1989 B2 4x4 low oil pressure

[Jwgossett]

We rebuilt my 89 b2 about a year ago. New heads, rings cam an crank bearings, timing chain water pump oil pump ect. It's got about 8 thousand miles on the new motor. The problem is when my rpms get low my oil pressure gauge bottoms out. I get the rpms up an gauge goes to normal, the motor does not rattle when gauge bottoms out. Not sure if this is related but when I crank it up from a cold start it rattles for about 1to two seconds then goes away. Any help will be appreciated.

 

[Tedybear]

We rebuilt my 89 b2 about a year ago. New heads, rings cam an crank bearings, timing chain water pump oil pump ect. It's got about 8 thousand miles on the new motor. The problem is when my rpms get low my oil pressure gauge bottoms out. I get the rpms up an gauge goes to normal, the motor does not rattle when gauge bottoms out. Not sure if this is related but when I crank it up from a cold start it rattles for about 1to two seconds then goes away. Any help will be appreciated.

I know this will be thought of by some....Are you using the dash board gauge, or an aftermarket oil pressure gauge?

Dash board gauge is nothing more then a chumped up idiot light. It will flat line when it sees about 7lbs of pressure or less. Sense there's always a chance that sender can go bad, It's a good idea to either run a 't' fitting and hook in a manual oil pressure gauge along with the idiot gauge and then see exactly what is going on. Or to go with a manual gauge on it's own. I always liked the first option. One that will get your attention...and then the one that gives details.

Just to start things rolling....

S-

 

[RonD]

Most oil filters have an ADBV(anti-drain back valve).
When engine is shut off the ADBV closes and prevents oil from draining back down the oil passages, it is basically just a flap that is pushed open by oil pump flow then closes when there is no flow.
The "rattling" at startup could mean the ADBV is bad or not there, "most" oil filters have them not all oil filters
This wouldn't be related to oil pressure when idling

Yes, like tedybear said, the stock sender and gauge in an '89 is just an on/off setup.
Sender on the engine is an on/off switch, above 6psi it is ON, below 6PSI it is OFF

If there is no valve train noise at idle then pressure will be above 4psi.
But gauge would be at 0, switch OFF
It could be the switch is going bad as well so pressure at idle is above 7psi but switch is turning OFF.

You can convert your 1989 to a "real" oil pressure setup.
You need to replace the switch on the engine with a PS60 oil pressure sender.
And pull out the instrument panel to install a jumper wire on the back of the oil pressure gauge, by-passing the 20ohm resistor that puts needle at 1/3 when switch is ON.

 

[Tedybear]

Most oil filters have an ADBV(anti-drain back valve).
When engine is shut off the ADBV closes and prevents oil from draining back down the oil passages, it is basically just a flap that is pushed open by oil pump flow then closes when there is no flow.
The "rattling" at startup could mean the ADBV is bad or not there, "most" oil filters have them not all oil filters
This wouldn't be related to oil pressure when idling

Yes, like tedybear said, the stock sender and gauge in an '89 is just an on/off setup.
Sender on the engine is an on/off switch, above 6psi it is ON, below 6PSI it is OFF

If there is no valve train noise at idle then pressure will be above 4psi.
But gauge would be at 0, switch OFF
It could be the switch is going bad as well so pressure at idle is above 7psi but switch is turning OFF.

You can convert your 1989 to a "real" oil pressure setup.
You need to replace the switch on the engine with a PS60 oil pressure sender.
And pull out the instrument panel to install a jumper wire on the back of the oil pressure gauge, by-passing the 20ohm resistor that puts needle at 1/3 when switch is ON.

Not to hijack this. Would that also work on a 4.0 OHV 1995 Explorer?

S-

 

[RonD]

Not to hijack this. Would that also work on a 4.0 OHV 1995 Explorer?

S-

I think last year for Rangers was 1996, after that the resistor was internal, part of the gauge, so it couldn't be done/jumped.
Can't say on the Explorer

Picture of the backs of instrument clusters here: http://www.rowand.net/Shop/Tech/FordOilPressureGaugeFix.htm

And the jumper wire needed.

PS60 sender often won't fit without an extender, its much wider than the switch.

 

[Tedybear]

I think it might work re: sensor size. Ours has the extension on the engine block. (I hooked up our Mac oil pressure gauge when we changed the oil. Fair pressure considering 235000 miles on the odometer ) Sorry about the hijacking thread. Back to our original post...

Sent from my SAMSUNG-SM-G530A using Tapatalk

 

[Jwgossett]

I know this will be thought of by some....Are you using the dash board gauge, or an aftermarket oil pressure gauge?

Dash board gauge is nothing more then a chumped up idiot light. It will flat line when it sees about 7lbs of pressure or less. Sense there's always a chance that sender can go bad, It's a good idea to either run a 't' fitting and hook in a manual oil pressure gauge along with the idiot gauge and then see exactly what is going on. Or to go with a manual gauge on it's own. I always liked the first option. One that will get your attention...and then the one that gives details.

Just to start things rolling....

S-

i have an aftermarket gage I'm going to put on it when I get home. Thanks

 

[Jwgossett]

Most oil filters have an ADBV(anti-drain back valve).
When engine is shut off the ADBV closes and prevents oil from draining back down the oil passages, it is basically just a flap that is pushed open by oil pump flow then closes when there is no flow.
The "rattling" at startup could mean the ADBV is bad or not there, "most" oil filters have them not all oil filters
This wouldn't be related to oil pressure when idling

Yes, like tedybear said, the stock sender and gauge in an '89 is just an on/off setup.
Sender on the engine is an on/off switch, above 6psi it is ON, below 6PSI it is OFF

If there is no valve train noise at idle then pressure will be above 4psi.
But gauge would be at 0, switch OFF
It could be the switch is going bad as well so pressure at idle is above 7psi but switch is turning OFF.

You can convert your 1989 to a "real" oil pressure setup.
You need to replace the switch on the engine with a PS60 oil pressure sender.
And pull out the instrument panel to install a jumper wire on the back of the oil pressure gauge, by-passing the 20ohm resistor that puts needle at 1/3 when switch is ON.

I think I'm going to put a aftermarket gauge change the oil make sure I get a GOOD filter an maybe use a bottle of Lucas.

 

[Jwgossett]

I know this will be thought of by some....Are you using the dash board gauge, or an aftermarket oil pressure gauge?

Dash board gauge is nothing more then a chumped up idiot light. It will flat line when it sees about 7lbs of pressure or less. Sense there's always a chance that sender can go bad, It's a good idea to either run a 't' fitting and hook in a manual oil pressure gauge along with the idiot gauge and then see exactly what is going on. Or to go with a manual gauge on it's own. I always liked the first option. One that will get your attention...and then the one that gives details.

Just to start things rolling....

S-

what weight oil you Guys using?

 

[Tedybear]

what weight oil you Guys using?

When I had the Bronco II with the 2.9 I was using full synth 5w40 with the FL-1A motorcraft filter for a long time. It had a bad set of bearings and oil pressure issues when we purchased it, so eventually I bumped it to 10w40.

The explorer we now have is rated 5w30. But it's got 230k+ on the engine. So 10w30 is currently installed for the spring/summer months. I might just leave it there year round....

S-