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Virtual Wrench
Virtual Wrench, Master Mechanic
Category: Car
Satisfied Customers: 14620
Experience:  35 years/Master Tech. Foreign and Domestic
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2001 isuzu trooper: 3.5L..loud knocking noise..smooth..gas tank

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I have a 2001 Isuzu Tooper with a 3.5L engine. Engine has a loud knocking noise but runs relatively smooth. I put Sea Foam in the oil and two cans in the gas tank but the noise will not go away. What do I do next?

The first thing we need to do is try and establish whether it is what we call a "low end knock" which sounds deeper in tone, such as a knock on wood, and the other type is a clicking higher pitch noise like it you tapped two spoons together,,,follow me?

With that info can you determine if it has a low end knock?
Customer: replied 5 years ago.
The noise itself seems to be coming from the top of the motor. The sound is more like two spoons, not that low banging sound

That is much better than a rod knock. Be right back..


The valves will need to be adjusted, and to do this, there are shims that are installed between the cam lobe and the tappet (lifter). It is a pretty involved procedure to measure then replace with the correct thickness shim. I dont know your mechanical abilities but it might be best to let a shop handle this for you.


If you have any further questions or need more help at all please feel free to reply. If not, Please remember we use an honor system and you must click on accept for me to receive credit for assisting you.
Virtual Wrench and 3 other Car Specialists are ready to help you
Customer: replied 5 years ago.

Thank you. I'll take it to a mechanic but this sounfds very positive.

My pleasure!

Thank YOU for asking!