Weird humming/singing from thermostat 2007 2.5T
Username
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    Results 1 to 3 of 3
    1. #1

      Weird humming/singing from thermostat 2007 2.5T

      Hi party people!

      So there's a coolant line that runs from the thermostat to the intake manifold. That little line is making a weird high-ish pitched noise like the flow might be restricted going into the intake. Have any of you heard of anything like this? I have a feeling I'm gonna have to dump the coolant and remove the intake manifold and look inside the hose. I'm 90% sure it's coming from there... but before I start taking apart the engine, I'd like some input from those in the know! Oh... and the car has 57,000 on it.

      Thanks!!

    2. Remove Advertisements

      Advertisements
       

    3. #2
      Junior Member TiGreyS60's Avatar
      Join Date
      Feb 2015
      Location
      New Cumberland, PA
      Posts
      73
      The area that you are talking about is part of the PCV system. The fitting that is on the underside of the intake manifold not only has the water line that you describe, but a small vacuum line that connects to that fitting. You really can't see it until you dissemble that PCV line. The possible problem is that this small line becomes brittle over time and and breaks. I would say that if you take that connection apart to look at it, if it isn't already cracked, it will. You can't really gain access to the area in question without removing the intake manifold. If you do indeed have a vacuum leak at this fitting, you need to have the PCV system fully serviced, as this can lead to other problems. The water line from the thermostat housing runs through the hard line of the PCV system and returns into the block on the passenger side. The purpose of this is to keep the oil vapors from the block from condensing in the vapor return line that goes to the intake tube going into the turbo.



      Last edited by TiGreyS60; 04-08-2017 at 09:41 AM.
      2007 S60 2.5T | Eibach Pro-Kit springs | Koni FSD Struts & Shocks | IPD Boost Gauge & Pod, HD Coil Packs, Rear Chassis Brace, Poly Sub Frame Bushings , HD Endlinks | EST Carbon Fiber Strut Bar, 3" DP, Touring Cat-Back Exhaust | Snabb High Flow Intake | do88 BigPack - Intercooler & Piping Kit | Brembo "R" Caliper Upgrade F&R | StopTech 330 mm Drilled & Slotted Rotors, SS Brake Lines | Hilton Stage 3 Tune

    4. #3
      Quote Originally Posted by TiGreyS60 View Post
      The area that you are talking about is part of the PCV system. The fitting that is on the underside of the intake manifold not only has the water line that you describe, but a small vacuum line that connects to that fitting. You really can't see it until you dissemble that PCV line. The possible problem is that this small line becomes brittle over time and and breaks. I would say that if you take that connection apart to look at it, if it isn't already cracked, it will. You can't really gain access to the area in question without removing the intake manifold. If you do indeed have a vacuum leak at this fitting, you need to have the PCV system fully serviced, as this can lead to other problems. The water line from the thermostat housing runs through the hard line of the PCV system and returns into the block on the passenger side. The purpose of this is to keep the oil vapors from the block from condensing in the vapor return line that goes to the intake tube going into the turbo.





      Thanks so much for the reply! I was afraid I was going to have to take the intake manifold apart.... I just replaced the breather tube when I noticed that was split in the middle.

    5. Remove Advertisements

      Advertisements