pcv valve

[Not Now]

My new to me 78 bronco has 2 pcv valves, one on each valve cover. Is this normal.

Any help

Don

 

[Broncobill78]

My new to me 78 bronco has 2 pcv valves, one on each valve cover. Is this normal.
Any help

Don

Don,

It's not factory but sure I've seen it. Do you have stock valve covers or aftermarket ? Stockers don't usually have it but I've seen aftermarket covers with a breather port in each cover and some folks like to stick a pcv valve in there. no real harm in it

 

[jbdkz]

My new to me 78 bronco has 2 pcv valves, one on each valve cover. Is this normal.
Any help

Don

Hmm, my 78 Bronco with a 351M engine only has a pcv valve connected to the valve cover closest to the drivers side. Do you have a 351M or 400 engine?

 

[Not Now]

Hmm, my 78 Bronco with a 351M engine only has a pcv valve connected to the valve cover closest to the drivers side. Do you have a 351M or 400 engine?

Thanks, I have a 351M. One is at one end toward the firewall and the other is like you said, front of the valve cover.

This may of been a ad one for better breather like some have said.

Thanks Don

 

[Broncobill78]

Thanks, I have a 351M. One is at one end toward the firewall and the other is like you said, front of the valve cover.This may of been a ad one for better breather like some have said.

Thanks Don

It really doesn't matter *what* engine you have, none of them came with dual PCV's. There are any number of reasons a previous owner would have installed the second valve. If the crankcase was being pressurized for some reason & oil was leaking out the top of the dipstick tube or blowing out gaskets then doing this would have made sense. Do you have aftermarket valve covers ? If you do then it could very well have been done for purely cosmetic reasons, maybe the guy's sense of symmetry drove him to do it. Might be something simple like who-ever bought & installed the valve covers saw a knock-out or a boss for the PCV on both valve covers (some companies do that to give you more flexibility as far as where you want the valve to be) and either thought he was *supposed* to install one in both or he figured it was a performance upgrade.

If you have stock valve covers I'd lean more towards it having been done to try & correct (or mask) a problem with a pressurized crankcase but if you don't have any current leaks then I wouldn't worry too much about it. You can drive yourself to drink trying to figure out why a previous owner did something inexplicable but the bottom line on for *this* particular problem is really that it's a non-issue. You have better ventilation than most and it won't cause any problems. Being aware of it is good though so you can keep an eye out for anything that might lead you to believe it was done to mask a problem & sell the truck (it's certainly been done before) but if it's running good and not leaking than I don't think you've got anything to worry about.