Decreasing Oil Pressure - SailNet Community
LinkBack Thread Tools
post #1 of 4 Old 07-06-2003 Thread Starter
Junior Member
Join Date: May 2001
Posts: 17
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Decreasing Oil Pressure

I have a 34'' 1988 Sabre with a 27 Westerbeke engine (900 hours). The book states the normal oil pressure range is 40-80psi. I note that when first starting, the pressure is about 70. After approximately 1 hour it will have decresed to about 50psi. After 2 hours of continuous motoring it will have decreased to below 40. I''m afraid of the answer; I''m sure it will be expensive. Any opinions are welcome. Thanks.
primowon is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #2 of 4 Old 07-06-2003
Senior Member
Join Date: Jul 2000
Posts: 172
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 17
Decreasing Oil Pressure

Generally, low oil pressure is an indication of bearing wear. The engine oil pump can pump a certain volume of oil which is distributed to the various bearings in the engine. As these bearings wear, they allow more oil to flow past them due to a greater clearance between the bearing and the surface the bearing operates against. Eventually, the oil pump is unable to pump a sufficient volume of oil (because of the leakage) and the oil pressure begins to fall.

Oil pressure normally falls as the oil reaches a higher temperature and becomes thinner, but when it falls below the manufacturers oil pressure range it usually means excessive engine wear.

If you are lucky, it could be the oil pressure relief valve is stuck in the open position which can also cause a similiar indication. Unless the engine has been abused, 900 hours is not normally enough time to experience excessive bearing wear.

An evaluation by a good boat engine mechanic should be done before you accept the worst case scenario.

Good luck!

joub is offline  
Quote Quick Reply Share with Facebook
post #3 of 4 Old 07-07-2003
Senior Member
Join Date: Jan 2003
Posts: 105
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 15
Decreasing Oil Pressure

40 psi is not unusual for a hot diesel engine - in fact I''d say it was pretty good. If you see less than 15-20 with a hot engine at idle, there could be a problem, but some engines are even ok with that. I''d say not to worry.
fourknots is offline  
Quote Quick Reply Share with Facebook
post #4 of 4 Old 07-07-2003
Join Date: Jul 2000
Posts: 64
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 17
Decreasing Oil Pressure

I have a Perkins 30hp that does the same thing. Starts at 60 and slowly goes down to 40. Normal, don''t worry!
clayton is offline  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
W60 - No oil pressure after oil change??? pma_foyl Gear & Maintenance 9 12-01-2004 09:45 AM
Fresh water pressure, help nauticalrich Gear & Maintenance 5 07-28-2003 06:11 AM
Oil pressure alarm question i670684 Gear & Maintenance 1 12-18-2002 12:40 PM
Avon high pressure floor mikemosabe Gear & Maintenance 5 08-17-2002 03:44 AM
Engine Oil Pressure Problem msamelso Gear & Maintenance 2 02-20-2001 06:25 PM

Posting Rules  
You may post new threads
You may 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

For the best viewing experience please update your browser to Google Chrome