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mean350
05-30-2007, 10:22 PM
could a fuel pump cause low oil pressure if tyhe diapghram broke and let fuel into the crank causing the oil to thin out. i read bout it happening on a v6 and i got a 307 v8. it has all the sdame symptons as the v6 too and i can smell fuel in the oil. thanks

DixiePlowboy
05-30-2007, 10:29 PM
The first thing I would suggest is changing the oil and seeing if pressure comes back up.

I had a '75 IH Scout II with a 304 in it that was running 10lbs. at idle, and a maximum of 20lbs. My problem was a Fram oil filter that had "collapsed". I put a Motorcraft filter on it and immediately my oil pressure went back to spec.

Stay away from orange Frams.

mean350
05-30-2007, 10:32 PM
yeah frams are junk. it was running bout 50lbs on throttle and bout 30-40 at idle. there is gfas in the oil too. how could that gegt in there anyways?

mean350
05-30-2007, 10:37 PM
by th way at idle the oil pressure is 0 and goes up to 10-15 lbs while on the throttle.

cr480r
05-30-2007, 10:53 PM
It seems to me that if you had a ruptured diaphram in your fuel pump that you would have a fuel delivery problem... I would first change the oil to see if your pressure come back... You may have excessive blowby due to worn rings... Or a leaking carb dripping fuel into the intake after shut-off... Do you run a pcv valve?

cr480r
05-30-2007, 10:55 PM
by th way at idle the oil pressure is 0 and goes up to 10-15 lbs while on the throttle.

I cannot see fuel in the oil causing such a drop in pressure... You must have other issues...

longbedGTs
05-31-2007, 02:12 PM
As the engine wears, bearing clearences increase causing lower oil pressure. Sounds like a rebuild might be in order, or atleast new bearings. You could try thicker oil as a temporary fix. Do you have a hard time starting it? Hows gas mileage? Spark plug color? Perhaps its flooding out after shutoff and the fuel is seeping past the rings.

mean350
05-31-2007, 04:49 PM
the engine runs and starts right up every time i want it to. i get decent gas milage for it being a truck w a v8 and 35 in tires. didnt chek plug color. it dont smoke or anything. i dont run a pcv valve either. should I?

cr480r
05-31-2007, 05:01 PM
i dont run a pcv valve either. should I?

I would think so. Alot of people think that the pcv system is "Smog" or "unnecessary clutter" under thier hood... It is there to help keep contaminants(unburned fuel) out of your oil...

longbedGTs
05-31-2007, 05:12 PM
Id replace it. It vents crankcase gasses. Without it, pressure in the engine builds up and will eventually cause oil leaks from blown out seals or gaskets.

mean350
05-31-2007, 09:16 PM
it has the breathers on the valve covers. i changed th oil and filter today and the oil pressure went to 60 while driving and about 50 at idle. i hope it does not goes south again. oh well i guess im gonna find out. thanks for the help guys.

cr480r
05-31-2007, 09:21 PM
If you decide to run the pcv system... just run one breather in the valve cover opposite of the pcv valve... Thats amazing that the contaminated oil made the pressure drops so much... You are very lucky that was the problem...

Dustin87R
05-31-2007, 10:02 PM
Those 307s are notorious for producing sludge if it happens again I'd pull the oil pan and make sure the strainer on the oil pump isn't blocked.

mean350
06-01-2007, 02:19 PM
when i get paid next friday im gonna put a new oil pan and gasket on it and maybe a rear seal. im just happy the contaminated oil was the problem.

79fordblake
06-23-2009, 09:34 PM
If its anything like an old Ford 351m/400 I wouldnt worry about. When they get alot of miles on them they have zero pressure at hot idle and a max of 20-25 going down road and last for another 60,000 miles or so. Your engine may be a different story though, im a Ford man so don't listen to me, lol.

Sorry for bringing up something so old but when I seen it I wanted to say something. I was bored.