Theory on so many leaky rear main seals

[Dr.Scientist]

This is probably dumb garbage, but hey its just a theory. Just about every 94-95 GT that I have encountered in my time has had a leaky rear main seal. I have had a lot of friends that had these cars, and only one that the rear main didn't leak. I was looking through the owners manual of the car the other day, and Ford says that you need to change that PCV screen (located at the back of the lower intake) every 30K miles. Well in this day and age, 30K miles comes a lot sooner than most people think. Even back in the 90's when these cars were still "new". And when I changed mine, the PCV filter screen was pretty well closed off due to being caked over time.

And thats not the only thing. My car has a leaky rear main just like all the other cars I've been around. But when I changed that PCV screen in the lower intake, it stopped leaking oil. I have been driving the car for many miles, and there is no oil in the driveway, and there is no oil loss on the dipstick reading. Hmm...

The guy with the boost thread blowing oil reminded me of this. Do yall think it is possible that all these rear main leaks are due to people's little PCV screens just finally getting too caked up to flow air, and then the pressure just gets a little too high and it ruins an already aging rear main seal? Cause of course the pressure is going to look for a way out. If it can get out through a small crack or something in the rear main, its going to do it.

 

[Addermk2]

we all KNOW that the reason the 5.0 gets so many leaks is because of the piss poor PCV system.

Not exactly breaking new ground here....

 

[Dr.Scientist]

Yeah. What's a good way to improve upon it? Just do like that one guy did and install breathers on both valve covers? Looks a little sloppy. Or is it really necessary to improve upon it if you're stock?

 

[Addermk2]

best way to improve it is to allow ventilation from BOTH valve covers, instead of just one side. My PCV system allows fresh air to the front of both covers, and draws out the rear of both.

 

[OnyxCobra]

I thought just adding breathers would more or less create a leak in the system

 

[Addermk2]

I thought just adding breathers would more or less create a leak in the system

It does, if you do not seal off the input and output side of the PCV system.

 

[OnyxCobra]

which is where?

 

[Addermk2]

where the hole in the intake tube, and the port on the intake manifold that goes to the PCV are.

 

[Dr.Scientist]

I thought just adding breathers would more or less create a leak in the system

It does, if you do not seal off the input and output side of the PCV system.

So basically, you need to "delete" the old PCV system, before you go adding a new one.

I'd also really like to see a pic of your PCV system. The way I understand it, you have two holes per valve cover?

 

[Steven]

Alot of the drag racers will run crank case evacuation systems on small block fords. Not unusual to see 30-40 horsepower in a situation where the motor has serious crank case pressure problems. All you do is take a old smog pump, rework the inner parts to make it a vacuum pump then run the correct brackets. I've messed with it on my old race car before.

 

[Addermk2]

I thought just adding breathers would more or less create a leak in the system

It does, if you do not seal off the input and output side of the PCV system.

So basically, you need to "delete" the old PCV system, before you go adding a new one.

I'd also really like to see a pic of your PCV system. The way I understand it, you have two holes per valve cover?

I never said that.

Onyx has a tendency to confuse things... He mentioned breathers. Adding breathers to the crankcase, without sealing off the PCV system, will create vac leaks.

My solution to the PCV system issues was to add a fresh air inlet on both valve covers, and a PCV source on the opposite end. This allows fresh air to be drawn across both heads equally, and allows pressure to be removed from each side at the same time.

 

[evilcw311]

^^^^^^^^^pics would be awesome!!!!!

 

[Addermk2]

Pics would be awesome... but im half a world away from my car right now.

 

[evilcw311]

i see says the blind man.................

 

[Dr.Scientist]

Maybe someone else might post up their PCV system mods

 

[Insayne]

Id love to see adders setup when he gets home.