Mystery oil loss

[85MercPark]

My brothers 90s crown vic uses alot of oil. Not leaking and not really burning it. Tried PVC and hoses. About a quart in two weeks. Any ideas?

[p71towny]

No leaks???? Pop the breather cap off the valve cover and see if a lot of smoky oil comes out from blowby like a mofo.

[85MercPark]

Nothing that could account for the volume lost.

Pop the breather cap off the valve cover and see if a lot of smoky oil comes out from blowby like a mofo

What does it mean if this is the case? Bad rings?

[p71towny]

Yup, you can drive it like that but it fouls the plugs easy and will plug the cats after a while.

[85MercPark]

He hasn't said anything about the plugs fouling, will have to ask him

[Johnnyiroc]

rear seal? running onto torque converter, but somewhat held up by the converter hole plug, so it just slowly drips out? BTW a 90-91 CV is for the 5.0/5.8 boys. This thread may be better served there depending what year he has.

[Lincolnmania]

if it'snot leaking out onto the ground,replace the pcv screen.........might be clogged.........or the engine was overheated at one time and the oil control rings on the pistons are toast.........my towncar burned a qt every 400 miles like clockwork
scott

[93 Marquis]

If it's a 4.6 car, then the problem is valve seals. '91-'95 4.6 heads had a poor design that will cause oil usage over time. The amount of usage varies, but it will be seen in the form of blue smoke out of the tailpipe when the car takes off from a stop, or idles for long periods.

Ray

[85MercPark]

rear seal? running onto torque converter, but somewhat held up by the converter hole plug, so it just slowly drips out? BTW a 90-91 CV is for the 5.0/5.8 boys. This thread may be better served there depending what year he has.

It is a 4.6, It's a 90s CV, not sure of the exact year.

[85MercPark]

replace the pcv screen

Did that

oil control rings on the pistons are toast.........
my towncar burned a qt every 400 miles like clockwork
scott

exactly, that could be it.

[85MercPark]

If it's a 4.6 car, then the problem is valve seals. '91-'95 4.6 heads had a poor design that will cause oil usage over time. The amount of usage varies, but it will be seen in the form of blue smoke out of the tailpipe when the car takes off from a stop, or idles for long periods.

Ray

Or this, have to let him know to check that, those simple on the 4.6's?

[BigTomZ]

I second the valve seals. 92-95 model years have this problem. Those early (or pre-NPI) 4.6's are notorious for it. Not unlike Chevy's 305 from what I hear.

The valve seals are not a problem on 96+ 4.6's though, Ford used better valve seal material after that.

[85MercPark]

Thanks I will forward him your advise
:worship:

[93 Marquis]

On the difficulty scale I'd rate doing your own valve seals at a 8+. Getting the passenger side valve cover off alone is a battle.

Having it done at a shop will cost $600 & up, provided they want to touch it. As BigTomZ said, Ford addressed the problem in the '96-up heads. At the labor cost of the job you could pick up a newer low mileage 4.6 and replace it.

[85MercPark]

knowing my brother, he will drive it as is forever!

Thanks All