Cadillac Owners Forum banner

1 - 9 of 9 Posts

·
Registered
99 Seville (RIP), 12 CTS AWD
Joined
·
23 Posts
Discussion Starter #1
I want to replace the PCV Valve on my 99 seville. Can someone tell me where this is, and how to replace it? I have heard it is very easy, but havent seen any info on where and how.
 

·
Cadillac Technician
none
Joined
·
11,051 Posts
Should be sticking in the rear valve cover, usually near the front of the engine (right side of the car).
You just pull it out of the grommet, and the hose, stick in the new one and put it back in the grommet.
 

·
Registered
1999 White Diamond ETC
Joined
·
2,540 Posts
Is this a preventive maintenance item? I hear it's an inexpensive part. Would it benefit me to do it?
 

·
Cadillac Technician
none
Joined
·
11,051 Posts
It's a regular maintenance item, but it's not a critical one.
They rarely ever go bad.
 

·
Cadillac Owners Connoisseur
Joined
·
1,164 Posts
It's an extremely simple and inexpensive maintenance item. It costs about $2 and takes about 5 minutes to put it in with zero tools required. Probably a good investment.

A PCV valve is basically just a hollow tube with a weight in it that is attached to a spring. The weight and spring modulate the air flow through the valve, thereby ensuring that oil vapors and blowby gases in the crankcase are burned instead of being exhausted to the atmosphere where they can contribute to smog and other air quality issues. Air flow through the valve comes from the intake manifold vacuum, and supply air comes from some point after the air filter so that dirty air doesn't contaminate the oil. Without the PCV valve, there would be high vacuum in the crankcase and it could be hard to remove the oil dipstick while the engine was running. Because oil and blowby gases pass through the valve, it can get crudded up with that gunk and stick open or shut. The spring can become detached from the weight so the proper air flow is not moving through the valve. All sorts of weird symptoms can be tied to a PCV valve problem.
 

·
Super Moderator
2010 DTS
Joined
·
87,313 Posts
I think 99% of PCV valves are changed needlessly. Granted, I don't work on cars for a living, but I have yet to see a bad one. Shake it, if it rattles, it's good. If you really want to clean it, hold your finger on one end, spray some Gumout in it, place your thumb on the other end and shake. Then pour out the Gumout and replace it.
 

·
Registered
Joined
·
442 Posts
After my last oil change, I checked and the level was about 3/4 inch above the max fill line. When I complained to dealer about it, they said not to worry the excess oil would be blown out the PCV and get burned. Wife drove car 2 hours long trip before getting oil corrected, and I checked the level when she got back, it was at the max line. Is it really possible oil went out the PCV?
I found oil puddled on rear of engine down in the valley below heads.

1994 Seville STS

Can you be more specific about the PCV location, mine is more than likely a mess?

A photo would be great.

Coincidentally the engine started overheating afterwards.
 

·
Registered
94 Eldorado, and a 99 ETC
Joined
·
3,887 Posts
Rfishing, it's normal to have some oil down in the valley. I mean it's never been cleaned down ther in what? almost 12 years? I have some oil down in the valley of my 94 but I'm not worried. When it's daylight I'll take a picture of the PCV valve and inspect mine just because I haven't... ever...
 

·
Super Moderator
2010 DTS
Joined
·
87,313 Posts
rfishing said:
After my last oil change, I checked and the level was about 3/4 inch above the max fill line. When I complained to dealer about it, they said not to worry the excess oil would be blown out the PCV and get burned. Wife drove car 2 hours long trip before getting oil corrected, and I checked the level when she got back, it was at the max line. Is it really possible oil went out the PCV?
I found oil puddled on rear of engine down in the valley below heads.

1994 Seville STS

Can you be more specific about the PCV location, mine is more than likely a mess?

A photo would be great.


Coincidentally the engine started overheating afterwards.
Look on the rear cam cover (passenger side) can't miss it. The PCV takes crankcase gasses and routes them through the intake so it will always be oily when you pull it and look at it. If the crankcase is overfilled, the crankshaft counter weights will whip the oil into a mist and then be sucked through the PCV, into the intake and burned (normal). That is why it is said that topping off the crankcase to the max mark will only exasserbate the oil consumption issue.
 
1 - 9 of 9 Posts
Top