: PCV valve location 2003 Deville

06-18-04, 01:02 PM
Can anyone tell me precisely where the PCV valve is located on a 2003 DeVille Northstar 275HP regular engine? I can't find it. It was easy to find on my 99 Deville.

06-18-04, 02:07 PM
It's on the rear valve cover under the plenum cover. You won't recognize it. It looks like an orificed nipple.

Anthony Cipriano
06-18-04, 02:31 PM
There is no PCV valve on a 2003 Northstar to my knowlege. It was replaced by a simple orifice pressed into the cam cover fitting. The Onboard Diagnostics requirements change regularily and the PCV system came under the OBD mandate by EPA as an emission device that must be monitored by the onboard systems. So, the PCV "valve" per se was eliminated and replaced with the simple orifice. One less thing to go wrong, the onboard system is monitoring the PCV flow and operation so if it does go awry it will set a code and turn on the service engine light. Nothing to worry about with the PCV anymore. It'll even diagnose if the hose is off or leaking/cracked with age.

I don't recall exactly when but I think the PCV valve was eliminated on the 2001 model engines. Not sure but around then.

06-20-04, 08:29 PM
no pcv??? oh well, i wonder why not?:hmm:

Anthony Cipriano
06-20-04, 11:01 PM
no pcv??? oh well, i wonder why not?:hmm:

The engine still has a PCV (positive crankcase ventilation) system. It just doesn't have a PCV valve like the older systems did. The PCV valve is just an orifice anyway so "valve" was replaced with a fixed orifice. See the post above as for "why".

06-21-04, 12:48 AM
The engine still has a PCV (positive crankcase ventilation) system. It just doesn't have a PCV valve like the older systems did. The PCV valve is just an orifice anyway so "valve" was replaced with a fixed orifice. See the post above as for "why".
sorry...i feel like a dummy...so basically it is one less thing you have to worry about during a tune-up...if that is the case, that is nice. thanks for setting me strait.:cool:

11-21-07, 08:55 PM
Funny thing is you go to a auto zone or discount auto parts and they sale you a pcv valve for this year...I went crazy looking for it in my '03 deville...thanks guys.

11-22-07, 09:12 AM
The older "rattle" PCV valve was always open, just as the newer fixed orifice style. The old style had (maybe) a weak spring and tapered plug inside which was designed to slam shut if there was a backfire, preventing flame from potentially entering the valve cover/crankcase and igniting any oil vapor. The tapered plugs were of various sizes to meter airflow for differing engine sizes, and today's orifices are sized accordingly. The PCV flow at idle is actually calculated as part of the required idle airflow circuit.

While backfire is still possible, the lack of fuel vapor throughout the intake manifold has all but eliminated the possibility of igniting the oil vapor in the crankcase.

During a cleanup/tuneup, it is not a bad idea to run a doubled pipe cleaner through the orifice. Some pretty nasty stuff passes through it........

08-15-13, 07:16 PM
Well I'll be dipped. I find this extremely odd since there's a TSB stating that a clogged PCV valve can cause high oil consumption on these cars and even more odd that a part number CV769C is listed as the PCV valve for the 01 - 05 Northstar

I went to the dealer, got one for each car and low and behold the only thing in the cam cover is a wide open orvice as described in this thread. What the hell. So now the question is why the hell am I using 2 qts of oil every 1000 miles?

08-15-13, 09:05 PM
2 qts per 1000 miles has to be a mechanical failure of some sort (broken or stuck ring, bad valve seal).

Have you read the "River Runs Through It" thread?

08-15-13, 09:44 PM

08-16-13, 10:36 AM
There was absolutely no reason to start a poll on this question - even back in 2004 (OP). Please do not chew up server space with useless polls. Thanks, CF Staff.

As posted, ALL Northstars have a PCV (Positive Crankcase Ventilation) system - the "valve" depends on year and model. Some have the older "rattle valve" while others have a fixed orifice.

All one need do is to find the large line that leaves a valve cover and enters the intake manifold - that's the vacuum - dirty air - (valve/orifice) side. The other (supply) line comes from an atmospheric air feed on or near the throttlebody - after the air filter: The clean air side.

09-21-15, 03:25 PM
This is odd. All chain auto parts stores list and stock a pcv valve for the 2003 Seville with a Northstar. Even AC Delco's online parts catalog lists one through the 2004 model year. I purchased a new pcv valve for my mother-in-law's new acquisition, removed throttle body cover, located vacuum line, and disconnected it to find what looked like a pcv (silvery metal, in contrast to the black engine parts), but apparently pressed right in the valve cover(?) WITH NO RUBBER GROMMET! What's the deal? Any advice?

09-21-15, 03:48 PM
Yes............ the later (roller cam) engine has no PCV "valve" as such. It's a fixed orifice. No cleaning or replacement involved. 2001 might have the older rattle valve type - it changed in there somewhere. (My 2002 has a fixed orifice)

Please read the rest of this thread. You'll find that many parts sources incorrectly list many things for the 2000 - 2004 Northstar.