High pitch noise at start up!

I recently changed the oil in my 08 Tacoma 4X4 I4 and put in Valvoline Synpower (fully syntetic oil) and changed the grade from 5W-20 (which is what it calls out) to 5W-30, mostly in the hope of make is run quiter and provide better wear protection. But right after the oil change when I first started the truck and also again this morning couple of days afterwards (cold morning), I heard this high pitch squealing noise (not very loud) comming from the top of the engine block, apparently from the valves. I would hear this noise for about 15-20 seconds then as if something kikced in or kicked off the sound would suddenly stop and it would run quite and smooth again. it seemed as if the valves weren't getting much lubrication at first then it would adjust itself!

Has anybody experienced anything like this? Do you guys have any explanation for this. the thought that the valves not getting much oil at first (as I mensioned above) even though it might seem that way, doesn't make any sense since both 5W-20 and 5W-30 have the same viscosity and flow properties at cold start up.

I would greatly appreciate any insight you guys could provide.

 

I used a large funnel and did not spill any oil anywhere.

 

the oil filter on 4 cylinder engines is under the engine block and to the back. the only place you would spill any oil from replacing the oil filter is on your own hand and forearm. there is no belts close to it.

 

On some other forum I have read about people complaining about wierd noises at start up which attributed to oil filter not having a good anti drain valve (probably not using the proper name for it). but the idea was that drained the oil from the oil filter which caused "dry" start ups which made the noise. Has anybody heard anything about this or knows anything about this. But I have to say that explanation doesn't make much sense in my case, since the oil filer is positioned vertical with the opening facing up, so gravity should always keep it full of oil.

 

Toyota oil filter, which is what the individual complaining about this problem was also using on his Thundra truck.

 

Approximately 6 qts of oil, which is what it calls out. the oil level is just above the full line.