How Do You Make A Connecting Rod Knock Less Noticable In A High Millage Engine.

Posted in Crank, Oil and Piston | Asked on May 11, 2010

This problem happens at start up but I have also noticed it when the car is in park or when their is no laod on the engine. It only seems to happen when you rev the engine to 1500 rpm’s. Oil pressure is okay. Car is a 1993 Pontiac Grand Prix with a 3.1L LHO V6 it has 158,638 miles and I use 10w30 castrol oil and fram ultra filters
I have tried lucas oil and thats why my engine has this knock.
The engine will knock only in the morning for maybe 3-4 seconds then it goes away and it will not knock on a hot reastart. If I rev the engine it will not knock. There is no metal shavings in the oil or inside the oil filter.

There are 11 Answers for "How Do You Make A Connecting Rod Knock Less Noticable In A High Millage Engine."

  1. mtl_25_m says:

    sounds like a bad lifter to me

    try some lucas engine oil/treatment or whatever.

    it’s like 10$/litre and looks like molasses but everyone i talk to about truck engines swears it saves old engines

  2. joe z says:

    try “motor honey”

  3. mushthissel says:

    40 wt. oil and ear plugs.

  4. eric.s says:

    I assume that you don’t want to dismantle the engine and fix it correctly?

    Try a thicker oil, or oil additive. The prior post mentioned an apparent British product. I haven’t looked lately, but STP Oil Treatment used to be around in the US and was a thickener.

    This solution might cause new long-term damage elsewhere, since you would be deviating from the manufacturer’s specification, and areas of the engine would probably not receive fully adequate lubrication, leading to eventual excess wear.

  5. Legacy says:

    You know, there is an oil additive from Lucas, which makes some real good products. This product is so good that it might just do the trick. Try it out. It’s less than $10.00. Worst case scenario is that you added a great additive to your engine that actually helps it out and will just help lubricate your engine and if you actually add one to every oil change, you can even prolong the life of your engine. If that doesn’t work you’ll most likely have to replce it which can get costly. you can get it at any convenient auto parts store like Advance Auto Parts or Auto Zone.

  6. mastertech35 says:

    You are going to have to rebuild the engine. This is not going to go away. It will get worse, and cost alot more. Remember the old Fram oil filter commercial: pay me now; or pay me latter. the cost of a rebuild on a 3.1 around $2400.00 out the door.

  7. mojo3120 says:

    It may not be rod knock. There are other things that sound a lot like rod knock. If it is rod knock there’s nothing you can do but stop driving it before you throw a rod which will be pretty soon.

  8. mrknositall says:

    As others have said it may not be a rod. Does the noise go away under a load? If not, it is probably a lifter. STP may quiet the knock down but it won’t make the problem go away. Unlike others here I wouldn’t suggest a rebuild; an engine could run for another 50-60k after a knock appears.

    RULES FOR ADVANCED MILEAGE ENGINES

    Always allow an adequate warm up before driving.
    Never free-rev the engine.
    As engines advance in mileage, it becomes more and more important to change the oil regularly.
    Check the oil twice a week.
    Pay attention to your guages/idiot lights.
    Your car is old; treat it that way.

  9. Dbl_Monday says:

    Re-build or re-place..in either case, start using Amsoil. Put in the engine,tranny,diff. what ever needs lubrication..

    Once it starts to knock, it’s only a matter of time..

  10. blerjer says:

    Try Marvel’s Mystery Oil if it is a lifter. Runs in the gas tank or in the crankcase. Deisels too.

  11. biohazardmind says:

    well the infamous rod knock have you checked the flex plate? The steel disc between the engine and the torque convertor. They crack and make a terrible racket you can unbolt the convertor and slide it back into the transmission then pry on the plate not hard if it is cracked you should be able to tell. and yes they don’t make noise under a load but with no load they make a noise that sounds just like a rod knock.