" NO OIL PRESSURE " oa331

[earnie]

ok heres the deal
i went out to get a burger and driving back i looked down and seen that i had ZERO oil pressure pulled over and shut down, started taking a look for a problem,checked the line at the gauge no leaks or defects noted,trace the line to the pressure fitting at engine no obvious problems there, disconnected the line at the gauge and turned it over and nothing came out=no oil pressure, resecured the line, disconnected at the block , cranked the engine over nothing coming out of the engine=not a plugged line or bad gauge

waiting on the wrecker to deliver her home for further diagnosis
any ideas

 

[dmetalmiki]

no oil

any oil in it?? (no seriously) if the oil filters are not blocked then something is happening at the pump..worth taking off the sump which is not a too big a job and checking the pick up screen and pump (drive) etc. keep us informed 0f the problem progress ok. and good luck.

 

[JasonS]

The military OA331 has a bypass filter which will not affect oil pressure. I agree that the next step should be to remove the oil pan.

 

[Capt.Marion]

Do you have a spare Oil Pressure Gauge and/or a spare Oil Pressure Sending Unit to try? You shouldn't have to run it for long just to verify.

Also- may seem stupid, but it sure got me- did you flick/tap the gauge to make sure the needle wasn't sticking?

 

[earnie]

any oil in it?? (no seriously) if the oil filters are not blocked then something is happening at the pump..worth taking off the sump which is not a too big a job and checking the pick up screen and pump (drive) etc. keep us informed 0f the problem progress ok. and good luck.

yes there is oil in it

 

[earnie]

Do you have a spare Oil Pressure Gauge and/or a spare Oil Pressure Sending Unit to try? You shouldn't have to run it for long just to verify.

Also- may seem stupid, but it sure got me- did you flick/tap the gauge to make sure the needle wasn't sticking?

definatly not the gauge= disconnected it= no oil coming out when cranked,=i have a oil fed direct reading gauge, no oil coming out of the block when cranked,

 

[hndrsonj]

Do you have a spare Oil Pressure Gauge and/or a spare Oil Pressure Sending Unit to try? You shouldn't have to run it for long just to verify.

Also- may seem stupid, but it sure got me- did you flick/tap the gauge to make sure the needle wasn't sticking?

He said he disconnected it at the block. That eliminates sending unit and gauge. Prolly the pump. I'd pull the pan.

 

[earnie]

The military OA331 has a bypass filter which will not affect oil pressure. I agree that the next step should be to remove the oil pan.

seing that all else is coming up blank ,dropping the pan and looking around seems like the next step=

 

[glcaines]

It could be the oil pump relief valve has failed. Again, you need to pull the pan. Very good that you happened to look at the gauge when you did.

 

[earnie]

well got her home and backed into the shop,
dropped the oil pan,

and found this, " SEE PIC " pulled the oil pump and it has a broken pin that attaches the drive gear to the pump the gear basically fell off of the pump
took the cover plate off the pump and more of the same metal bits,
the pieces are about 1/16 of an inch in length

 

[velociT]

Wow.

Thanks for updating the post and posting pics.

 

[hughscpa]

GADZOOKS!! I hope nothing else is hurt.

 

[Recovry4x4]

I encountered the no oil pressure OA331 in my wrecker once. Here's how I dealt with it!
http://www.steelsoldiers.com/deuce/3910-deuce-wrecker-engine-swap.html

 

[hndrsonj]

Actually Kenny would drain the oil then dump it in the fuel tank of the newly installed multi. Happened before will happen again.

 

[Recht71]

Make sure you check the oil pump idler gear while you have it apart . A couple of us on the site have had the bearings go bad on the gear. Good luck, lets us know if you fined anything else.

 

[earnie]

well the update, =spun a main bearing, appears to have fodded the pump locking it up,thus causing the pin to shear on the oil pump " OR THAT IS WHAT APPEARS " to have happened

as for " RECOVRY4x4"= swap to multifuel , nope
i am kinda weird in that i like this gasser, its an oddball like me
so she is down for the count
engine needs to be rebuilt/replaced.
i need the tm used to tear this thing down
and while this is going on i am thinking total restoration
and maybe since that may be this at the end a "GUNTRUCK"

any one have the rebuild book for an oa331

 

[shenkmen]

I've got zero oil pressure registering on the dash gauge in my 70 M35A2 LDT. I noticed it when it stalled while warming up. Oil pressure was present at start up.

I understand the things to check such as a well grounded gauge, bench testing the oil pressure sending switch and checking the oil pressure regulator.

Jatonka spin on oil filters are installed.

Here's my question - How long would it take for oil to come out of the oil sample port at the base of the oil filters?

Thanks much.

 

[shenkmen]

I hooked the oil pressure sending switch to shop air and and tested the resistance following the chart in cranetruck's post here - http://www.steelsoldiers.com/deuce/54195-super-low-oil-pressure-m35a2-multifuel.html#post623038

Tip - The threads on my quick disconnects match so that's how I connected the shop air. I adjust the output PSI on my compressor. To match the chart. The lowest I can register is 15 PSI so the 10 PSI test was skipped.

My results are as follows...

0 PSI .3 OHMS (should be 0 - 1 OHMS)
15 PSI 1.6 OHMS (should be 6.0 - 8.5 OHMS)
20 PSI 3.3 OHMS (should be 8.5 - 11 OHMS)
25 PSI 4.9 OHMS (should be 11 - 13.5 OHMS)
30 PSI 4.9 OHMS (should be 14.5 - 16.5 OHMS)
35 PSI 7.8 OHMS (should be 16.5 - 17.5 OHMS)
40 PSI 8.5 OHMS (should be 19 - 20 OHMS)
60 PSI 13.2 OHMS (should be 28 - 31 OHMS)

Would the resistance table be different between 60 PSI and 120 PSI units?

If so which unit (60 or 120) does the chart apply to?

Which manual is the chart from? I cannot locate it!

I'm off to fetch a mechanical PSI gauge since the above results appear screwy.

Thanks

 

[shenkmen]

The document attached in the following post indicates the above chart is for the 0-60 PSI unit - https://www.steelsoldiers.com/showth...tml#post866795

This post contains the data for both the 60 and 120 PSI units - https://www.steelsoldiers.com/showth...tml#post866736

 

[shenkmen]

Mechanical gauge says zero PSI. No oil from the sample port. The engine stalled in less than 30 seconds while checking both. It has never stalled on start up.

New motor?

or...

Pull the pan and go after the oil pump?

Please let me know your opinion.

Thanks.