotation of toothed belt.

    graphic

    • Using 8 mm hex wrench, turn toothed belt tensioner roller-1- counter-clockwise, opposite direction shown (arrow), until tensioning lever-2 compresses tensioner-3- so that spring clamp (2 mm dia.) can be inserted into bore and lifter.

    Note:

    • The toothed belt tensioning element is oil damped and can therefore only be pushed together slowly.
    • The spring pin from 2024 A can be used to secure the tensioning element.
    • Remove crankshaft vibration damper.

    graphic

    • Remove fan retainer and belt pulley toothed belt protection.
    • Take off toothed belt.

    Installing

    • Remove securing bolts for camshaft sprocket and take off securing plate.
    • Fit an M10 bolt into hole as a counter hold for puller 3032.

    graphic

    • Release camshaft sprocket with puller 3032. Then using securing bolts and securing plates tighten hand tight again.

    Note: It must be possible to just turn the camshaft pulleys on the camshaft tapers.

     

    graphic

  • Route toothed belts as shown. Observe direction of rotation for used toothed belts.
  •  

    graphic

    Fit camshaft clamp 3391

    graphic

     

    • Using 8 mm hex wrench, turn toothed belt tensioner roller-1 counter-clockwise, opposite direction shown (arrow), until tensioning lever 2- compresses tensioner -3- so that spring clamp (2 mm dia.) can be removed and then remove clamp.
    • Before starting engine, preload timing tensioner roller as follows:
    • Using a torque wrench with 8 mm hex bit, apply tension to toothed belt clockwise in direction shown (arrow) until a torque of 15 Nm is attained. This ensures tensioner has expanded completely and is properly engaging toothed belt.
    • Tighten camshaft sprocket to 55 Nm after pretensioning toothed belt.
    • Remove clamping bolt 3242.

    The rest of the assembly is basically a reverse of the disassembly sequence.

    RIP and 2 other VW Specialists are ready to help you
    Customer: replied 8 years ago.
    Very detailed answer. Thankyou very much. I will use Just Answers again. You are the best!!

    No problem, let me know if you run into any trouble getting to the t-stat...thanks for the bunus :)

    Rip

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