6.9 idi oil pressure - Diesel Truck Forum - TheDieselGarage.com
Thread Details Posted by courtem, this thread has received 54 replies and been viewed 16800 times.

 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 55 (permalink) Old 10-13-2013, 02:46 AM Thread Starter
Junior Member
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
Exclamation 6.9 idi oil pressure

1984 6.9 idi rebuilt and now has about 3k miles since the build. The engine runs smooth, no unusual noises, and delivers 21 mpg highway. Recently the oil pressure has dropped to the bottom line of the normal range on the factory gage. I figured it was just the factory gage being nothing more than an indicator that oil pressure is present. I put on a new sending unit and this did not change the reading. I checked voltage at the wire that connects to the sending unit and voltage is present (this is an indicator that the ICVR is operating). This old truck has a low voltage instrument cluster with a voltage regulator that feeds the temp, fuel, and oil pressure gages. I installed a direct reading gage and confirmed that at idle the pressure is not enough to register, and high rpm the engine develops about 17 psi. My diagnosis is probably a stuck oil pressure regulator. When I pulled the oil cooler I found that the pressure regulator is staked in and not easily removable. A search around here disclosed that a replacement part is not available for this engine. Ford has discontinued this part and no alternate part is available. And there is no overhaul kit to renew the existing regulator. My idea is that I need to get the existing regulator out of the oil cooler header without bugging it up. Then I MAY be able to polish the plunger and bore, if necessary, find a replacement spring. My question is: has anyone else had this problem, and what was your solution? Thanks for any advice that you all may provide. Is this Ford's way of telling me to buy another truck?
courtem is offline  
Sponsored Links
Advertisement
 
post #2 of 55 (permalink) Old 10-13-2013, 02:54 AM
Aimless Wanderer
 
Join Date: Jul 2011
Posts: 929
Points: 50,683
Thanks: 29
Thanked 359 Times in 285 Posts
Quote:
Originally Posted by courtem View Post
1984 6.9 idi rebuilt and now has about 3k miles since the build. The engine runs smooth, no unusual noises, and delivers 21 mpg highway. Recently the oil pressure has dropped to the bottom line of the normal range on the factory gage. I figured it was just the factory gage being nothing more than an indicator that oil pressure is present. I put on a new sending unit and this did not change the reading. I checked voltage at the wire that connects to the sending unit and voltage is present (this is an indicator that the ICVR is operating). This old truck has a low voltage instrument cluster with a voltage regulator that feeds the temp, fuel, and oil pressure gages. I installed a direct reading gage and confirmed that at idle the pressure is not enough to register, and high rpm the engine develops about 17 psi. My diagnosis is probably a stuck oil pressure regulator. When I pulled the oil cooler I found that the pressure regulator is staked in and not easily removable. A search around here disclosed that a replacement part is not available for this engine. Ford has discontinued this part and no alternate part is available. And there is no overhaul kit to renew the existing regulator. My idea is that I need to get the existing regulator out of the oil cooler header without bugging it up. Then I MAY be able to polish the plunger and bore, if necessary, find a replacement spring. My question is: has anyone else had this problem, and what was your solution? Thanks for any advice that you all may provide. Is this Ford's way of telling me to buy another truck?
That valve sticking open dumps oil pressure from the pump right back into the pan. I had an 83 and lost the engine over that. After rebuilding it but not realizing that valve was stuck open, I lost oil pressure shortly after the rebuild. After pulling the engine from the chassis again, I found the cam bearings down to copper, mains scrubbed pretty good, and the rods almost perfect. I was able to get the new valve at the time, (1992) replaced all the bearings, and all was fine for almost 60K more before I sold the truck.

