Tapping Sound on Cold Start

[Jerry Bransford]

I love rotella in the 4.0, keeps it quiet and clean.

Please understand I'm not trying to argue or pick a fight, but so does my conventional Valvoline 10W-30.

Today's multi-weight engine oils are superb, even Walmart's house brand... it doesn't take a special oil to provide superb protection to our engines. In 52 years of driving, I've literally never had an internal engine problem and I've never run anything but a conventional motor oil like Valvoline, Castrol, Shell, Mobil, etc.

 

[Bill]

Thanks Gents. Just wanted to post an update. I changed out the oil filter but it did not resolve the issue after driving it for a couple of days. I then drained the oil and fished a small magnet through the oil pan drain hole and swept the bottom of the oil pan (lowest part of the oil system) and swept the oil pump uptake screen. Upon removing the magnet after several repeats, the attached photo reveals only two tiny flakes of metal that appear rusted. This effort was to determine if broken metal parts from piston skirts found their way to the bottom of the oil pan. The fact that the particles are so tiny, combined with the rusted nature of them, tells me they likely found their way into the system when I removed the valve cover to inspect the lifters, push rods, and rocker arms. I realize this is not a perfect substitute for dropping the oil pan and inspecting the entire bottom of the pan, but having just put a new oil pan on in December, I did not want to go through that drill again.

 

[Bill]

So I am ruling out piston skirts. I listened carefully using a stethescope to various locations on the valve cover, timing chain cover, and under the engine to isolate the sound. It seems to me it is eminating from the valve cover area. My best guess is that upon installing the new lifters, it changed some characteristic in the valve train resulting in more, rather than less noise. At this point I'm going to keep running it as it is. I cannot say if the sound will resolve over time or not, but the engine has good power and, once run for about five minutes of driving, sounds like a new engine. I will, however, combine the oil with 20% MMO about 200 miles or so before the oil change interval, then do an oil change. I noted some advice in favor and some against this, but I cannot imagine it will harm the engine in any way, so I figure it's worth a try.

 

[Chris]

My best guess is that upon installing the new lifters, it changed some characteristic in the valve train resulting in more, rather than less noise.

Very possible indeed. I've seen that happen with all sorts of mechanical things in the past. You have something mechanical with a lot of miles / use.

I have the exact same problem as you and I honest to goodness CAN NOT figure it out (just like you). However, since it only happens for 30 seconds upon startup, I just forget about it. I will try the MMO next time I change my oil as @mrblaine suggested to me on a phone call. We'll see if that works.

Like I said, I am the biggest non-believer in additives, but if Blaine (who is the guru of TJs) says it worked for him, I will at least give it a try.

 

[NICHOLAS MATHER]

Old thread, but for anyone looking at this trying to figure out the tap sound....

Mine had it, usually lasted about 5-10 seconds before going away. Using a quality 10w30 with the wix filter.

tried the marvel mystery oil and it was gone when I went to start it up cold next morning.

Usually don't waste my money on any additives...but mr blaine and Chris endorse the MMO for this particular symptom, figured id try it.

Used about half a quart, might run it a week or so and then do an oil change, see if its gone permanently.