Help for Detroit 8V71Tis Low oil pressure at idle

[tomrealest]

At idle one of my Detroits is only showing 3 to 5 lbs oil pressure. Once I increase the rpm's it increases to 45 lbs. Need help finding a 2 cycle Detroit guy in the Boca Raton-Delray Beach area. Most guys will travel. Would appreciate some advice or referrals for a Detroit mechanic on the East Coast of Florida.

 

[jim rosenthal]

What did it used to show? It isn't that unusual for DDs to have low oil pressure at idle when hot. Is this a big change?

 

[SKYCHENEY]

Mechanical gauge? If not, put a mechanical on there to make sure the reading is correct.

 

[SEVEN]

Those gauges fail all the time. My transmission gauges showed 180 and 220 PSI. I added mechanical gauges directly in the the engine rooms. Both read 125 PSI. Right where it’s supposed to be.

 

[Briankinley2004]

5 PSI is not abnormal at idle with warm oil. Here is one of many posts on boat diesel regarding that

https://boatdiesel.com/Forums/index.cfm?CFAPP=0&Forum_ID=108&Thread_ID=60894&Search=2&SR=1

I'm not telling you everything is OK cause I don't want to be part of ruining your engine but I think if its getting 45 psi at higher RPM you should be ok. A mechanic could tell you for sure. I know my 12V71's run pretty low at idle with warm oil

Also are you running straight 40 weight oil? If your oil is too thin that may make pressure lower. Also you may want to have an oil analysis for fuel dilution

 

[tomrealest]

Oil was changed 20 hours ago with Detroit 40 weight oil. I don't remember it being so low but can't honestly say I remember.

This was with a mechanical gauge in the engine room. Will try with a new gauge.

Appreciate the help.

 

[Scarlett]

Wouldn’t the alarm go off if the pressure was really that low?

 

[Briankinley2004]

Wouldn’t the alarm go off if the pressure was really that low?

yes if it is working. The thread I posted talks about it is normal on some engines for the alarm to go off when engaging gears on 71 series. I haven't experienced this

 

[luckydave215]

Mine will "ring the bell" with hot oil if I go into reverse with too much way on - 5 knots or so.
The manual says it's normal.

 

[Play'N Hooky Too]

Mine will "ring the bell" with hot oil if I go into reverse with too much way on - 5 knots or so.
The manual says it's normal.

Same here. When running at idle while lining up on my slip, I'll get a few short rings every time I bump it into reverse if I have any forward momentum at all.

 

[dottieshusband]

+1 on being a sender issue. They get old and tired. They are also effected by low voltage, like at idle. I doubt it is the problem, very very rare to be a problem, but there is a simple spring loaded pressure valve forward of the oil pump.. but I doubt that is the problem.

 

[BUSTER]

At idle one of my Detroits is only showing 3 to 5 lbs oil pressure. Once I increase the rpm's it increases to 45 lbs. Need help finding a 2 cycle Detroit guy in the Boca Raton-Delray Beach area. Most guys will travel. Would appreciate some advice or referrals for a Detroit mechanic on the East Coast of Florida.

That is perfectly normal for a 2-cycle Detroit once the oil is up to operating temperature.

 

[racclarkson@gmail.com]

My port motor always chimed-in briefly at gear shift RPM drop. Last couple of cruises the bell rings almost all the time at idle after a run. I was due for an oil change, and hoped new 40 Wt. might solve it. No so. The mechanicals say I’ve got 7-8 PSI at idle while cruising at 1800 RPM shows +\- 45 PSI. So I’m thinking that 7 PSI sender has had its day. I’m going to a 5 PSI unit and forget about it.

 

[luckydave215]

Isn't the standard sender 3 psi?

 

[racclarkson@gmail.com]

My book says 7

 

[racclarkson@gmail.com]

BTW, anyone have the p/n for a 5 and/or 7 psi switch?

 

[racclarkson@gmail.com]

BTW, anyone have the p/n for a 5 and/or 7 psi switch?

Disregard. Found a 4 psi at Sam's.