Hi, I am new here, and new to my 92 F350 with the MPI 460. Problem is the repeated loss of 3 qts of oil in 275 miles. No leaks, and no smoke. Dealer says faulty PCV valve. One on the passenger valve cover works fine. Parts counter handed me a metal screw in PCV that I suspect goes in the manifold somewhere, but can't find where. Is there a PCV inside the manifold directly to the crankcase? Dealer said to make sure the passageway in the "manifold" was clear as well, which leads me to think it is inside or very well hidden. Truck runs great and only has 72K on the clock. Can a faulty PCV really eat this much oil?

Thanks,

TGT

 

Yes, a PVC can cause oil consumption. Under high manaifold vacuum conditions, the pvc valve should close. If it doesn't, it can suck oil thru it into the engine.

Now, does it suck as much oil as you are 'using' is a problem you will have to determine.

I don't know of nor have ever heard of an internal pcv valve. The pcv valve should fit in the grommet in the valve cover and connect to the manifold via an adapter plate below the carb or via a port/tube in the carb. If there is an internal one, you will have to get the dealer to show you the pic on his computer. He should be able to print out the drawing/pic for you.

Another area where oil can be consumed is by the vavles seals. Have you check or replaced them? What about doing a compression test/leakdown test for your rings?

 

If you used 3qts in 275 miles whether it be the pcv,rings,valve seals,etc. you would see smoke trust me. You sure its not leaking or you just dont see the smoke.

 

[updated:LAST EDITED ON 14-Jun-02 AT 04:06 AM (EST)]gray79, I would have agreed with you a couple of years ago. My son and I just replaced the 400 in our 82 F-250 4x4 that got to where it used a quart of oil every 100 miles and that engine "did not smoke" at all except a little at start up only. It "did not leak" at all, we hung out the window more times than I could count, while stomping the go pedal, followed it with another vehicle and totally ran the snot out it, trying to see smoke and there was none. It should have been a fogger but wasn't. As a matter of fact I would have felt much better about the situation it it was a fogger. The only sign of it, was a tail pipe that looked like it was on a diesel and foul smelling exhaust. That engine about made me nuts. We went through the heads completely (new guides and seals), it had good compression and vacuum, PCV system was fine. We just ran it till there was nothing left and swapped in a 460. It was missing and would not hardly pull itself and there was still no blue smoke. It had only around 85,000 miles on it when it started this. Believe if you want, but we have plenty of back up on this that left a lot of head scratching going on.

 

[updated:LAST EDITED ON 14-Jun-02 AT 04:46 AM (EST)]it sure is a head scratcher heck at least you got the 460 now great isnt it. I just put mine in this weekend in place of the 351mutt still workin the bugs out. But at least now it gets up n goes. Now I can put my tires n lift on. Ive had almost new 38s sittin since febuary cuz the m was such a junk. Im gonna have to get some new engine swap pics in my gallery. One last thing the brand of cars I work on has a pcv problem with certain engines. For the heck of it unplug the pcv you know of and plug the line and see if it uses the oil still. The problem with our engines is the oil baffels get slugged and trap oil where the pcv can suck it out. Hope this helps

Good Luck Andy

 

gray79f250, Yes we like the 460. My son and I re-built the 460 completely this past winter. We did not think the 400 was going to make it till we got the 460 built . The great thing is the 460 has not used a drop of oil even while breaking it in. I used Sealed Power moly rings in it. Its got around 1300 miles on it now, and freeing up good. Fuel mileage has went from 7.5 to 10.8 mpg already. Its got 285x75x16's on it. (metric 33x12.00x16's) It will churn them with little effort . We have not got into it hard yet though.