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