The question I seek an answer for is simply; why, or why not?
Backslap is offline  
The Following User Says Thank You to Backslap For this addition to TDG:
courtem (10-13-2013)
post #3 of 55 (permalink) Old 10-13-2013, 03:07 AM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
Quote:
Originally Posted by Backslap View Post
That valve sticking open dumps oil pressure from the pump right back into the pan. I had an 83 and lost the engine over that. After rebuilding it but not realizing that valve was stuck open, I lost oil pressure shortly after the rebuild. After pulling the engine from the chassis again, I found the cam bearings down to copper, mains scrubbed pretty good, and the rods almost perfect. I was able to get the new valve at the time, (1992) replaced all the bearings, and all was fine for almost 60K more before I sold the truck.
The parts department at the local ford dealer says that the header went out of production about two years ago. I really don't want to pull the engine again. I work in my home two car garage. The truck stays outside and only the engine gets in the house! I have read that volume of flow in this engine is probably more important that pressure. I have not loaded the truck down since I put it back in service, so there has not been prolonged periods of high power requirements. If I can find another cooler in a salvage yard, that may correct the issue, but I may end up with the same problem that I have now. There is probably a reason for that old engine being in salvage?
courtem is offline  
post #4 of 55 (permalink) Old 10-13-2013, 03:13 AM
Aimless Wanderer
 
Join Date: Jul 2011
Posts: 929
Points: 50,683
Thanks: 29
Thanked 359 Times in 285 Posts
Quote:
Originally Posted by courtem View Post
The parts department at the local ford dealer says that the header went out of production about two years ago. I really don't want to pull the engine again. I work in my home two car garage. The truck stays outside and only the engine gets in the house! I have read that volume of flow in this engine is probably more important that pressure. I have not loaded the truck down since I put it back in service, so there has not been prolonged periods of high power requirements. If I can find another cooler in a salvage yard, that may correct the issue, but I may end up with the same problem that I have now. There is probably a reason for that old engine being in salvage?
The one in salvage could be cooked from busted heads, blown head gaskets, melted pistons, or a few other items that plagued the early 6.9 diesels. I'd bet there is an NS1 part someplace. Check with a dealer and ask them to run under that search. The 7.3 used the same cooler so should be readily available. My valve was jammed open from chunks binding it's operation from the engine letting go prior. Lot's of early to mid 1990's IH school busses used the same engine and there should be some of those around also.

The question I seek an answer for is simply; why, or why not?

Last edited by Backslap; 10-13-2013 at 03:15 AM.
Backslap is offline  
post #5 of 55 (permalink) Old 10-13-2013, 03:27 AM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
Quote:
Originally Posted by Backslap View Post
The one in salvage could be cooked from busted heads, blown head gaskets, melted pistons, or a few other items that plagued the early 6.9 diesels. I'd bet there is an NS1 part someplace. Check with a dealer and ask them to run under that search. The 7.3 used the same cooler so should be readily available. My valve was jammed open from chunks binding it's operation from the engine letting go prior. Lot's of early to mid 1990's IH school busses used the same engine and there should be some of those around also.
Thanks, those are very good points and I will give it a try.

Question: with the header in my hand, I push in with a brass rod and I felt the plunger move to the bottom of the bore (where it stayed). did I open or close the port through which the oil flows?
courtem is offline  
post #6 of 55 (permalink) Old 10-13-2013, 03:30 AM
Aimless Wanderer
 
Join Date: Jul 2011
Posts: 929
Points: 50,683
Thanks: 29
Thanked 359 Times in 285 Posts
Quote:
Originally Posted by courtem View Post
Thanks, those are very good points and I will give it a try.

Question: with the header in my hand, I push in with a brass rod and I felt the plunger move to the bottom of the bore (where it stayed). did I open or close the port through which the oil flows?
You opened the port and if it stayed recessed into the bore, a good portion of the oil flow will bypass the engine and be returned to the pan.

The question I seek an answer for is simply; why, or why not?

Last edited by Backslap; 10-13-2013 at 03:45 AM.
Backslap is offline  
post #7 of 55 (permalink) Old 10-13-2013, 03:38 AM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
that confirmed what I thought I understood about the way the regulator operates. I hate to lose the truck engine for the sake of a simple spring loaded valve. especially since there are designs that ford could have used that permit the rebuilding or replacement of the regulator valve. a simple spring loaded ball on a machined seat works just a well, and some of those were adjustable by shimming the pressure spring or turning the plug in a little deeper.
courtem is offline  
post #8 of 55 (permalink) Old 10-13-2013, 01:48 PM
Aimless Wanderer
 
