, i got a knocking/ticking noise when the engine is warm at the idle, at around 650rpm, it's been one year the engine make that sound and it has not become worse nor better, i noticed that the idle when engine is col is about 1500/1700rpm, i got some check engine O2 sensor, but i read on some forum people with the same problem without any check engine light and didn't find the problem , i use 10w30 mineral oil, and the noise seems stronger when waiting at stop light with the foot on the brake, but it make also make it on park or neutral, do you guys have some idea what is the probleme. Sorry if my english is bad, feel free to ask question or clarification
My daughter's LD9 also does this. Best I can figure, it is the torsional vibration between the balance shaft gears.
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Mine's been doing the same thing for going on a year now. It Started doing it after I had the timing chain, chain tensioner, chain guides and water pump replaced. I've been drivning it like this for well over 4000 miles with no problem. It only does it below 1000 rpm and only when warm. I use the GM factory recommended 5w30 because thicker oil doesn't flow as well and it's critical to get oil flow to the timing chain tensioner immediately upon start up because the tensioner operates of oil pressure.
The old "thicker is better" doesn't jive well with the newer cars because the tolerances/clearances between the internal engine parts i.e. bearings, rods, etc.. is very tight and thick oil doesn't flow between the tight clearances very well. That's why some of the newer bmw's and mercedes are using 0w30 from the factory. Ford had issues with the chain tensioners failing on their mod motors and found that the problem was caused by people who were using the wrong viscosity of oil and the wrong oil filters. People were using oil filters such as fram that didn't have anti drain back valves in them and as a result it takes longer for oil to start flowing upon initial start up.
It's always best to use the exact same type of oil and oil filter that the vehicle came with from the factory. In out case it's the AC Delco Pf46. and it does have an anti drain back valve. DO NOT get the ac delco filters from walmart or any ac delco filters with a part number that ends with "e" They're not the same internally and they have plastic inside of them that could break, lodge inside the engine and destroy it.
As for the noise, My bet is that the chain tensioner isn't functioning properly and therefore there is slack in the chain at low rpm and thus making the ticking noise. Mine sounds similar to a diesel when idling below 1000 rpm and at operating temp. The best route is to swap to a mechanical style tensioner from a 96 z24. You have to remove the stud on the block that holds the hydraulic chain tensioner shoe in place in order to swap to the mechanical style tensioner. As far as I know that's all that's too it. I still have yet to do this to mine, but plan on doing it soon. Make sure to get Genuine GM parts or Cloyes. I got the whole timing kit from PCI on ebay that included the chain, chain tensioner, chain guides, water pump and cam sprockets, but the chain tensioner doesn't work properly and it's the hydraulic tensioner (I Should have swapped to mechical tensioner when I had the first chance)
