i've got oil in my cylinders 4 5 and 6 on my 250. my plugs are fouling out and i can't drive more than 20 ft before the mav starts belching smoke and chugging to an embarassing stop, at which point she refuses to start again, until i've cleaned the fouled plugs and then we repeat. i don't think that three of my rings would go bad at once, so i'm trying to trouble shoot. i heard that a clogged PCV could force oil into your cylinders, but i'd never heard that before, so i'm not sure if theres any truth to it. i'm leaning toward bad valve guides. so here i am. one, i don't know where to FIND new guides. autozone, etc. told me they are "unavailable" and i haven't had a chance to call a more legitimate autopart store yet. the dealership is of course out of the question because they won't tell you if they have a part until you tell them what kind of car you have, and once they hear 'seventy four' the kid they have answering the phone refuses to help you. two, having never replaced valve guides before, i was wondering if anyone who had done it before had some tips or hints for me that a manual wouldn't cover. thanks, Jim
Valve guides are something that a machine shop needs to install. You might be thinking of valve seals which are little umbrella seals that push over the top of the valve stem. Because your fouling the last 3 cylinders, I'd pull the valve cover check to make sure the oil return drain hole in the back of the head is open. If the return hole is plugged then the valve cover can fill up with oil and go down the valve guides. Especially if the seals are gone.
Jim, I have been a ford technician for over 20 years and I havent seen an engine oil foul the plugs while its running to a point the engine cuts off.I'm not saying that it couldnt happen but are you sure its oil?I have seen some carb flooding concerns that seem to effect some cylinders more than others.Also raw fuel through the exhaust can be white smoke rather than black if its totally unburned.Was just a thought and I hope it is something that easy for you. Howard
Is the transmission an automatic? If so - pull the transmission vacuum modulator line off at the intake and see if there is tranny oil coming up. Could be a bad modulator diaphram. Been a long time since I worked on a 6 but isnt the vacuum port on the back side of the intake pulling mainly off 4,5, and 6? Cleaver
My #6 plug on my Mav was fouling pretty bad with oil and I put on a spark plug extender (about $2.00 a copy at Pep Boys) and that took care of it fouling out.
