Foxbody PCV Valve Replacement

Positive Crankcase Valves

Malfunctioning PCV valves can cause poor engine performance, idle problems, and reduced fuel economy. Another reason to change your PCV valve is to check the crankcase filter hidden underneath it. These small filters can become clogged creating excessive crankcase pressures. As a result, abnormally high pressures can cause gaskets and seals to leak. A mysterious oil leak is what prompted me to replace my PCV valve.

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PCV Valve Location on 1989 Mustang 5.0

The PCV valve on Foxbody Mustangs is located in the lower intake behind the upper intake. It is a bit hard to reach. I found it easier to reach by leaning in from the front of the car. The hose leading to the PCV valve pops off with relative ease. The PCV valve itself sits in a rubber grommet and should pull right out. My rubber grommet pulled out and dropped down in the back of the engine compartment. It is a good idea to replace it anyway.

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The Crankcase Filter

The crankcase filter sits in the lower intake manifold directly under the PCV valve. I used a backyard mechanic trick to remove the filter. I poked a 4″ long screw into the filter and screwed it in a few turns. I was then easily able to pull the filter out. As you can see, the filter was completely clogged with gunk and oil.

Replacement Parts

PCV valves, grommets and crankcase filters can be purchased at local auto part stores or online. Complete PCV valve kits are available for $15 to $17 from the many online Mustang part supply houses.

After carefully comparing photos of the online parts kits and the parts available locally, I opted to purchase my parts locally. The PCV, valve grommet, and filter available online and at local parts stores all appear to be the same “store brand parts”. My local Ford dealer did not have the factory parts in stock. They said no dealer stocks them any longer. If I wanted them, they would have to order them from the warehouse. The factory parts are also a lot more expensive. The factory PCV valve alone was $12 at the Ford dealer.

Unfortunately, I had to drive to several different auto parts stores to collect all three parts. I found the PCV valve at my local Pep Boys Auto Parts for $2.49 plus tax. I tracked down the rubber grommet at O’Reilly Auto Parts at a cost of $2.49 plus tax. Finally, I was able to pick up the crankcase filter at Advance Auto Parts for $5.99 plus tax. The total cost for my parts as just under $12 plus gas traveling to three auto parts stores.

Parts Purchased Locally – $12 total

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Parts Available at Online Parts House – $16.99

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As you can see, the parts in the kits appear to be exactly the same as those available at local parts stores.

Parts Installation

I sprayed brake cleaner on a lint free towel and wiped the hole in the intake manifold clean. Then, I dropped the crankcase filter into the hole. The side with the 6 tabs folded over goes down.

Next, came the rubber grommet installation. The rubber grommet did not fit quite as tightly in the hole as I would have liked. I went and did some research online. Other people’s results seemed to be mixed. For some people the grommet fit tightly. For others the grommet fit a little to loose. To improvise, I cleaned the mounting surfaces on the intake manifold and the grommet with a little brake cleaner. I applied a small bead of red RTV sealant onto the flange of the grommet. I then carefully in stalled the grommet making sure it was fully seated. Per the sealant’s label, I let the sealant dry for 24 hours.

Finally, it was time to install the PCV valve. Since my application only needed to make use of the valve’s bottom fitting, I used the included plug to seal off the top port. This is when I remembered that the PCV hose has a molded 90 degree bend. The PCV valve also had a 90 degree port. Therefore, the hose would likely kink when installed. Again, I was forced to improvise. I ran the valve under hot water to soften the plastic fitting. I was then able to pull off the plastic fitting. Bingo! Now the valve was configured exactly like the factory part and the hose would not kink once installed.

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Even after running around to several parts stores I was able to save $4 or $5 by buying locally. The car runs very well with these parts. Since it has rained since the install was completed I haven’t driven the car. The filter was way beyond needing replaced. Time will tell if the oil leak stops. If I need these parts again I might order the kit from an online supply house to save myself some time and hassle. Links to all the parts are listed below.

I hope this helps make changing your Foxbody PCV valve a little easier. – Jim Abbett