I have a 1995 Ford F150 4x4 5.8L and noticed that on the bottom of the air intake box, below the filter, there is a small, about 4in x 1in, filter. It hooks onto a hose that runs out of the box and looks like it runs into the engine oil refill tube. Does anyone know what this is for?

Thanks
Bubba

 

That tube is not a oil refill tube. It goes from the little filter to the PCV valve in the top of the valve cover. The PCV valve allows exhaust gases that get by the piston rings and collect in the crankcase to escape. There will probaly be an oily mist on the little filter, that is normal. They used to vent the crankcases to atmosphere but because of emission laws they vent it to the intake and it goes back through the engine.

There should be a cap on top of one of your valve covers, that is where you fill the oil. It is probaly black plastic with a yellow oil can logo on it.

 

After just taking another look at it I'm positive it connects to where you fill the engine oil. The cap has the engine oil can on it and when you take the cap off you see a hole in the tube where the hose from the little filter runs to.

If it were to be the PCV Valve and the tube became disconnected while driving would that affect anything?

Thanks
Buba

 

There are only two things it could be. Either a line for a breather or the line for the PCV. Unfortunatly I only know fords from about 75'-83 and 97-03. I have never really done anything with the inbetween years. But your truck has to have a breather to let fresh air into the crankcase and the PCV valve to exahust the gases. So what your talking about must be the breather. I just reread your post. on a 95 the PCV must dump the gases directly into the intake.

You would want to keep it connected. It shouldn't cause any problems or codes, but since it is pulling fresh air into the crankcase it should pull it through the filters so its nice and clean.

Sorry about the confusion. For some reason when I saw 5.8 I automatically thought of the old engines.

 

The reason I'm asking is because yestrerday while driving I started to hear and feel like a grinding noise and when I lifted the hood I saw this was disconnected. Do you think this could have been the reason?

 

Are you sure the noise was from the engine? Did you notice if the the engine was running differently than normal? Did the noise change with engine RPM or did it change with vehicle speed? Did it still make the noise when you had stopped? The more info the better. Also I don't think that would cause a problem.

 

[quote=gch;237048]Are you sure the noise was from the engine? Did you notice if the the engine was running differently than normal? Did the noise change with engine RPM or did it change with vehicle speed? Did it still make the noise when you had stopped? The more info the better. Also I don't think that would cause a problem.[/quote

No I'm not sure the noise came from the engine. The noise was off and on but always stopped when the truck was stopped. It felt like it was right under my feet and I just had the tranny rebuilt on Wed. so I'm probably going to take it back to the transmission shop to have them check it.

 

Sounds like a good idea.