Just thought of something that my mechanic told me when I took my truck in. The rocker arms are aluminum, go figure, but have a steel disc where they contact the push rods. That disc can over come loose and cause a tapping noise. It's not a major deal, the engine can run forever without it causing a problem but it is annoying to most owners. Pulling the valve cover is the only way to truly verify what the problem is.

 

if yall think it may be the oil leaveing the valvetrain why not try lucas oil stablizer . will cling to parts much more than reg oil. quiter startups ,better protection,slows any leaks,and its 100% petrolium base. i've used it for years

 

No matter what additives you use in an engine the oil is going to drain back in to the oil pan. It's gravity. I have to agree with Spike that if you feel it necessary to use any additives in your oil it's time to consider a different oil.

 

Mine tap like mad, but it still runs just fine like that for the past couple of years. I never did think to pull the valve cover while running and see which one it is, did not know you could do that. I may try that soon since a couple of ATF flushes has not cured the problem. I will try to tighten the rocker arms too and see what happens.

Good luck with yours.

 

mine is a D2 there is no pulling the valve covers while running, second i have put lucas in the sump with no luck, rite now there is 10-30and in the summer i may run 10-40 always royal purple, highest zddp out side of break in oil, ill try the trans flush but i think its highly unlikely i could have junk in that motor with the pampering its had. and again its only a noise that coem on when i drop the truck in gear, i wlked it up on a curb with the e0-brake in drive while i used the my steth, back top of motor is where it seemed most pronounced.

 

sorry to hi jack, i have an 03 dicsovery, did the atf flush yesterday put in 10-30 oil and the tapping noise still there, so should i tighten the rocker arm as suggested, is there any instructions here on how to take of the valvecovers on this trucks, i use to work on my subie but this truck is a totally different animal, any help is appreciated.
thanks

 

No dont just go and tighten the rocker arms.
Use 10w-40, since you just did a engine flush in 500 miles change the oil and filter again, this time use 10w-40.
Also with the engine off tap on your cats with a hammer and see if they rattle.

 

The rocker arm are set at a specific torque setting, over tightening them will do nothing break a bolt or damage the rocker shaft or arms.
So, because it is an 03, start with the basics, have a mechanic do 4 oil pressure tests, cols at idle and at 2000 RPM's and at operating temp at idle and at 2000 RPM's, then get back to us.
In the mean time, don't change your oil, 10W/30 won't be causing this in a healthy engine.

 

Disco Mike is right, these are rail type rocker arm setups. 4 bolts hold the entire side onto the head. I have had an issue with what seems to be described here. I rebuilt an entire engine and still had the same noise. I spoke to my machinist and he said that it most likely is a slight piston slap on the cylinder wall, as the engine heats up the piston expands and no more noise. I used my existing pistons and rods (rods were reworked), so thats the only explanation that we have been able to find. Currently the motor is pulled out, and going to get a complete double check of all the clearances at the machine shop. Lifters are not likely to be the problem if it sounds deep in the engine, also a collapsed lifter noise will not go away as it warms up. most of the time you can compare a lifter/rockerarm noise to hitting two large sockets together in the palm of your hand, take into consideration that noise will be muffeled when coming from your engine.

 

thanks for the reply and answers, but last night my wife used the truck to go to the grocery, and lo and behold, the truck wont start, it just clicks, i tried to jump no good, i have it towed to the mechanic this morning i think my starter went out, 3 lights stayed on oil, battery and the service engine light stays on, damn i think imight be way over my head on this truck, i jgot a great deal from a private sale but its only been 2 weeks and now i have to possibly put a starter on it.