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    VWVortex


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    Thread: VR6 Cooling system repair

    1. Member
      Join Date
      Dec 30th, 2005
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      177
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      2002 Jetta VR6 5-spd
      01-05-2012 09:15 PM #1
      2002 Jetta GLX Wagon 12V VR6 5-speed 152K miles

      We've owned it since brand new in Aug 2002. For the last year or so its been 'losing' a bit of coolant over time. It had gotten pretty bad the last month or two as I had to check it every night and I was adding about 2 lites of 50/50 per week. In early November I finally got under the car to see if I could see where it was leaking from. It was easier to see where it wasnt. Basically I could see that it was leaking from the bottom of the radiator and from somewhere around the thermostat housing. I decided to replace the radiator, thermostat housing, thermostat, and thermostat elbow as well as all o-ring seals/gaskets used at these components. I also noted that there are several steel coolant 'pipes' (or tubes) that were very rusty on the outside and I decided to replace those as well. I re-used most hoses as they were OK. I used genuine VW parts and ordered everything I needed from 1stVWparts. They were very helpful in helping me figure out the parts I needed. I had done some work on this car in the past (brakes, coilpack, PS pump, etc) but never had worked on the cooling system. I didnt even have a repair manual, just what I could find online (mostly here at the Vortex). This is not intended to be a complete DIY but I hope this is a helpful guide to others.


      First thing is to get the car securely on jackstands and disconnect the battery


      Disconnect the external hood latch release and remove the grille


      Remove the bumper cover. You need to remove the front marker lights housings. Be VERY careful, I broke one when I disconnected the bulb socket from the housing as the plastic gets very brittle over time (in the end this was the only casualty). You dont need to remove the tires to get to the fasteners in the wheel wells just turn the wheels full left to do the right side and vice versa. Also remove the drivers side lower splash shield (not shown). Its held with one screw and two 'reverse starfish' type spring clips that you pry down off their retaining studs.



      Remove the styrofoam bumper cushion from the bumper (it pulls straight off), the headlight assemblies, and bumper from the radiator support. Ive seen DIYs where the bumper is not removed but it makes handing the radiator support/radiator much easier as its much lighter without the bumper. Also remove the end of the hood release cable from the hood latch




      Disconnect the two fan connectors and the fan switch connector on the radiator (shown
      still connected)


      Drain the radiator into suitable containers. We were adding so much coolant the last few months that everything that came out was clean and able to be reused. About 1-1/3 gallons came out
      Last edited by mwr02jetta; 01-06-2012 at 01:52 PM.

    2. Member
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      2002 Jetta VR6 5-spd
      01-05-2012 09:37 PM #2
      When the coolant stops draining remove the lower radiator hose. I disconnected the hose from the radiator connector at this time. Be prepared for some more coolant to spill/splash from the hose. From this angle you can kind of see where the radiator was leaking


      Remove the upper radiator hose. Again I disconnected the hose from the radiator connector for now


      Remove the two bolts that hold the radiator support to the fenders and lower the entire radiator support/radiator/AC condenser/electric fan assembly onto a suitable support (I used a wide milk crate). Its at this point that you will be glad you removed the bumper. Even without the bumper this weighs quite a bit



      Remove the fan assembly from the radiator


      With the fans removed you can really see how bad this radiator was


      Finally remove the radiator support from the radiator/AC condenser assembly and remove the radiator. All that will be left is the AC condenser still connected to the rest of the AC plumbing. No need to disconnect it but you want to support it


      Now I could really see that this radiator was a mess. I transfered the hose connectors, fan switch, and radiator mounts to my new radiator
      Last edited by mwr02jetta; 01-06-2012 at 01:43 PM.

    3. Member
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      2002 Jetta VR6 5-spd
      01-05-2012 09:52 PM #3
      Getting to the thermostat housing is a real PITA. Start by removing the coil pack. Im an expert at this since Ive replaced 4! of them in this car's 152K mile life. You could just disconnect the spark plug wires at the coil but I pulled the wires back too so that I could remove the plastic engine cover. No need to disconnect the spark plug wires from the spark plugs. Also I disconnected the ribbed air hose and the small water hose that are just above the coilpack


      There is a wire harness bracket that mounts to the thermostat housing mounting screws. Disconnect the wire harness from the bracket. Disconnect the hose that comes from the rear to the thermostat housing and them remove the three screws that mount the thermostat housing to the engine





      Disconnect the hoses from the drivers side of the upper and lower crossover pipes


      Finally remove the three bolts that hold the thermostat housing to the engine and remove the housing. As you can see I removed the housing with many hoses still attached to it as I think this is the easiest way since I will be re-using the hoses and transfering them to the new housing. Im sure there are other ways to do it. I had a bit of a time getting the housing to break loose from the end of the coolant (aka 'crack') pipe. Once out the housing and hoses looked like this


      At this point I was about 3 hours into the job
      Last edited by mwr02jetta; 01-06-2012 at 01:46 PM.

    4. Member
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      2002 Jetta VR6 5-spd
      01-05-2012 11:01 PM #4
      A quick look at the thermostat housing sealing surface and seal verified what I had suspected - that the housing was leaking where it attached to the engine. If you look closely you can see where a piece of the inner wall of the seal retaining groove has eroded away.


