Welcome to PriusChat

We'd love to have you join our community and participate in the conversation! Sign up for FREE today.

Sign Up

engine oil leak

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by prscht, Jun 14, 2010.

Social Buttons

  1. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Hi all,
    During 2 engine oil changes ago (at 51K miles) i noticed a drop of oil residue on the backside of the engine block above the oil pan. It is dark brown and feels like engine oil. I wiped it clean for further observation. During the last oil change 1 week ago at 56K miles, the same spot is again wet with oil. See pictures #1 and #2.

    I wiped it clean and drove for 4 days then raised the car and checked again. Same thing-a drop of engine oil is hanging on the same spot, see picture #3. This leads me to think there is an oil leak in that area. I don't know where the leak is from, can someone help to identify potential sources? The camera is facing up from under the car. BTW there is oil residue on the other side of the "big metal block" as well.

    During all this time the leak has never accumulated enough to leave spots on pavement. I did all oil changes on my own. I have not dripped oil when filling on top.

    The location of the oil leak is above oil filter and oil pan, so it couldn't come from either places. Facing foward with the front of the car, the oil residue is on passenger side, directly above the backend of oil pan, on the backside of the engine to the right of the exhaust manifold heat shield which is visible in picture #1. When looking up from under the car directly past the oil spot, the windshield wiper cowel is in the way so it's not possible to spot the leak from above. Can someone identify the source of the leak based on the pictures? Is this serious and do I need to take it to the dealer?

    A second question: in the last picture (#4), does it look like a cracked engine block? I took this picture in the vincinity of the oil leak while inspecting with a reflecting mirror. The "cracked" location is below the aforementioned oil leak.

    My car is a 07 with 57K miles and always used Mobile 1 5W30 with Toyota filter every 5K miles. I bought the car new and it has never been in any kind of collision. Thanks for any insights anyone can provide!

    Attached Files:

  2. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    Messages:
    4,084
    Likes Received:
    413
    Location:
    Bahstahn
    Your Vehicle Year:
    2004 Prius
    Model:
    N/A
    It does look about in the right location to have been caused
    by a minor oops during filling. Short of pulling the cowl,
    you might be able to sneak a small mirror over the top where
    the oil fill is and look down the upper half, although the
    exhaust shield will be somewhat in the way.
    .
    Otherwise, suspect valve cover gasket or the like.
    .
    The minor surface crazing seems pretty normal; a side-effect
    of the casting process or something. All of the alloy castings
    on mine [incl. the inverter] have it to some extent.
    .
    _H*
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    If the oil leak is not bad enough to drip on the ground, then it is not serious and I would not worry about it.
  4. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Thanks for the feedback Hobbit and Patrick. The thing is that the drop of oil would reappear every time after I wiped it clean, so this appears to indicate it's coming from the engine. While doing oil changes i have never spilled from the top out of the funnel. I will remove the cowl this weekend to have a look from the top.

    My car has 57K miles - still within the 60K power train warranty, if the leak is from the engine (valve cover, etc) would it be covered under the warranty?
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    I think the oil leak would be covered by the powertrain warranty, but I suggest you read the warranty terms and satisfy yourself this is the case. Then see if you can find out where the leak is coming from.
  6. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    The powertrain warranty does cover engine gaskets and seals.

    I took the cowl off today but it's still hard to see the back of the engine when looking straight down from the top as the valve cover lip and exhaust manifold heat shield are in the way. But I was able to feel around the valve cover and there was no oil around the gasket.

    Then i went under the car and it appears oil was leaking from several spots: upper oil pan gasket was wet at the location indicated by the lower red circle in the diagram and a spot near the #1 cylinder exhaust (upper red circle). THe middle red circle is where the surface crazing is, and that area is also wet.

    I felt around the timing chain cover, there doesn't appear to have any leaks around the cover gasket.

    Has anyone else noticed oil in these areas? Patrick you mentioned if the leak is minor then it's not serious - but will it get worse? Should I take it to the dealer? Is it a big job to fix this? I will attach some pictures soon. Thanks.

