Bigblock

Has anyone had this problem?I've tried changing the oil filter and oil.Oil is changed like clock work.No abuse.BTW it's a 04 taco 4WD.Toyota filter.It knocks (taps) for 5 or 10 seconds and then goes away.

DeathCougar

iTrader: (23)

Hook an oil pressure gauge up to it, to see what kind of pressure you are getting. I have seen many engines die because of sludge, and sludged up oil passages will reduce or block oil pressure.

Have you owned since new?

Bigblock

Good suggestion,but there's only 30K on the truck.

DeathCougar

iTrader: (23)

Well, it is possible that if you are not the original owner, and whoever owned it before you didn't change the oil...We have sold engines to Lexus dealers before for a guy with only 45k on his IS300 cause he never changed the oil and locked it up. Doesn't take long for sludge to develop, mind you.

Other than that, perhaps valves need adjusted? Since its DOHC engine, perhaps the valve shims could use some work. Not 100% sure tho, since everything I have owned has a Rocker Assy lol.

Also, check your exhaust manifold for a crack (under the head shield in the middle is the place they crack)....those 2.7 motors exhaust manifolds ALWAYS crack, and that could also be the tick.

Bigblock

I'll check that.

tom_mag

Is the oil light on when you hear the noise?

If the easy stuff doesn't solve the problem you may need to pull the valve cover and start it to see if oil is reaching the lifters, etc (really messy). Also if the oil hasn't been changed you will see dried oil caked onto the bottom of the valve cover.

Bigblock

I forgot to mention that it has to be very cold,20 or 30 degrees outside.Any warmer and no knock.

kenwoodrunner

Probably piston slap. the 2.7 is known for it on cold start. when i was looking all the 2.7's that i started cold did it. try yahooing 2.7l toyota piston slap. although toyota denies it. it is a well known issue thanks to the internet.

Bigblock

Either exhaust or piston slap,it hurts nothing.Am I correct?

kenwoodrunner

correct it doesn't hurt anything. it is usually associated with corporate penny pinching on using to short piston skirts. once they get warm the problem goes away. the 4.7 in the 4runner and other trucks are reported to do it also.

tom_mag

What weight oil are you using? If its that cold outside I would use 0W-30 or 5W-30 and nothing thicker. Piston slap and noisy lifters are a sign of wear, but will not cause any serious damage if you don't fix it. I would imagine it is bad for the cylinders and pistons and would hurt emissions, but all that will be fixed if you rebuild the engine. Piston slap is from worn rings and cylinders that allow the piston to vibrate in the cyliner as it travels up and down. Lifter noise is usually from oiling problems or a worn or bad lifter. Once again, unless you plan on rebuilding the motor it won't hurt anything to just let it go.
If it is still under warrenty I would have the dealer look at it. It might have been put together with poor tolerances.

scheu

I have the same noise. Truck is a '00, 2.7. Had it since new. Now has 70K. Regular oil changes (every 3k). Mine only does it when it really cold and has been parked outside. i.e. winter time and leaving work at 2am. Someone once told me that it's the timing chain tensioner. That it's a poor design and Toyota won't do anything about it. No idea if that's true.
Scheu

TACOKRAWL

My '00 2.7 does that too. Only when really cold outside and for about 5-10 seconds after startup.