(Advice) PCV Valve strange issue.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
So I have an 1983 Chevy C10 I bought from my grandpa.

QUICK READ IN BOLD

This recently started happening but the thing started vaping. I had to send it to its room and stuff and ground it for 3 months.

My oil pressure would drop when I ran the engine. I would take, wipe, and check my dipstick and almost all the oil was gone so I was thinking it was a head gasket leak. Right as I was ready to take apart the engine starting with valve cover I took out the PCV valve first. It was clean, still raddled, but when I took the tube off oil leaked all over. It had been drinking my oil straight from my PCV valve like a straw.

The look of the PCV valve was good. It Isn't rusty, isn't damaged. It raddles but it's allowing the engine to suck oil into my carbuerator. Should I replace it?
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
1,795
Reaction score
2,488
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
Gat an AC Delco or GM PCV. Have seen that many times. Rattling PCV will not flow as designed either.

A replacement PCV will not fix the oil use. Is the baffle in place? Excessive blow by?
 

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
1. What is a baffle.
2. I'm not sure how to test excessive blow by.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,595
Reaction score
6,941
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
1. What is a baffle.
2. I'm not sure how to test excessive blow by.
The valve cover on the left,bottom 1/3 of the valve cover. That is a baffle,it's kind of like a sheet metal box below the pcv valve. It is not air tight but it prevents the pcv valve from having completely unrestricted access to the crankcase vapors and oil splash. Blow by is too open to the viewers discretion, it's the amount of pressure that blows by the rings and if you've got the oil cap off you can see how much it's venting. But if you don't know what normal looks like you won't know what excessive looks like. Run a compression test. How low on oil does it get? In how many miles?
 

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
Oh yeah. The Baffle is there. I didn't know what you meant lol. I ran the truck with the vacuum tube from the Carb > PCV off and plugged the carb with my finger (to stop vacuum leak while running). Nothing comes out of PCV it's only when it's got suction from the carbuerator that it sucks oil real bad. Like to the point where if I take the Vacuum tube off the PCV valve after a run oil drains out of the Tube. I have an edelbrock 1406.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,595
Reaction score
6,941
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Oh yeah. The Baffle is there. I didn't know what you meant lol. I ran the truck with the vacuum tube from the Carb > PCV off and plugged the carb with my finger (to stop vacuum leak while running). Nothing comes out of PCV it's only when it's got suction from the carbuerator that it sucks oil real bad. Like to the point where if I take the Vacuum tube off the PCV valve after a run oil drains out of the Tube. I have an edelbrock 1406.
Change the PCV valve,but somethings not right you shouldn't have that much oil vapor in a very short time. The PCV valve doesn't touch the oil only the vapor that gets past the baffle. That's why I asked how low does it get,in how many miles. Also still run compression check so we can get an idea what kind of shape the rings are in.
 

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
I ran it about 10 minutes or so. I think what I was looking at was the hole the PCV goes in. Is that the baffle? If your talking about something in the valve cover I'll have to take it off tomorrow and check. I'll need to rent a compression tester unless i got one.

Honestly. Could I just use a flashlight to look down in there. Wouldn't I just see the valves If I didn't have one lol
 
Last edited:

Old Guy Bill

Full Access Member
Joined
Sep 10, 2023
Posts
319
Reaction score
922
Location
KY
First Name
Bill
Truck Year
1978
Truck Model
K20
Engine Size
400
What kind of valve covers are these? Are they the stock equipment?
The other valve cover, the one without the PCV valve, must have an opening for air to enter the engine….
Give us some pics!!
 

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
I replaced the PCV valve and it stopped drinking oil from the PCV. I did had a baffle, but for some reason the other one was just having enough suction to suck oil up. Nothing was replaced on this truck since 1983. It was not taken care of very well. I still have the ongoing issue of coolant and oil leaking in to the combustion chamber once the engine heats up, because my gaskets are MUSH. But besides that, at least it wont be ruining the carburetor I got!

Yeah, now it doesn't drink oil on startup, it just drinks oil when it's heated up because of the bad gaskets (im replacing soon). Which I prefer a lot more. I still haven't ran a compression test since I need to find one.
 
Last edited:

JBswth

Full Access Member
Joined
Jan 24, 2022
Posts
179
Reaction score
143
Location
Vallejo, California
First Name
James
Truck Year
1973
Truck Model
C25
Engine Size
292 cubic inches
I replaced the PCV valve and it stopped drinking oil from the PCV. I did had a baffle, but for some reason the other one was just having enough suction to suck oil up. Nothing was replaced on this truck since 1983. It was not taken care of very well. I still have the ongoing issue of coolant and oil leaking in to the combustion chamber once the engine heats up, because my gaskets are MUSH. But besides that, at least it wont be ruining the carburetor I got!

Yeah, now it doesn't drink oil on startup, it just drinks oil when it's heated up because of the bad gaskets (im replacing soon). Which I prefer a lot more. I still haven't ran a compression test since I need to find one.
Better replace those head gaskets right away. Coolant in the engine oil is bad, as when hot, it leaves a gritty residue in the oil and causes bad wear, as it is an abrasive.

J. B.
 

Laqota

Junior Member
Joined
Apr 16, 2024
Posts
7
Reaction score
1
Location
Joplin
First Name
Jerame
Truck Year
1983
Truck Model
C10
Engine Size
305
Better replace those head gaskets right away. Coolant in the engine oil is bad, as when hot, it leaves a gritty residue in the oil and causes bad wear, as it is an abrasive.

J. B.
The weird thing is I'm getting coolant blowing out of the side of my block on the passenger side, and coolant in my combustion (since the exhaust smells sweet, and is blowing white smoke). But currently, my engine oil still has not been affected. I was thinking it was my intake gasket (believe it or not. Was redone about 4 years ago), but I was just thinking of replacing them both (for my truck, it's about $64) since the truck is so old, and my grandpa used it since 2009, bought it from a guys forest, and drove it for work (painting in the MO area)
 

Latest posts

Forum statistics

Threads
42,974
Posts
925,836
Members
34,537
Latest member
Wyatt78
Top