NOW WHAT DO I DO???
Thread Starter
|
Senior User
Joined: Mar 2010
Posts: 156
Likes: 0
From: fort bragg, North Carolin
NOW WHAT DO I DO???
ok so I got a 77 f250 with the original 460 motor and it runs awesome! no leaks or knocks or anything its got at least 200k miles. I changed the oil the other day and i put Mobile 1 full synthetic blend thinking this would be good for the old truck, now theres a oil leak! its small but Im worried about it so does anybody know where to start checking seals and what ones to check? im seriously starting to regret putting the synthetic blend in the motor ran fine before also do I have a big job on my hands now? thank you for any help/suggestions.
Postmaster
Joined: Dec 2008
Posts: 3,940
Likes: 8
From: Southern Oregon Coast
That's the thing with synthetics - if you have even the tiniest of leaks, the synthetic will find it... Synthetic oils have a "de-sludging" (cleaning) characteristic that can unseal leaks previously sealed by old oil buildup. I think it also has smaller molecules than a mineral oil does and can get into places the old oil can't...
I've seen it written in more than one place that, if you plan to run synthetic oil in an old engine, make sure all the leaks are sealed up first...
I run synthetics all the time - run it in my truck and don't have any problems - So far, all my gaskets are in good shape, though...
I've seen it written in more than one place that, if you plan to run synthetic oil in an old engine, make sure all the leaks are sealed up first...
I run synthetics all the time - run it in my truck and don't have any problems - So far, all my gaskets are in good shape, though...
Post Fiend
Joined: May 2009
Posts: 5,054
Likes: 0
From: HOUSTON, TX
personally I would not put the same oil back in just to stop a leak, because a leak is a leak whether it be slow or fast. it may have been leaking before but with a thicker oil just did not fall as fast.
But as far as where to check (oil pan gasket, valve covers, rear and front seals, you didn't just happen to spill some when you filled it did ya. what about the oil plug, its not cross threaded when put back in or did you leave a gasket off the nut?
But as far as where to check (oil pan gasket, valve covers, rear and front seals, you didn't just happen to spill some when you filled it did ya. what about the oil plug, its not cross threaded when put back in or did you leave a gasket off the nut?
Post Fiend
Joined: Aug 2008
Posts: 6,751
Likes: 3
From: Sin City
2 places I'd check 1st. Oil plug, and the filter. My son changed the oil on my daughter's vehicle once, and the rubber gasket from the old filter stayed stuck to the block. Took awhile to figure that one out. 2 rubber gaskets are definitely not better than 1.
Thread Starter
|
Senior User
Joined: Mar 2010
Posts: 156
Likes: 0
From: fort bragg, North Carolin
thanks all for the help, now I wonder if I should run the synthetic for a few more days let it de-sludge the motor some and then put regular oil back in or is it true that once you use a synthetic in a motor you cant put regular back in??? The truck was sitting for months while I was deployed so Im sure all kinds of stuff settled
Postmaster
Joined: Dec 2008
Posts: 3,940
Likes: 8
From: Southern Oregon Coast
A "synthetic blend" is just regular oil mixed with synthetic... Shouldn't be a problem to switch back...
Trending Topics
Thread Starter
|
Senior User
Joined: Mar 2010
Posts: 156
Likes: 0
From: fort bragg, North Carolin
I just remembered another question I had, what should the oil pressure be for this truck? after I changed the oil put new plugs and electronic ignition the oil pressure gauge shot right up to around 80psi! now it fluctuates between 60 and 80+ psi depending on how I drive?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Posting Guru
Joined: Jan 2005
Posts: 1,299
Likes: 2
From: The Vieux Ford, Kansas
That is really high for an old motor typically I have seen 50-60 driving and any where from 30-0 at idle out of my old motors. The one that idled at 0 ran great for years until I sold the truck so go figure. Rule of thumb is you need at least 10psi for ever 1000rpms.
-John
-John
Elder User
Joined: Mar 2010
Posts: 544
Likes: 2
I just remembered another question I had, what should the oil pressure be for this truck? after I changed the oil put new plugs and electronic ignition the oil pressure gauge shot right up to around 80psi! now it fluctuates between 60 and 80+ psi depending on how I drive?
There are a few nice things about them 'putered up trucks. Older ones are more fun tho.
Zombie Survivalist
Joined: Feb 2009
Posts: 14,809
Likes: 3
From: Rock Springs, WY, USA
pressure in my 76 is around 50 psi at idle. i figure its a good thing, if nothin else its keepin the thick stuff movin and the hard stuff lubricated... 
and yes, the synthetics break up the built up sludge and it can even be potentially harmful dependin on how much had built up. so i only run cheap "natural" oil in the old beasty.
and yes, the synthetics break up the built up sludge and it can even be potentially harmful dependin on how much had built up. so i only run cheap "natural" oil in the old beasty.
Elder User
Joined: Mar 2010
Posts: 544
Likes: 2
What I've heard from more than one source is stick with what's in it. If it started syn, stay syn, cause it IS a better oil, but if you've been runnin reg for quite some time, stay reg. I wired a garage/apt for a guy who does mechanic work, and he was sayin he pulled apart a car that had been runnin syn from the get-go, and when he pulled it apart, all the parts were still shiny. None of the black/brown gunky buildup you normally see on the inside of a car with 100k+. He was a convert. I've also been told that syn doesn't have the corrosive leftovers from burning that reg has, which is the gunk and glazing that builds up on the internals.
I'm hopin' to find a block and do a ground up build up over time, and I'm planning on runnin' syn in it from the get go. I've read that since it lubes so well, it takes longer to break in the motor, cause the pistons don't form to the walls as fast as they do with reg. That's why some guys recommend running reg oil for the first 8-10k.
I'm hopin' to find a block and do a ground up build up over time, and I'm planning on runnin' syn in it from the get go. I've read that since it lubes so well, it takes longer to break in the motor, cause the pistons don't form to the walls as fast as they do with reg. That's why some guys recommend running reg oil for the first 8-10k.
