first thought: I had my heads redone about 1200 miles ago. I know the mechanic did not keep track of the pushrod position, unless he wrote the position on each pushrod with a sharpie or something. When I went to check in while the heads were off, they were sitting in a pile. He is a rover specialist and has been doing DII heads for over 10 years.

Now onto the issue:

at cold start (12+ hours sitting in the current 80-90F ambient temps), I get this knocking sound for about 10-20 seconds. It sounds like low end knock. I am not sure what exactly it is, but my first conclusions could be bad oil pressure at start, or the because the pushrods were not put back in their original locations (although OI don't know why it would take 1200 miles for the noise to show up if that's the case). previous owner claimed to have replaced the oil pump in 2016 during the engine install, so it should not be the original.

You can hear the sound kind of underneath the sound of the exhaust in the video below. I was out of town all weekend with my truck sitting, so this is a 5 day cold start. I was expecting the sound, so I had my camera rolling already when I started it. I backed up about ten feet, got out and put the camera underneath, and then got back in. by the time I was driving forward, the sound was gone. It only recently has done this, and I'd say not every single time I'm running it. it does not do it after the first 30 seconds of a cold start for any reason while once to operating temp, whether idling or driving, or revving hard. I can rev it up in park after it goes away and it does not make any noise.

My first step is going to be switching to rosella 15w-40 and a new filter (auto store filter recs anyone?). I'm currently running liqui-moli 10w-40. Oil was last changed when the heads were done.

the noise is most loud at 5 seconds in and it is the low sound. the higher pitched pinging noise are the magnaflow cats.

I did replace the power steering pump about two weeks and 200 miles ago. Not sure If that could be from my pulley, but everything else was on tight, although I did not torque anything in the process. I just got it tight and then did a 1/8" turn tighter as the video on Atlantic British shows.

absolutely zero leak spots on the ground on my smooth concrete carport floor over those 5 days.

Any ideas?

 

I have a similar noise at cold start and isolated it to the drivers side cat using the stick to ear method. I have decent oil pressure at cold/hot and the bell housing and oil pan do not transmit the noise. Only the left cat. Mine are original or at least LR cats and look original.

 

I'll put my stethoscope to it tomorrow morning when I crank it. That would be huge relief. I installed these cats about 500 miles ago and the noise was not present prior. I really want to get a least another year of daily driving before I have to do any low end work, after putting so much into it in the past 6 months getting the top end and exhaust sorted.

 

I run the full synthetic Rotella 15-40 with an oversized Wix filter, I believe it's 5151? Something like that it's the only filter combo that's made up with 1s and 5s lol

 

right on. I'll pick that up this weekend. been meaning to do an early oil change after the heads anyways. good time to switch.

 

Not sure what that is, but I am thinking exhaust anything that goes away that quick cold is not generally oil reacted.

 

I appreciate the reassurance. I do plan to install a standalone oil gauge later this year, but I think you must be right if the only thing that changed was exhaust related components and my mechanic said he didn't see anything else amiss while poking around with the heads/valley gasket off. I do need to adjust my y-pipe to muffler coupling, and that seems the most obvious place. no misfires, codes, lights, pending codes, or anything else and she idles as smooth as she ever has at 650-675 when warm. no misses or issues while driving, and I would think most oil, bearing, or rod issues issues would be much louder when revving more or under load.

 

Have you checked your trans fluid level lately?

 

I have not, but it has never leaked from anywhere. I just remove the fill plug to check, correct? it should be level with the fill plug on level ground?

 

It has to be running, when checking trans fluid.

Or you will lose about three quarters.