: valve noise at startup



chevymudnut
11-01-07, 12:10 PM
my fater has a 99 deville 118000 miles runs great he is getting valve noise at startup it's alot worse at a cold startup lasts a couple mins
it seems to have a small lifter type tick most the time at idle
i am an experenced mechinic but have not dealed with the n* engine before
i have read that there is a oil pressure releif valve that gets pluged up but i understand the oil pump is on the crank
what i was wondering is that is the problem is there some kind of cleaner like maybe bg brand that might help without pulling the pump?
and a couple of times when he makes a fast ture the low oil pressure message and beeping sound has come on then right back off

Submariner409
11-01-07, 02:04 PM
A cold idle cam follower tick and oil warnings in a turn sound suspiciously like low oil level.

Have you checked the dipstick? That series of N* takes 7 1/2 quarts to near the top of the hashmarks.....check hot and don't overfill.

I believe the '99 and later calls for 5W-30, year-round.

Also, search the performance and Deville threads for info on doing a WOT (Wide Open Throttle) run in 1-2 in order to load the engine to its limit, remove piston creown deposits, and then coast down to free up any stuck piston rings.

Ranger
11-01-07, 02:51 PM
Yeah, that "lifter" ticking sounds a lot like "cold Carbon Rap" aka piston slap to me. The first time my '97 did it I swore it was lifters. A good dose of WOT cured it. Check the Technical Archives at the top left of this page.

codewize
11-03-07, 02:30 PM
Sub; I don't think they went to cam followers until 2000.

Submariner409
11-03-07, 02:47 PM
Roller cam followers.........An OHC uses either direct contact lash caps (unholy bitch to adjust) or the hydraulic equivalent of a "tappet", either flat (or roller, which is what went in in '00).

In the pic, the hydraulic adjuster is the tiny "tappet" and associated half-moon oil passage to the lower left of the cam lobe. The roller you see replaced a hardened slipper shoe. With a lash cap, the cam would directly contact the valve stem tip, with a replaceable hardened cap over the tip in order to provide adjustment by measuring the lash, removing the cam, and placing the proper thickness lash cap on the valve. PITA

Submariner409
11-03-07, 07:23 PM
Technically, the cute cocked hat thingy is a roller cam follower. The little tappet looking thingy is a hydraulic lash adjuster. Why a roller? Less friction so you ZDDP guys don't need to obsess. Why a hydraulic lash adjuster ? So there is never any gap between any of the moving parts, so no "ticky-ticky".