Join Date: Jul 2011
Posts: 929
Points: 50,683
Thanks: 29
Thanked 359 Times in 285 Posts
Quote:
Originally Posted by courtem View Post
that confirmed what I thought I understood about the way the regulator operates. I hate to lose the truck engine for the sake of a simple spring loaded valve. especially since there are designs that ford could have used that permit the rebuilding or replacement of the regulator valve. a simple spring loaded ball on a machined seat works just a well, and some of those were adjustable by shimming the pressure spring or turning the plug in a little deeper.
That valve is just staked in place so would be easy to replace with a ball and seat cartridge although you may need to open up the hole in the casting to make it fit. If not, plug the original hole, drill and tap though the mounting boss, (end cap) and run an external line back into the oil pan which would require welding on an external bung and a line. Not really hard to do just takes a little ingenuity of which I lack......
Sherman likes this.

The question I seek an answer for is simply; why, or why not?
Backslap is offline  
post #9 of 55 (permalink) Old 10-13-2013, 05:25 PM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
I have been soaking the spring and plunger port with CRC "Break Er Loose" penetrating oil. While I was spraying the oil I noticed a small port on the filter side that goes into the valve chamber. I applied compressed air to that port to make sure it is open, and the valve activated. I tried it several times and sometimes it opens, and other times only partial opening and sometimes nothing at all. I think a small slide hammer puller may take the sleeve out of the hole. I gently pushed the steak dimples back by tapping the seam line between the sleeve and the header assembly lightly using the corner of a small chisel like a wedge so that it did not cut into the soft header metal. There is a small dimple in the end face of the sleeve. I put the end of a ***** punch in that dimple and gave a light tap and observed that the sleeve rotates fairly easily. That is good news to me! I do not have a slide hammer, but I am going to look for a small one like could be used to remove small bearings for pressed assemblies. I think the sleeve will come out with the proper tool. Then I will try to polish the parts and the bore to achieve freedom of movement. IF I can do that, then I will reinstall plunger, spring and top sleeve by re-staking the rim of the valve and give it a try. Does anyone see any obvious flaws in this procedure?
courtem is offline  
post #10 of 55 (permalink) Old 10-13-2013, 09:25 PM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2011
Location: alabama
Posts: 93
Points: 49,396
Thanks: 10
Thanked 6 Times in 6 Posts
Garage
Smile

The penetrating oil has been "soaking" for about 4 hours. I tried to wiggle the valve again and was able to hook it in one of the 3 holes near the top of the bore and got it started out. I placed an open end wrench at the bottom of the top lip and used a socket as a fulcrum point to lift the valve free of the header. There was a fairly heavy coating like a varnish on all of the surfaces that was binding the valve. I polished all of the mating surfaces to a nice bright clean finish and periodically ran the plunger in to check the fit. Once it was all clean and with a light coat of oil the plunger falls out of the sleeve with gravity. There is no radial play that I can detect. The spring did not show any scuffing on the outer circumference so I think it is good. I gave everything a good coat of clean engine oil and put the valve back in the header bore and re-staked it there. Out of curiosity I measured the outside diameter of the exposed sleeve at the staked end and found that it is larger than the hole to which it mates on the engine block. I think this could have been installed without re-staking, but would have been more difficult to reassemble to the engine without the staking of the valve. So the header is ready to go back on the engine. I hope it works to boost oil pressure! That truck is not leaving my yard until it has oil pressure!
courtem is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Diesel Truck Forum - TheDieselGarage.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

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

Password:


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

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
7.3 idi smoking under back pressure Mike444z 7.3L and 6.9 IDI (Pre 1994) 2 03-15-2012 04:53 PM
7.3 idi non turbo eng oil cooler courtem Introductions 5 01-01-2012 04:27 PM
Oil Filter for 7.3 IDI crenshawjm 7.3L and 6.9 IDI (Pre 1994) 3 04-12-2007 01:32 AM
Any way to boost Low pressure oil pressure? CSIPSD 1994-2003 7.3L Power Stroke 6 10-10-2006 02:15 AM
oil temp and oil pressure sending units???? AUGSX 2003-2007 6.0L Power Stroke 3 04-05-2006 01:30 AM

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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On

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