I changed the intake gaskets top and bottom along with valve cover gaskets on my Ford F-150. After I finished it was hard getting started but I finally got it started and now it sounds like the valves are knocking. I changed the oil, but they still sound like they're knocking. Do you have any ideas what could be wrong?

  • Did you clean the hydraulic lifters? Aug 23, 2019 at 17:41
  • did you put enough oil? maybe lifter tick from the engine being low on oil? May 7, 2023 at 6:20

3 Answers 3


I'm not sure how the F-150 is setup but if you had to remove the injectors to remove the valve cover or intake, check that the injector seals are still on and the injectors are down tight, or this can create a knock.


You've either got the valve covers on the wrong side or it's turned around backwards.

  • 1
    Can you expand on why valve covers positioning would make the vehicle hard to start AND cause knocking? Dec 21, 2018 at 17:45
  • I don't remember which car maker it was but you could turn the valve covers around backwards and they would still bolt onto the heads. If you lay the valve covers down on something flat and level and get your eye down level and look, you'll see that the valve covers are raised slightly on one side so the rocker arms wont hit them when the pushrods open the valves. The pushrods need more clearance so they get the higher side of the valve cover. Hard to start as in Cranking Slow is Ground wire off from head to firewall Or valve covers pressing against rockers. Give me make, model, year & motor
    – Arlie
    Dec 23, 2018 at 7:01

What year Ford is it? If you did not loosen or take off any of the rockers about the only thing it could be, unless something fell in, would be the valve covers on wrong. As to the hard starting it may be a vacuum issue. With the engine running spray some carb cleaner around the fittings and throttle body. If a change in rpm occurs there's the leak.

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