Is my cars engine blown? ?

I just bought a 1965 Cadillac Seville with the original 7.0 liter 429 cubic inch v 8 engine in it the owner said he drove it years ago but put synthetic oil in it and the engine started knocking and after that he parked it and stopped driving it I tried starting it and it starts instantly but when it runs it knocks really loud but when I crank it I don’t hear any banging or knocking only when it runs I was thinking it might be the oil pump that is clogged and isn’t lubricating the engine heads and when we took out the valve covers they where bone dry and only one head was nearly getting oil to it what could be wrong with this engine? Would it have to be rebuilt or change the oil pump in it? Please help thank you 

7 Answers

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  • don r
    Lv 7
    4 weeks ago

    Dry valve train indicates oil starvation and that would cause severe bearing wear. The oil pressure light should be lit. The damage is done. Maybe replacing the oil pump can restore lubrication, but the worn out bearings that allow the connecting rids to wander around and knock will not heal. Eventually this engine will blow up. It can be rebuilt by a machine shop. If you really want the car, it might be better to replace the engine with a rebuilt one. That will cost you a barrel of Cadillac dollars- those are much bigger than Chevy dollars. Good luck.

  • Erik
    Lv 7
    1 month ago

    The knocking means that the engine is severely damaged. It will eventually stop running. The engine needs to be rebuilt. $$$$$$$$$$$$ And with an engine this old, it might be really difficult to get the parts you need.

  • Ron
    Lv 7
    1 month ago

    It's time for a rebuild and that has nothing to do with the use of synthetic oil.

    https://www.caddydaddy.com/shop-parts/engine-items...

  • Anonymous
    1 month ago

    EPIC FAIL

    Cadillac did not make a Seville model in 1965.

    Perhaps you mean DeVille . . . . but if you don't even know what kind of car you just bought, there's no point in discussing engine problems.

    added@ Ivansatrip: then you click on "update" and add to the question - or cancel it altogether

    • ivansatrip1 month agoReport

      Epic fail these nuts tf I knew I meant deville dummy and I tried changing the question and it didn’t let me after I posted it

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  • 1 month ago

    The big ends have gone so expect to pay a fortune for repair. Why do you need a seven litre engine polluting the atmosphere anyway?

    Scrap the old wreck and buy an economical runaround.

    • Erik
      Lv 7
      1 month agoReport

      I'm happy to hear you don't care what the cost will be, because it will be A LOT, more than the car is worth

  • Anonymous
    1 month ago

    You haven't told us the mileage but I imagine it's sky high with a car older than 50 years. From what you have said a rebuild is inevitable. A good mechanic will replace all the main bearings, oil pump and any other worn components. However, the fact that it starts and runs at all is encouraging. The excuse from the seller about synthetic oil is bullshit as any good mechanic will confirm.

  • Bill
    Lv 7
    1 month ago

    Get a mechanic to look at the car. The engine has probably been damaged from poor lubrication so that it would have to be rebuilt or replaced.

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