      This is the surface of the engine where the thermostat housing attaches. Ugh, what a mess! No turning back now.



      Here a good pic of the end of the coolant (aka 'crack') pipe that goes into the thermostat housing. The o-ring seal looks OK but it will be replaced


      Stuffed some towel paper in the coolant port and went to work on that sealing surface with a fresh razor blade in a holder. For the new housing to seal this surface needs to be CLEAN and SMOOTH



      The only thing on the old thermostat housing thats being kept is the ECT sensor and the sensor port plug. The housing, elbow, thermostat, and all seals/retainers are new. I even used new stainless steel cap screws for mounting the elbow. You can see the old and new parts here









      I transfered the old hoses to the new housing. You want to keep track of what hoses go where. I transfered them one at a time to be certain. I didnt install the seal in its groove until I was ready to install the housing
      Last edited by mwr02jetta; 01-06-2012 at 01:48 PM.

    5. Member
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      2002 Jetta VR6 5-spd
      01-05-2012 11:25 PM #5
      Before I replaced the thermostat housing I replaced the three coolant pipes/tubes that were very rusty. There is an upper crossover pipe, a lower crossover pipe and one L shaped pipe that mounts on the passenger side near the auxiliary radiator


      I was able to remove the L shaped and lower pipe together




      Transfered the hoses to the new pipes and re-installed. The L shaped pipe has a bracket welded to it that supports an AC line clamp. The clamp screw on mine was rusted and almost didnt come off. I replaced it with a shiny new stainless screw.







      The upper crossover pipe is held to the upper intake manifold with two bolts that hold the upper manifold. The one on the passenger side needs to be removed with a L wrench because its directly lined up with a part of the AC plumbing so you cant get to it with a socket bit



      Last edited by mwr02jetta; 01-09-2012 at 08:25 PM.

    6. Member
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      2002 Jetta VR6 5-spd
      01-05-2012 11:47 PM #6
      Time to install the thermostat housing. The molded o-ring is installed in the groove in the housing. It has little retaining tabs molded into it



      I replaced the o-ring on the end of the crack pipe and lubed it with coolant. The housing is snaked into position and reinstalled with the three mounting screws. Dont forget to re-install the harness retaining bracket (ask me how I know)






      I re-installed the coilpack, engine cover, and spark plug wires


      The radiator is new but I needed to transfer the hose connectors,fan switch, and mounts over. I installed new o-ring seals in each connector and a new gasket under the fan switch. Interestingly the fan switch did not have a gasket under it from the factory. Local dealer parts guy told be there should be one so I purchased and installed it.

      New VW radiator


      Connectors and fan switch removed from old radiator


      New o-rings and sealing washer



      New radiator assembled and ready to install



      Old and new
      Last edited by mwr02jetta; 01-06-2012 at 01:56 PM.

    7. Member
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      2002 Jetta VR6 5-spd
      01-06-2012 12:06 AM #7
      Start the final assembly by placing the new radiator on top of the AC condensor


      I then installed the fans on the Radiator/condenser assmbly and bungied that to the engine thinking that I would be able to install the radiator support to it from the front


      But that didnt work to well as it was difficult to get the four radiator mounts to line up with the receptacles in the radiator support. In the end I removed the bungies and laid the radiator flat on top of the radiator support and got everything lined up. Another thing I would do differently is I would not install the fans until the radiator/condenser was installed in the support as the weight of the fans makes everything more difficult when your trying to line up the mounts



      Finally raise up the radiator support/radiator/condenser and line up the support to the front fenders and install the bolts at each end. Re-connect the upper and lower radiator hoses, fan connectors, and fan switch. Re-install the bumper. Can you see our new radiator?


      At this point before installing the headlights and bumper cover I re-filled the system thru the reservoir until it wouldnt take anymore which was all but about half a gallon of what drained. I bumped the engine over without starting and the level dropped and I was able to add a bit more. I then started the engine. Strange but it would not start initially and I thought I left something disconnected but I got it started (held the pedal to the floor) and I think it was just from having the battery disconnected for a while and the PCM memory lost. I let it warm up and kept adding coolant to the reservoir as the air was purged and the level dropped until it didnt drop any more. So far no leaks and all is well.

      I hope this has been helpful.
      Last edited by mwr02jetta; 01-06-2012 at 08:05 AM.

    8. Member crrdslcvr6's Avatar
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      May 3rd, 2006
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      1993 Corrado, 2001 330Ci
      01-06-2012 02:10 AM #8
      Good job!

    9. Junior Member k2snowboarder1031's Avatar
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      2000 GTI VR6
      08-22-2012 12:31 PM #9
      where did you get the new metal coolant lines from?

    10. Member dogyouare's Avatar
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      90 Jetta GL, 91 Corrado G60, 96 Golf GTI, 88 300SE
      08-22-2012 01:33 PM #10
      Quote Originally Posted by k2snowboarder1031 View Post
      where did you get the new metal coolant lines from?
      those tag on them means it came from dealer.

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