Oil marks on dipstick

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by C Clay, Jan 8, 2026.

  1. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    7,665
    3,940
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    I'm NOT using that crap. It's not worth the time. And it doesn't work.

    There's no point in changing the oil if you don't replace the filter also...
     
  2. C Clay

    C Clay Member

    Joined:
    Nov 24, 2012
    348
    67
    0
    Location:
    Lexington, KY
    Vehicle:
    2014 Prius
    Model:
    Four
    I actually use protect and restore and have reported no oil use between oil changes for about the last 10 oil cycle changes. But maybe antifreeze is mixing with the oil
     
    Gokhan likes this.
  3. C Clay

    C Clay Member

    Joined:
    Nov 24, 2012
    348
    67
    0
    Location:
    Lexington, KY
    Vehicle:
    2014 Prius
    Model:
    Four
    Hey there, thought I would wake up this thread and just ask a question. Last Friday I went out and added about 16 to 20 ounces of coolant, I thought that was strange. I haven’t really had any “hard starts” or any codes that come up or check engine light.

    In general, I’m thinking I may need a head gasket, but I’m not so sure. or not yet anyway. I’ve probably driven about 1000 miles in the last seven days, I drove 70 to 80 miles an hour around 300 miles one night, no issue. I haven’t had an issue at all… Except for adding another 16 ounces or so of coolant yesterday.

    I did do a combustion leak test, it didn’t report anything. Did it multiple times over 2 days.

    One thing I have reported is that when I first get in the car seems like I hear some coolant moving through somewhere behind the dash that I’ve never heard before. I don’t see any leaks, but what I need to do when it warms up is many take off the underpinnings of the car so that I could see anything that could drip and be caught on the plastics. Also I can check under it well. Also I have tried that coolant dye and black light to detect leak and I don’t see anything.

    Now- when I added 16 oz of coolant yesterday, I Did have a hard start- up and a P0301 code. Is it safe to assume that I definitely have a failing head gasket given what I have reported here?

    I’m just stumped how so the missing coolant is the bigger issue than the misfires .

    (2014 Prius, 360,000 miles, head gasket replaced 110,000 miles ago. Doesn’t burn oil. Have cleaned EGR, intake manifold, replaced PCV valve)