# Really dumb car question. **URL:** \ **Category:** Factual Questions\ **Created:** [April 12, 2014, 6:24pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950 "2014-04-12T18:24:51Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Kimballkid](https://avatars.discourse-cdn.com/v4/letter/k/b5a626/32.png) [@Kimballkid](https://boards.straightdope.com/u/Kimballkid)\ **Post date:** [April 12, 2014, 6:24pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/1 "2014-04-12T18:24:51Z")
Where is the PCV valve on a 1984 Buick Regal with the 3.8 2bbl engine (no turbo)? Is it in the passenger side valve cover at the end of the hose that goes to the crankcase breather? I’ve searched all over the internet and can’t find a site that shows the location, they just want to sell me one. Thanks!! ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [April 12, 2014, 7:02pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/2 "2014-04-12T19:02:05Z")
> [@Kimballkid](#): > > Where is the PCV valve on a 1984 Buick Regal with the 3.8 2bbl engine (no turbo)? Is it in the passenger side valve cover at the end of the hose that goes to the crankcase breather? I’ve searched all over the internet and can’t find a site that shows the location, they just want to sell me one. > > Thanks!! Did you already buy the new one. Sometimes the easiest thing to do is buy the new part and then look around the engine bay for the thing that looks like it. Is there a tube that goes from the valve cover to the air cleaner? ---
**Author:** ![Kimballkid](https://avatars.discourse-cdn.com/v4/letter/k/b5a626/32.png) [@Kimballkid](https://boards.straightdope.com/u/Kimballkid)\ **Post date:** [April 12, 2014, 7:04pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/3 "2014-04-12T19:04:01Z")
There’s a hose that goes from the valve cover to the crankcase breather which is on the side of the air cleaner. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [April 12, 2014, 7:08pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/4 "2014-04-12T19:08:12Z")
> [@Kimballkid](#): > > There’s a hose that goes from the valve cover to the crankcase breather which is on the side of the air cleaner. Pull the hose off where it connects to the valve cover. The rattling\* thing still connected to the valve cover (or the hose, whichever end it sticks to) is the PCV valve. On a car this old, you’re not going to hurt anything pulling on that hose. If that’s not it, just reconnect it. On the cars I’ve worked on, the PCV hose isn’t even on with a clamp, it’s just pushed on. \*If it’s old/dirty it won’t be rattling, but the new one will be. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [April 12, 2014, 7:33pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/5 "2014-04-12T19:33:47Z")
There will be two hoses, a breather that lets fresh air in and then the one with the PCV valve that vents it into the intake manifold. I think this car has the breather on one valve cover and the PCV valve on the other. I had this same engine in a somewhat newer front wheel drive car and recall being annoyed that they stuck the PCV on the back valve cover so it was a total pain in the ass to get to. So I think that would translate to being on the passenger side, assuming they didn’t change it between the FWD FI’ed version and the RWD carbed one. Just to add to what **Joey P** said, there’s an excellent chance that the valve will be stuck to the grommet and so when you pull the hose off, the PCV valve may stay in the valve cover and you may need to pull it out with some pliers. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [April 12, 2014, 7:45pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/6 "2014-04-12T19:45:01Z")
Oh, reading comprehension failure. Yeah, the hose that goes from the valve cover to the air cleaner is the wrong hose, so if that’s on the passenger side the PCV valve may be on the driver’s side. The PCV valve needs vacuum to function, so it’ll run to the intake manifold. On some cars the valve itself is on the intake manifold end, but with most GM’s it’s in the valve cover. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [April 12, 2014, 7:55pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/7 "2014-04-12T19:55:50Z")
