4.6L Northstar engine, while in drive, low end engine knock. Once in park the knock goes away. What is it?

Cadillac 2000 STS. 4.6L Northstar engine. Automatic 4 speed transmission. Engine knocking when in drive but sound goes away when in park. Any suggestions where to start or what to check?

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  • 1 decade ago
    Best Answer

    the knock you refer to is common with the northstar, it is a rod knock, it is most audible when in gear due to loading the engine no load is on the engine in park

  • 1 decade ago

    Try performing a oil change on that engine and instead of one off the litres of oil add a litre of Lucas oil treatment to it.

    Hope that helps and best of luck.By the way you might be very happy and surprised in just how well that product works.Here's a great example I have a buddy he had a van that was making a heavy duty engine knocking sounds as he drove it into the shop for a brake job.Later a few months had gone buy and the same mechanic was once again working on the van changing the gas filter and he asked hey no pinging sounds , what you do change the engine? my buddy said no he had added Lucas to the oil change and that fixed it right up.He now swears by Lucas and he loves the product all bec it actually works , keep in mind that many car manufactures actually promote and even sell Lucas oil treatments and their products.

    I know several ppl that have all had such things occur , plus myself I've seen how Lucas can increase horse power or bring back some of the engines gusto.

  • 1 decade ago

    wow and bob have good answers for you. We use Lucas oil treatment at work and it has definitely extended the useful life of many a beat engine in our fleet.

  • 1 decade ago

    Could be a connecting rod or the bearing. Have you been low on oil recently?

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  • 1 decade ago

    hope its not engine possibly loose torque converter

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