    Attached Files:

    1 person likes this.
  7. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    Messages:
    3,006
    Likes Received:
    688
    Location:
    Ballamer, Merlin
    Your Vehicle Year:
    2008 Prius
    prscht,

    Thanks for your dogged perseverance in this matter. :rockon:
    We will all be smarter at it's conclusion, no matter the outcome. :cheer2:
  8. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    OK on more careful inspection, the leak came from 2 places: 1. upper oil pan gasket like i said before, 2. timing chain cover near the exhaust manifold.

    So how long a job is this at the dealer, to change the 2 gaskets, if these need to be fixed? Is there supposed to be oil inside the timing chain cover? Thanks.

    The picture shows the leak from the upper oil pan seal. I can't get a picture of the timing leak from timing chain cover.

    Attached Files:

  9. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    It's great that you were able to figure out the location of the oil leaks. Looking at your marked-up drawing, is it possible that the oil leak is just from the timing chain cover, and oil is dripping down on the oil pan location?

    My guess is that the repair might take 4-6 labor hours if both gaskets have to be removed and replaced. If you had to pay for this, I would say to defer the repair until the oil leak worsens considerably. Since it's covered under warranty, I would have the leaks fixed now.

    Yes, there will be some engine oil inside the timing chain cover because oil is splashing around the valve cover, while the timing chain runs around the camshaft sprockets and down to the crankshaft sprocket. The engine oil pump is also located on the timing chain cover; maybe that pump is leaking?
  10. vertex

    vertex Active Member

    Joined:
    Mar 27, 2009
    Messages:
    669
    Likes Received:
    116
    Location:
    new york
    Your Vehicle Year:
    2006 Prius
    Model:
    N/A
    Sometimes just tightening the bolts will do the trick.
  11. bedrock8x

    bedrock8x Senior Member

    Joined:
    Jul 8, 2008
    Messages:
    1,472
    Likes Received:
    124
    Location:
    California
    Your Vehicle Year:
    Other Hybrid
    I think the valve cover gasket is leaking and cascades down to the oil pan, try tighten up the bolts. If the bolts have a shoulder to prevent over tightening, put a washer on to push the cover down or get a new gasket.
    The is a common problem for Camry V6 engines, this may be rare for Prius engines.
  12. BAllanJ

    BAllanJ Active Member

    Joined:
    Dec 9, 2008
    Messages:
    658
    Likes Received:
    68
    Location:
    Kingston Ontario
    Your Vehicle Year:
    2009 Prius
    Model:
    N/A
    I may be out to lunch here, but I have a vague memory of once hearing that a stuck pcv valve can cause multiple oil leaks by the crankcase getting overpressured.
  13. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Good suggestions here. the valve cover gasket was the first place i checked after Hobbit first suggested it. With the cowl and water catch basin removed, using a mirror and the feel of my fingers i went around the valve cover and it was all dry, no sign of leak or oil grime.

    Then i went under the car to look up past the oil pan. with the cowl removed more light came through and made it easier to see with a mirror. there was oil grime in the timing chain cover area around where exhaust comes out of #1 cylinder, as the upper most circle shows in the marked-up diagram i posted before. Then there was another wet spot at one of the corner bolts that hold the upper oil pan to the block - this one Patrick mentioned could possibly be drippings from the upper leak point.

    Then i did remember from reading here that a stuck PCV valve could cause leaks. So I took mine off and it does rattle clearly, so i put it back. But there was grime on the valve cover near the PCV valve/tube and there was what looked like caked oil residue on the end of the PCV valve that resides inside the valve cover, I will post some pics later.

    Just out of curiosity, does the dealer need to drop the engine to replace the timing chain cover gasket?
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A


    No, this can be done with the engine in place.
  15. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Thanks for the reply Pat.

    So while all this is happening, today i parked the car on the street and I think i might have forgotten to power it down (headlights were on at the time). When i returned 4+ hours later, headlights were very dim, car was off and would not power on into any mode. Parking button light was on, clock was on but barely visible. Doors were locked (does this mean i DID turn the car off? because Prius does not allow locked doors in Ready mode), and smart key didn't work. Every time when I press the power button the check engine light came on.

    So I said shit, i drained the 12V. I got the car jumped, thank god the HV battery did not drain. Then i wanted to check the 12V voltage on the MFD but forgot how. So I drove 25 minutes highway home so i can look up the procedure to check the 12V voltage. Is 25 minutes at 60 mph enough to recharge the 12V battery?

