Knocking on cold mornings

My 01 DC 4cyl prerunner has had a knocking sound for the past four years. It only happens when its been parked for 12+ hours, and the temperature hits 40 or lower. I've taken it to several toyota dealers and no one can seem to find anything wrong with it.
The harder you press the gas the faster and louder the knocking gets. Sometimes it goes away in seconds sometimes minutes.
The truck still preforms flawlessly but the sound is terrible.

 

i had the same thing with my 2000 it did go away when it warm up

 

The knocking always goes away eventually its just that I DON'T want it to knock at all. It gets a little more noticable every year. I can't believe there isn't a solution.

 

You could always pre-heat the engine with an oil pan heater or block heater, not sure if it get rid of the problem entirely but it might mitigate the problem. 40 degrees isn't all that cold either.

 

Could also be worn timing chain guides

 

Ok now that gives me something to work with. Thanks man. I will give it a shot. Maybe thats the problem. Piston slap sounds like it too. How do you correct piston slap?

 

I have a 2002 4 cyl tacoma. my truck used to knock when i would first crank it up on cold mornings. i changed the oil to 10W 30 and it hasnt made the knocking noise since

 

Its just piston slap. The reason why the noise goes away after a little while is because once the pistons warm up and exapand, there is no longer enough room for them to bounce and slap around enough for them to make the noise.
I wouldnt worry about it.

 

Try some different kind of oil, like 10w30

 

think maybe a lifter?

 

Oil has nothing to do with it. If it were a rod knock or a lifter rattle, thicker oil might help, but thicker oil wont do a thing for piston slap.

 

yep chris, ur right, i wasnt thinking about that part!

 

10w 30 huh? all i can do is try. I'll give the mobile 1 a shot. I know its not really doing much damage because its gone on for so long. I just wish I didn't have to see the look on peoples faces when I crank it up and drive off.

 

could it be ur timing chain slapping the cover?

 

yea i know that feeling when everybody thinks your truck is messed up ha. i dont really know what causes it to knock like that. ive heard alot of different reasons but when i changed my oil in mine it doesnt knock anymore

 

I live in michigan and there are times when it gets like -20 outside the truck always starts up right away never had a problem with starting in cold weather. It starts better then my dads 1/2 ton chevy hehe. As far as knocking I get it all the time when I first start my truck in the winter its just something it does when it is cold but it goes away in 1 min or less not much you can do about it but it does not hurt anything as long as you let it warm up a bit and give the oil some time to get to the top end