> [@GreasyJack](#): > > Oh, reading comprehension failure. Yeah, the hose that goes from the valve cover to the air cleaner is the wrong hose, so if that’s on the passenger side the PCV valve may be on the driver’s side. The PCV valve needs vacuum to function, so it’ll run to the intake manifold. On some cars the valve itself is on the intake manifold end, but with most GM’s it’s in the valve cover. It’s been so long since I’ve replaced one, is that how that worked? One hose from the air cleaner to the valve cover (to bring fresh air in) and one hose from the valve cover, through the PCV valve, to the intake to burn blow by gases? Wow, I only vaguely remember that. But like I said, the OP can pull the hoses off (one at a time) and really not hurt anything. I’m guessing there’s not clamps on them and they’ll just pop right back on. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [April 12, 2014, 9:04pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/8 "2014-04-12T21:04:12Z")
Perhaps I can clarify a little more (maybe without boring you:smack:). Every cylinder continuously runs through a lot of fuel-air mixture, burning it and puffing it out the exhaust pipe. Well, most of it goes out the exhaust pipe. A little of it sneaks past the piston rings into the crankcase, every time the piston cycles, even in a healthy engine. A hose goes from the valve cover (positive pressure) up to the air cleaner (negative pressure), where it gets sucked back into the cylinders, to get burned. The **P** ositive **C** rankcase **V** entilation valve is a safety check valve. Fumes can go up into the air cleaner, but not the other way. There’s a few bad reasons why a flame might flash back into the air cleaner. When the PCV valve is working, that’s as far as it gets. When the valve goes bad, there’s a chance for the flame to go into the crankcase. That’s a very bad thing to happen. I’ve spoken simply, because the OP is a **Really dumb question.** If I made factual errors, please enlighten us. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [April 12, 2014, 9:57pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/9 "2014-04-12T21:57:21Z")
> [@Joey\_P](#): > > On a car this old, you’re not going to hurt anything pulling on that hose. Except maybe the hose itself or the PCV valve grommet in the valve cover, if the rubber has become hard. These parts can become brittle and crack or break. Parts stores sell the grommets (cheap) and should be able to help with the hose if needed. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [April 12, 2014, 10:07pm UTC](https://boards.straightdope.com/t/really-dumb-car-question/685950/10 "2014-04-12T22:07:56Z")
> [@AskNott](#): > > Perhaps I can clarify a little more (maybe without boring you:smack:). Every cylinder continuously runs through a lot of fuel-air mixture, burning it and puffing it out the exhaust pipe. > > Well, most of it goes out the exhaust pipe. A little of it sneaks past the piston rings into the crankcase, every time the piston cycles, even in a healthy engine. A hose goes from the valve cover (positive pressure) up to the air cleaner (negative pressure), where it gets sucked back into the cylinders, to get burned. > > The **P** ositive **C** rankcase **V** entilation valve is a safety check valve. Fumes can go up into the air cleaner, but not the other way. > > There’s a few bad reasons why a flame might flash back into the air cleaner. When the PCV valve is working, that’s as far as it gets. When the valve goes bad, there’s a chance for the flame to go into the crankcase. That’s a very bad thing to happen. > > I’ve spoken simply, because the OP is a **Really dumb question.** If I made factual errors, please enlighten us. That’s close but not quite right. Firstly, like I mentioned, the PCV hose goes into the intake manifold not the air cleaner. Secondly, although the PCV valve does act as a check valve in case of a backfire, that’s only a bit of a fringe benefit. Its main job is that it controls the amount of flow between the crankcase and the intake. When the engine is idling, there’s very high vacuum but little blow-by, so the valve mostly closes. Under acceleration, there’s lots of blow-by but little vacuum so the valve opens wider and eventually all the way near WOT. If the valve weren’t there and there were just a straight connection between the intake and the crankcase, oil spray would get sucked into the intake and a suction could form in the crankcase which could cause oil to get pulled past the rings and seals. That’s what the “positive” in PCV means-- it keeps the pressure in the crankcase positive preventing a vacuum from forming. Additionally, on carbureted cars, the air that flowed through the breather and PCV bypassed the carburetor, so the flow had to be consistent to prevent the mixture from going lean…