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Volkswagen Jetta Maintenance and Repair



  • bpeeblesbpeebles Posts: 4,085
    It sounds as if you need to use diagnostic-software
  • ndmike88ndmike88 Posts: 155
    Had the 40k service performed at the dealer today. $586.92 including tax using a 10% off coupon that VW mailed me.
  • This has been driving me crazy for a while now. I've searched all over the web with no luck. My air filter box has 2 big hoses coming off of it. The primary hose goes up to the throttle body as you would expect, but the second one, slightly smaller, goes down to the bottom side of the engine to a small tube that goes into the engine. I've been wanting to take off the old intake tube and box and put a new one on with a cone filter, but I didn't want to do this without knowing what the function of the second hose was, or what it goes to. Does anyone know what this is?
  • bpeeblesbpeebles Posts: 4,085
    It has been awhile since I was under the hood of a '98 2.0L...but here are some thoughts...

    I cannot believe this second hose is connected into the engine-block you surmise, there would be no reason for this.

    I am thinking the second hose you describe is likely a warm-air intake. Does this second hose connect near the firewall around the exhaust? Some cars use this to draw in warm air in cold weather.

    It is also possible this second hose is the PCV breather. (Positive Crankcase Ventilation)...does it connect into the valvecover?

    Finally, are you certain that this second hose is not the INTAKE hose which connects towards the front of the vehicle to draw in cold-air from infront of the radiator? Nearly every fuel-injected car on the road has a cold-air-intake right from the factory. (Waste of $$ to install a CAI kit!!)
  • I have a 1995 jetta my radiator cooling fan will not stop running.In allthe manuals i have read it only discribeshow to test the sensors and switchs if the fan wont run not if it wont stop
  • bpeeblesbpeebles Posts: 4,085
    You did not ask any questions but I will assume you are curious why your radiator fan will not stop running... lets discuss...

    Also, you did not mention if a fan is running when the ignition is turned off... this would help to diagnose the situation.

    You should have two fans.
    1)One of them should run all the time when the AC is engaged. (which includes defrost mode!!)
    2)The other fan should only run when the temperature of the antifreeze gets high enough to turn it on.

    You need to figure out WHICH of the fans is running.... then we can have a further discussion about the possible routes to correct the situation.

    In the meantime, you can test the thermal-switch to see if it is shorted. A shorted thermal-switch is the ONLY way the second fan would run all the time.
  • I have both fan connected by a belt so they both run at same time.they stay on wetherthe ignition is turned off or on. The only way i was able to stop them was to diconnect the battery orunplug cooling fan. Allso whhen this started it was the middle of the night and car hadn't been driven for at least aday. I also tryed unpluging both switchsthat i know are therethatturn the fan on.that didnt stop them kind of stumped i thought if i unpluged switches they should shut off?
  • bpeeblesbpeebles Posts: 4,085
    The two electric fans are connected via belt????? I have been involved with VW since the 1970's and have never seen this kind of set-up.

    In any case, have you tried pulling the fan-relay out.... that should stop the fan from running.

    The VWs I have worked on have no belt between the fans and each fan has its own relay.
  • bpeebles said:

    (skerew) ABSOLUTELY!! All the symptoms you describe point to the alternator (or regulator) being faulty. You do not mention the YEAR or MILAGE on your vehicle but alternators are a common failure item on ALL vehicles. The brushes or bearings will eventually fail.

    One way to VERIFY is to use a DVM (Digital Volt Meter) plugged into the 12V accessory outlet. The voltage under virtually ALL operating conditions should be around 13.8 Volts. (Anything less, and either the alternator or the regulator are faulty.) I would not hesatate to connect up my Fluke DVM and do some driving with all lights on to verify operation of the alternator. (I would not "GUESS" that it is the alternator because they are quite expensive.)

    There are other possibilties that may cause the symptoms you describe besides the alternator.

    There are several 'choices' when considering replacing an alternator. (New, remanufactured and rebuilt.) New ones are VERY expensive... trailing down to the cheeper rebuilt which may not last very long.

    BEWARE: There is a reason why alternators from Autozone-type stores have lifetime free replacement.... they fail quite often and NEED to be replaced. I have first-hand experience with these things and my labor is more valuable to me than that. After replacing an $80 rebuilt alternator several times (sure it was free replacement)... I ended up spending $250 for a NEW one that never failed again. As I said... my labor is worth too much for me to REPEAT the job over and over.

  • I just bought a used 03 Jetta for my daughter & we had similar electrical problems. My experience has been that is was related to a bad alternator as you 'bpeebles' indicate. My battery voltage was down to 10v but before I went down the path to replace the alternator, I had the battery tested & it had a bad cell, & I replaced it.
    The voltage was back where it should be & we were back on the road. I had an autozone tech check the alternator & tests indicated it was working fine. (I know, consider the source), but his explanation made sense.
    After saying all that, it happened again, but I haven't had a chance to troubleshoot it yet. I haven't charged the battery yet & the car won't start.
    Can the alternator be intermittently faulty?
    I didn't know there is a voltage regulator involved.
    I agree I need to get a list of ills from the dealer before deciding but I need to get it running 1st.
  • eliaselias Posts: 2,147
    yes the voltage-regulator and/or alternator can be intermittent. more likely the former. often the voltage-regulator is integrated with the alternator - not sure if that is the case with your car.

    it's also possible there is nothing wrong: if the car is mostly parked and is used only for short/few-mile trips it is expected that the battery would become discharged. to ensure a full-charge, use a trickle-charger overnight. Or, after starting it via jumper cables, drive at highway speeds for an hour or three.
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