Odd oil pressure issue
Thread Starter
|
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
Odd oil pressure issue
Hey all. I've got a '79 LTD with a 351w in it. It seems that I'm losing oil pressure when hot in gear at idle. This has been verified with a gauge. I have 65psi cold in park, and ~15 in gear after about five minutes of warm up time. I used some 5w30 (what I had, I live in the sticks) in it when it was low the last time. I noticed that I no longer get that annoying ENGINE light flicker. It was low again here recently so again I put 5w30 in it. First time out it did act like it was getting worse, but then just like before it's stopped almost completely.
Thread Starter
|
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
Running a Motorcraft FL1A filter, and whatever oil I can get for less than $2. Usually NAPA oil. As far as I know the engine has never been apart. It's got roughly 165k miles on it. Between the front seal, and the dipstick tube leaking at the pan, it's losing about a quart every week and a half to two weeks.
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
this is strange, usually the thicker oil will increase pressure and remove the knocking but yours is doing the opposite. You might try some seafoam or just continue to run the 5w oil. might do a compression test. how do the plugs look and is the pcv valve new?
Thread Starter
|
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
The PCV is not new, but it's working fine. The drivers side bank of pistons has blowby like you wouldn't believe, the passenger side is pretty good for as many miles as are on it. The plugs are a tan color, the number 5 plug (front drivers side) was a pretty tan-white color. They aren't very old IIRC. I'll know more about what it's doing tomorrow when I get my oil pressure gauge hooked up. The temp runs 195 to 200 degrees. The only time it ever gets any higher than that is the first warm up before the thermostat opens the first time. Then it goes up to 215 and falls right back down to 195.
Trending Topics
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Thread Starter
|
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
With pretty fresh 5w30 but a ~6 month old NAPA filter I had 50psi cold idle in park, had less than 10 hot idle in park. With a fresh FL1-A filter and 15w40 Super Tech oil, I have ~20psi hot idle in park, and I've not seen it lower than 10psi in gear. Even with it idling like crap. Anyone have a spare 2150 carb in good shape the want to sell cheap?
