Cold start knock / ticking under load

[HJC]

Hey guys,

This is on a 2003 Toyota Tacoma with the 2.4L 2RZ-FE 4cyl and 99,150 miles on it. On a cold startup, the engine with knock or tick if I drive it. The noise would get louder the harder i press the gas.

If I let it warm up a minute or two before driving, there's no evidence of the noise.

My mechanic friend says it's the bottom end going out and that it's just a matter of time before the engine dies.

Any ideas on what it could be? I've read it could be worn bearings or piston slap. Should I trade it in before the truck dies and become totally worthless?

 

[Herz]

what weight oil are you using?

 

[HJC]

I've always used the required 5w30 as stated in the manual. Currently have Mobil Clean 5000. But it does this with Castrol GTX and some bulk oil from a repair shop too. The bulk oil was a 1 time thing because I hurt my hand.

 

[punisher]

I would lean towards piston slap from your description. Rod knocks generally get worse as the engine warms up/oil thins, conversely a piston slap quiets down as the engine warms up (veteran of forged pistons so I know).

 

[mechtech2]

Valve tick noise is not dependent on load.
Piston slap or bearings are. Maybe a chain tensioner.
But another possibility is the injectors. They can be quite loud, and are often mistaken for lifter noise. When cold, they are flowing more[for that RPM] and can make a lifter like noise.
At this point I would rule out the rod knock, and concentrate on piston slap or injector noise.

 

[HTSS_TR]

How do you fix/eliminate piston slap ? I think my '00 MB E430 has piston slap, it is more pronounce at operating temperature.

 

[Footpounds]

I visit a Tacoma board and this is a common issue. In fact, my 2.7L Tacoma (53,000 miles) does this when it starts getting cooler out. It seems the consensus opinion is that is the injectors. I seriously doubt your engine is going out. I have tried different oils and different oil filters and nothing seems to make a difference which lends credence to the injector theory. I personally don't worry about my "ticking".

 

[addyguy]

I also highly, highly doubt a toyota 4-cylinder is dying at 100k miles.

Sometimes, changing the filter you use (getting one with a good-quality ADBV) will fix the problem.

 

[Scdevon]

Originally Posted By: Footpounds
I visit a Tacoma board and this is a common issue. In fact, my 2.7L Tacoma (53,000 miles) does this when it starts getting cooler out. It seems the consensus opinion is that is the injectors.


2.7's are known piston slappers. If you can change the noise with engine load when its cold, then it's "the slap". Totally harmless. Toyotas run for hundreds of thousands of miles with cold piston slap.

I can't believe the number of people on the internet who actually believe that fuel injectors "knock" when cold. The moving parts in a fuel injector are no bigger than a sewing needle. They aren't capable of making knocking noises or even noises louder than a light tick akin to a loud pocket watch "tick" audible only with the hood open.

 

[panthermike]

My 2000 Corolla does the exact same thing. It's been doing it for the better part of 50K miles or so. I just try to let it sit for a minute or two before driving. If not, it goes away within a few minutes. I just keep driving it, 161K miles as of today. Burns 1qt/1000 miles but I love the car!

 

[OVERKILL]

Originally Posted By: HTSS_TR
How do you fix/eliminate piston slap ? I think my '00 MB E430 has piston slap, it is more pronounce at operating temperature.


You don't.

Slap gets quieter as the pistons heat and expand.... If yours gets louder, it isn't slap........

 

[HJC]

Great info here everyone. Thanks for the input. I'll conclude on piston slap and just keep on driving!

 

[mechtech2]

scdevon -
Injectors can make loud tick noises for sure.
More so when cold.
On some cars it is almost identical to a lifter tick.
Some systems are quite loud, even if there is nothing wrong.
I know this from empirical and vicarious sources in my career.
No doubt about it.

BTW, it does not matter what size they are - that is foolish reasoning.