Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks
Sign in using an external account
Register Forgot Password?


1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck

Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!





 
Reply
 
LinkBack Thread Tools Search this Thread
  #1 (permalink)  
Old 05-01-2012, 01:32 AM
andrewscofield's Avatar
andrewscofield andrewscofield is offline
Junior User
 
Join Date: Mar 2012
Posts: 78
andrewscofield is starting off with a positive reputation.
Low oil pressure when engine is hot

So, first time posting, been browsing for a couple months now! TONS of great, knowledgable people on here, I'm stumped on my current issue.

A couple months ago I bought 1973 F250 with a rebuilt 390 and it runs great, only 30k miles on rebuild. I use it as my daily driver. I've had a couple electrical problems that were easily fixed, other than that just flushing fluids and replacing filters.

Now, the weather is starting to warm up and I'm now seeing a new problem. I have an aftermarket oil pressure gauge installed by the previous owner. When I start my drive oil pressure is great, as the engine warms up the oil pressure drops but ONLY if I am idling. As soon as I hit the gas pedal, it goes right back up to normal level.

So my question is, since the car is running great, no strange sounds or knocking, is this a normal/ok behavior or a sign of something bad? Thanks,

Andrew
Reply With Quote
  #2 (permalink)  
Old 05-01-2012, 04:41 AM
OldStyle's Avatar
OldStyle OldStyle is offline
Rusty Roller
 
Join Date: Oct 2011
Location: Santa Cruz Mountains
Posts: 1,321
OldStyle has a good reputation on FTE.OldStyle has a good reputation on FTE.
Here is a post that contains the info/fix you need. It's just the design.... No worries!

Link: http://www.ford-trucks.com/forums/11...-in-390fe.html
Reply With Quote
  #3 (permalink)  
Old 05-01-2012, 07:44 AM
bamaf150's Avatar
bamaf150 bamaf150 is offline
Posting Guru
 
Join Date: Dec 2009
Location: Mississippi
Posts: 2,136
bamaf150 is gaining momentum as a positive member of FTE.
How low does it drop? My 360 with roughly 15k miles on a rebuild idles at about 12-15psi hot, the instant the rpms come up it rises, cruises at 55-60 psi.
__________________
1976 shortbed F-100 4x4
360 4 spd
http://http://i855.photobucket.com/albums/a...Fats/764x4.jpg
Reply With Quote
  #4 (permalink)  
Old 05-01-2012, 10:11 AM
montana_highboy's Avatar
montana_highboy montana_highboy is offline
Post Fiend
 
Join Date: Apr 2008
Location: Big Sky Country
Posts: 8,215
montana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud of
That's normal for the oil pressure to fluctuate with ambient/engine temps and rpms, my 390FE with 40K on a rebuild reads 20psi @hot idle (800rpm) and 60psi @cruise (2,500rpm).
Reply With Quote
  #5 (permalink)  
Old 05-01-2012, 06:41 PM
999yards 999yards is offline
Freshman User
 
Join Date: Apr 2012
Posts: 25
999yards is starting off with a positive reputation.
I may have a problem then. I just noticed my oil psi is at 60 at start up. When then engine warms up it goes down to 40 and stays there no matter what the rpm's.

Is that trash in the oil pick up? I did notice that its time for an oil change, it pretty black and getting thin feeling.
Reply With Quote
  #6 (permalink)  
Old 05-01-2012, 06:43 PM
bamaf150's Avatar
bamaf150 bamaf150 is offline
Posting Guru
 
Join Date: Dec 2009
Location: Mississippi
Posts: 2,136
bamaf150 is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by montana_highboy View Post
That's normal for the oil pressure to fluctuate with ambient/engine temps and rpms, my 390FE with 40K on a rebuild reads 20psi @hot idle (800rpm) and 60psi @cruise (2,500rpm).
Mine had those same numbers with 15w-40w, a little lower with 10w-30w, what viscosity are you using out of curiosity?
__________________
1976 shortbed F-100 4x4
360 4 spd
http://http://i855.photobucket.com/albums/a...Fats/764x4.jpg
Reply With Quote
  #7 (permalink)  
Old 05-01-2012, 07:09 PM
montana_highboy's Avatar
montana_highboy montana_highboy is offline
Post Fiend
 
Join Date: Apr 2008
Location: Big Sky Country
Posts: 8,215
montana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud ofmontana_highboy has much to be proud of
Quote:
Originally Posted by bamaf150 View Post
Mine had those same numbers with 15w-40w, a little lower with 10w-30w, what viscosity are you using out of curiosity?
Bama, those numbers are running 15w-40 (Rotella).
Reply With Quote
  #8 (permalink)  
Old 05-01-2012, 07:54 PM
bamaf150's Avatar
bamaf150 bamaf150 is offline
Posting Guru
 
Join Date: Dec 2009
Location: Mississippi
Posts: 2,136
bamaf150 is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by montana_highboy View Post
Bama, those numbers are running 15w-40 (Rotella).
I use Rotella too and next change will use 15w-40, summers here almost.
__________________
1976 shortbed F-100 4x4
360 4 spd
http://http://i855.photobucket.com/albums/a...Fats/764x4.jpg
Reply With Quote
  #9 (permalink)  
Old 05-02-2012, 01:34 AM
Evan's F250's Avatar
Evan's F250 Evan's F250 is offline
Senior User
 
Join Date: Jan 2012
Posts: 221
Evan's F250 is starting off with a positive reputation.
Quote:
Originally Posted by 999yards View Post
I may have a problem then. I just noticed my oil psi is at 60 at start up. When then engine warms up it goes down to 40 and stays there no matter what the rpm's.

Is that trash in the oil pick up? I did notice that its time for an oil change, it pretty black and getting thin feeling.
If its getting that good of oil psi, you're fine. Be happy. Most engines I've had run 15-20 psi hot in gear idling. If the oil seems worn, change it. Use some 15w-40.
Reply With Quote
  #10 (permalink)  
Old 05-02-2012, 09:33 PM
jeff14346 jeff14346 is offline
Senior User
 
Join Date: Jul 2011
Posts: 201
jeff14346 is starting off with a positive reputation.
my 390 has about 400 miles on it since rebuild, cold psi cruising is 55-65psi
cold idle 20 psi
warmed up in gear 4psi, put in nuetral and goes to about 9psi, no noise, no issues clean oil, jump right back up at touch of throttle
using melling high volumn pump, also have the holley jets in oil passage to help slow flow to upper end, crank is turned .010/.010 on mains and rods
Reply With Quote
  #11 (permalink)  
Old 05-03-2012, 01:44 AM
andrewscofield's Avatar
andrewscofield andrewscofield is offline
Junior User
 
Join Date: Mar 2012
Posts: 78
andrewscofield is starting off with a positive reputation.
Well, thats good news, sounds like this is not a problem. With the engine warm I am getting between 30-35 while accelerating and around 10-15 while idle.

It was just kinda messin with me because the needle moves up and down so fast, I wasn't sure if it was a problem or not.

Thanks everybody
Reply With Quote
Old 05-03-2012, 01:44 AM
Reply

Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks

Tags
2008, 64, drop, engine, f150, f250, fe, fluctuation, hot, low, oil, pressure, truck, warm, warning

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump



All times are GMT -5. The time now is 07:06 PM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.5.2 ©2010, Crawlability, Inc.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup