2004 4runner 4.0 100k miles
it knocks for about 4 seconds when its first is started up has anyone had similar issues?
I am the original owner and have religiously done maintenance
castrol synthetic since it had 30 miles on it
other sites say intake cam gear is leaking oil back into the pan?
experience and advice are appreciated
thanks

Is it a loud knock? I had a loud knock coming from my engine and it lasted two days before it blew up. What let loose was the rod baring and it ended up blowing a hole in the side of the engine block. At first it would just knock as the engine warmed up but after the engine became warm it would stop.

Are you sure it's a knock and not a misfire?
How long has it been happening and was it a sudden change or a slow onset?

Pre-06 V6s are known to (semi-rarely) blow the head gasket, causing coolant to leak into the (usually) #6 cylinder. The common symptom is rough running and misfiring for several seconds after a cold startup as the #6 cyl burns off/purges whatever coolant has leaked into it overnight.
If you think that could be the problem, pull the spark plugs and see if #6 matches the rest or has noticeably more contaminants on it.

It could be the head gasket I'm sure there's an issue with #6
I didn't think about the misfire. I recognized a issue before with it blowing smoke once and a while on cold start. i keep a pretty close eye on it and have no really noticeable missing fluid.
the knock is noticeable to me but im ocd it last no longer than 4 seconds and throughs no check engine lights

I have the same symptom, seems to be valves sound, noise disappears after 4 seconds.

did you ever figure out what the problem was? I have a 4.0 240K. Just had the head gasket, timing chain, head resurface, valve job done. Notice this tick on start up and goes away after warm.

my engine is brand spanking new, has a good 3k miles on it right now, its common on start up to hear it for a second or two. 1grfe is a loud freakin engine so its hard to tell sometimes, but makes sense to hear it on cold start up as all the oil has drained down by the time it cools off.

I followed your engine replacement project and it was well done. What oil and filter are you running?

Mobil 1 with Toyota oem filter
When I went to my dealer they were only like $5 or $6 cheaper than expected. Read somewhere that some filters cause pressure problems so for the price why even bother a different brand oem.

Thanks for the quick response! Congrats on the new motor. Does it sound like this?

1G-FE - Cold Start - YouTube

I've been not thrilled with Toyota filter anti-drainback valve performance over the past ~90K miles worth of oil changes, in a few cases they leaked down badly enough to cause rattling (#2 timing chain tensioners?) on initial startup. Each time when I removed the filter after sitting overnight, it was pretty much empty of oil.

Mobil-1 5W-30 made valvetrain ticking noise on my Tacoma and previous Tundra. I initially ran Mobil-1 High Mileage on this truck but it ticked noticeably.

Best results for quietness I've had lately have been a Fram XG3614 oil filter and either Shell Rotella Gas Truck (hard to find now), Mobil-1 0W-40 "European Car Formula", or Valvoline Synthetic High Mileage. I have a bigger XG3600 filter to go on next oil change, and a jug of Valvoline Extended Protection oil.

So basically I've been working two problems over the years:

1) oil filter drainback with Toyota filters, low frequency but annoying when it happens;
2) valvetrain tick at idle with certain oils...the engine currently has 270K miles on it so I can't really blame the oil, some oils just make it run quietly.

Valves don't sound like that. I hope that clanging is coming from outside the engine. If not, then drain the oil, filter it, and check for sparkly bits.

I put some mechanic stethoscope to it and it sounds like it's coming from the fuel lines and not the head. Might be the fuel pulse damper people have mentioned before. I'll try switching that out and report back.

replaced the damper and still hear the noise. Going to lift it this week and look for noises and exhaust leaks underneath. I do have a P0430 error code so it may be a manifold/cat leak. I put a stethoscope on the manifold and didn't hear it initially.

Turned out to be the top driver side idler pulley. Sound went away with new one.