350 V8 valve stem seals leaking

robert graham

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My 1996 Roadmaster 350 V8 with 230,000 miles runs really great, but seems to be slightly oil-fouling spark plugs, mostly just on one side of each plug....guess the side facing the intake port?....Would Lucas Oil Stop Leak help swell/soften these seals? The car only uses about a pint of oil in 1000 miles of interstate highway driving and there is no obvious smoking from the exhaust....Removing to clean/replace these spark plugs is a PIA job and I'm doing it about every 2 or 3 thousand miles just to avoid fouling a plug to the extent that motor skipping might occur.....Any thoughts on this Lucas stuff in the oil?
 

alldodge

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Not a fan of mechanic oil in a can (so to speak), I would suggest removing the vlave covers and have a look at the valve stem seals. My guess is if they are intact then you need a rebuild, if they are hard and slide easy (up/down) then need them replaced (easy fix)
 

dwco5051

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Sep 14, 2008
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Also check the oil return passages in the head while you have the covers off. If they are gunked up excess oil will pool up around the valve stems. Have seen that problem a few times in those motors.
 

bigdee

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Jul 27, 2006
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Easy and cheap to replace. Use compressed air to hold valves up,compress spring,remove keepers and spring. Slide off old seal and slide on new seal. 2 hours labor.
 

Scott Danforth

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what bigdee said...... about a 2 hour job, 3 if you have a beer between heads.

most SBC's need it long before 230k on the clock

remove both valve covers
remove rockers
use a socket with a ball peen and tap each valve spring retainer down to loosen the keepers
remove the plugs
start with cylinder 1, install whip from compression tester and pressurize cylinder (motor will turn)
use spring compressor to remove springs
pull seal and replace
reinstall springs
move to next cylinder and repeat

reinstall rockers
reinstall valve covers
reinstall plugs

go driving
 

jimmbo

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May 24, 2004
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The access to 2 or 3 of the spark plugs in that car is a real PITA, I own 2 Roadmasters, a 94 and 95, and also a 95 Fleetwood, and there is very little on that engine that is easy to service/change.They are small cars
 

robert graham

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Yep, those 2 right(starboard) front plugs are pretty well buried....but I can get to them now after a couple of times. You don't actually see those plugs but you know they're there and where to put the socket....I put a quart of Lucas Oil Stop Leak in the motor and I'll pull the boat to Florida and back(1000 miles), then check oil consumption and spark plugs for carbon....then I'll see what to do next. The car runs like a dream but has 236,000 miles.....I can get a fresh engine installed for $5000.....or give it up and just buy a nice truck...I have the money but I just hate giving it up....
 

alldodge

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At least old cars can be worked on without a computer :rolleyes:
 

dolluper

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Jul 19, 2004
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Next oil change replace 1 quart of oil with quart of trannie fulid plus add half 500 ml of brake fulid that's my homemade lucas. 2 oil changes no difference pull vavle covers. Also check for throttle body gasket leak on those engines they are prone for that. Also dissy
 

Grub54891

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Jun 17, 2012
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You would do well to have a valve spring compressor like this.
555-80531.jpg
 

robert graham

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After adding the Lucas Oil Stop Leak and driving 2000 miles I removed the spark plugs and the carbon fouling is greatly reduced....like 90% better....so I'll keep using the Lucas from now on and my leaking valve stem seal problem is no longer a big deal. I'll keep checking my plugs every 5 or 10 thousand miles, sandblast them clean and good to go!
 
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