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  1. #1
    Join Date
    Nov 2014
    Location
    USA
    Posts
    69

    Default Coolant leak as car cools down

    I've got a coolant leak in my 2003 XC70, and the odd thing about it, at least to me, is that the leak doesn't appear while the car is running and at full temperature/pressure. The leak appears about 2.5 hours after the car is parked. It's dripping on the passenger's side.

    For example, I drove the car for 20 minutes today mostly at highway speeds. Parked 10-15 minutes. No leak. Drove another 20 minutes on highway and stopped at a pharmacy for about 10 minutes. Checked for leaks. No leak. Drove home. 2.5 hours after the car was parked, it's dripping, leaving a small wet spot on the driveway.

    Then once the car is pretty completely cooled down (four hours), the leak stops.

    Any ideas what would cause this kind of leak?
    Last edited by Silvestris66; 03-01-2022 at 02:24 PM.

  2. #2
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    576

    Default

    Have you noticed if the level of the coolant in the reservoir is low? Have you had to add more coolant yet?
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  3. #3
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,059

    Default

    You're certain that it's coolant?
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (114K, Michelin AS3+, LiquiMoly 0W40)
    2005 MB SL600 (50K, Michelin AS4, Mobil 1 0W40)
    2004 V70R (six speed M66, Mobil 1 5W30)
    2002 V70-XC (275K, HPL Euro 0W30)
    2002 V70-T5 (216K, IPD bars, Bilsteins)
    2001 V70-T5 (120K, IPD downpipe, cat back and other mods)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  4. #4
    Join Date
    Nov 2014
    Location
    USA
    Posts
    69

    Default

    Quote Originally Posted by Xfingers View Post
    Have you noticed if the level of the coolant in the reservoir is low? Have you had to add more coolant yet?
    Yes, I have had to add more coolant twice, but not a lot. I got an alert on the instrument cluster.

  5. #5
    Join Date
    Nov 2014
    Location
    USA
    Posts
    69

    Default

    Quote Originally Posted by Astro14 View Post
    You're certain that it's coolant?
    Yes. I've been working on my own cars since the 1980s, but mostly GM. Not a Volvo expert.

  6. #6
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,059

    Default

    Well, if you've had to add coolant twice, then you should be able to find the crusty deposit that a slight leak will leave. May have to go hunting with a mirror and a good light.

    Most cars leak under pressure. After cooldown, pressure is reduced.

    Immediately after shutdown, temperatures (and pressures) tend to peak.

    I wonder if it leaks only under very high temp, but it doesn't trickle out for a while after that...
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (114K, Michelin AS3+, LiquiMoly 0W40)
    2005 MB SL600 (50K, Michelin AS4, Mobil 1 0W40)
    2004 V70R (six speed M66, Mobil 1 5W30)
    2002 V70-XC (275K, HPL Euro 0W30)
    2002 V70-T5 (216K, IPD bars, Bilsteins)
    2001 V70-T5 (120K, IPD downpipe, cat back and other mods)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  7. #7
    Join Date
    Jul 2010
    Location
    Rugby UK
    Posts
    427

    Default

    This could be a gentle warning the head gasket is on the way out. I had several isolated bouts of that atwo years ago. This fall I noticed on the induction side of the block small crystaline structures (cold engine) after a frosty night. I think it was fine coolant spray reacting with the aluminum block. Taking the head off on a RHD car is a pain there are far more obstructions underneath on RHD layout. I am still working out how to undoo two of the heat shield bolts.

  8. #8
    Join Date
    Nov 2014
    Location
    USA
    Posts
    69

    Default

    I was having a hard time pinpointing the leak, so I took it to my mechanic, whom I trust.

    Solution: Leaking water pump.

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