I have an engine knock in my 04 holden rodeo with the 3.5l petrol 6ve1 engine. Seems to knock on idle dissapears with acceleration.(or just gets muffles by exhaust noise) any help on attempting to diagnose it would be appreciated.

  • Welcome to Motor Vehicle Maintenance & Repair! – Pᴀᴜʟsᴛᴇʀ2 Apr 13 '18 at 10:44
  • There isn't enough detail to this question. Can you tell what area the knock is coming from (top or bottom of engine)? What is the oil level and condition? When was the last time it was changed? Is the "check engine" light illuminated? – CharlieRB Apr 13 '18 at 12:25
  • Are you sure it’s a knock and not more of a ticking? – sjfklsdafjks Apr 13 '18 at 13:30

When it comes to engine knocks, I like to verify the worst possible scenario 1st, and that is rod knock. From a professional view, if this is the cause of the knock, depending on the value of the vehicle, is a game changer for a lot of people.

With the vehicle running and knocking, disable spark from each cylinder one at a time. If the noise suppresses on 1 of the cylinders, then it is rod knock.

By disabling spark, you are changing the force from driving (piston moving the crank) to driven (crank moving the piston) and there should be a definite change in sound if there is a major problem.

| improve this answer | |
  • Doing an oil change (and filter) tomorrow and ill post vid afterwards. It seems to be toward the back of the top of the engine. Using a tonne of oil. Idleing a bit rough. Its consistant deep tick if that makes sense. Ive had lifter noise on other cars and its was lighter/higher sound and would increase with revs. This is consistant but from cliPs ive watched no where near as loud as rod knock. – Andrew Poole Apr 13 '18 at 14:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.