    Now I'm trying to figure out what happened:
    All 4 doors were locked when I returned, this means car was IG OFF at some point. With doors locked headlights would turn off automatically, regardless of switch position. But when I came back headlights were very dim and tails lights were also on with the car OFF, I had to use the little metal key to unlock the driver door. what could have happened?
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A


    Your speed of 60 mph is irrelevant, as the 12V battery will be charged at the same rate whether your speed is 0 or 106 mph, as long as the car is READY. 25 minutes is not enough to fully-charge a good battery, you'll need to keep the car READY for more like 8 hours, or else hook up a battery charger if you have one available.

    My guess is that you exited the car via some door other than the driver's door, if the exterior lights remained on.
  17. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Thanks for the quick reply Pat.
    I just measured the 12V, you are right, it's only 12.75V. I do not have a charger. 8 hours to fully charge - can this be done cumulatively through everyday driving, or is it best to leave car in Ready overnight?

    I did not climb out another door, I came out the driver door. Could this scenario be possible: left car on with lights, car shut off automatically to protect HV battery (3 blue bars after jump start), locked itself automatically after 30 seconds, but did not shut lights off.
  18. Bob64

    Bob64 Sapphire of the Blue Sky

    Joined:
    Apr 9, 2007
    Messages:
    1,530
    Likes Received:
    74
    Location:
    Virginia
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Short answer: Depends on what you mean by left car "on".
    If on = ready mode, then no.


    The HV battery is only used in Ready mode. If the car was left on in ready mode, then the car would automatically startup the engine (unless left in neutral) in order to supply power to the HV battery. The HV battery would also power all accessories including the lights in this mode.

    If you weren't in ready mode (accessory mode), then only the 12v battery is used even when it partially boots up and shows the HV battery level (2 presses of the power button without the foot on the brake when the car is off).

    My guess, you weren't in ready mode (perhaps accessory mode), left the lights on and locked the car. Headlights gradually ate all your 12v battery charge, so it was insufficient to boot the computers.

    Keep in mind that you may have permanently damaged the lifespan of the 12v lead-acid battery - lead-acid batteries do NOT like to be emptied - eats away at the lead/metal plates inside of it.
  19. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    Messages:
    13,341
    Likes Received:
    3,186
    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A


    12.75V is actually quite good. However this might be due to surface charge. See what the voltage on the 12V battery is tomorrow morning, before you start the car.

    It would be best to leave the car READY overnight if you can do so without causing a safety or security risk. Otherwise, if you drive 50 minutes each day, that should restore the battery charge over several days of driving.
  20. prscht

    prscht New Member

    Joined:
    Mar 8, 2010
    Messages:
    33
    Likes Received:
    2
    Location:
    Parsippany, NJ
    Your Vehicle Year:
    2007 Prius
    Model:
    N/A
    Update: i took the car to the dealer, even though both the shop foreman and service writer saw the hanging oil drop and felt wet oil in the areas i indicated, they insist putting in a small bottle of dye in the engine oil and have me drive 500 miles, then they will check with UV light to be certain of the leak and the location. Then they will file claim with Toyota warranty.

    They tell me they are following warranty claim procedures for oil leaks. It does make sense but this will push the mileage even closer to 60K (58300 mi right now) and that concerns me. How long does it take Toyota warranty to process a claim? Can they usually approve/reject over the phone after receiving all information in the same day? I have never dealt with car warranties. I'm thinking about having them file a claim right now so the next time i come in they can just supply the additional dye test results and get a decision right there (saves me another trip).

    And how much control or say does the dealer have in convincing Toyota to honor the claim? So far the shop foreman took pictures, pulled all dealer visit histories and carfax report to make sure it's not in a collision. Thanks all.
Similar Threads: engine leak
Forum Title Date
Gen III 2010+ Prius Main Forum Transmission leak, engine has to come out... Nov 14, 2013
Gen II Prius Main Forum Engine radiator bleed valve leakage Nov 12, 2013
Gen II Prius Care, Maintenance and Troubleshooting water pump leak (not the recalled one, but the engine one) Jun 20, 2012
Gen II Prius Care, Maintenance and Troubleshooting Water pump #2: One was recalled, and now the gas engine one is leaking! Mar 3, 2011
Gen II Prius Care, Maintenance and Troubleshooting Pink stuff leaking from engine May 22, 2009