Low oil temp switch

[Cool It]

I have a 2000 5.7 EFI Bravo 2 If the low oil temp switch is going will that cause the pressure to run to low at Idle- when I come off higher speed and then down to Idle sometimes the pressure will drop below ten and it never usually drops below 20 also when it drops the alarm goes off-oil pressur at higher speed is fine at 40 psi water temp is good outdrive oils is good. also if this is the case where on the engine do I find the switch? thanks Cool It

 

[Don S]

Re: Low oil temp switch

There is no oil temp switch, there is an oil pressure switch, but it has nothing to do with the temperature. What is the SN of your engine.
When the oil pressure drops way down to below 10, what is the engine rpm, it sounds like when you are chopping the throttle completely that the engine may not be catching back up. Try coming back a little slower. Bet it works ok then.

 

[Cool It]

Re: Low oil temp switch

Oh I did mean the pressure switch- I ussually come down easy and never had a problem but now when Im coming down in rpms and I get to about maybe 1200 then into nuetral the pressure will come down and alarm will ring- dont have SN at the moment-Thanks

 

[Bondo]

Re: Low oil temp switch

Ayuh,...... If it's dropping below 10psi,....That's Not Good,.... At All......

SBCs have Oil Pressure Ports at the very Aft, center of the Block,.... Next to the Distributer,....
And,....
At the Lower Aft Portside of the Block,... Just above the oil pan rail,+ slightly ahead of the oil filter housing, or adapter....

I'd throw a Mechanical Gauge on it to See what the ell you've got goin' On......

How's the Oil Level,..??

 

[Don S]

Re: Low oil temp switch

I agree with Bondo. The fact that you get alarm and gauge saying low pressure means you are probably getting a low reading. But the mechanical gauge would be the final test to be sure.
Have you checked the oil? Does it seem real thin? Smell like gas? not sure how that would happen with EFI, or maybe over full and getting aireated?
What oil are you using?

 

[Cool It]

Re: Low oil temp switch

the mechanics did the oil change I checked -but Ill have to check again it might have been a little to full. The low pressure is not all the time only sometimes at Idle and sometimes at Idle its fine at 20 if its low at 10 I just give it a little throttle and usually back up to close to 20 so Im not sure whats going on-when I had the mechanic take a run with me and he had his electronics -guages etc everything was fine of course when he was there no alarm went off -isnt that always the case

 

[Don S]

Re: Low oil temp switch

Even with a Merc tech there with a computer, he is only able to read what the sensors tell him. IF they are wrong, so is his info.
Use the mechanical gauge and run it till you have the problem. Have a friend there to monitor the gauge and record what is happening on the mechanical gauge as compared to the helm or computer gauges. IF they all match, then you have some engine problems.

 

[Cool It]

Re: Low oil temp switch

I just ran back to the boat to check the oil again -it seems to full it is above the words that say ok range and the words point with a little arrow to the little groved section of lines that I assume is the ok range so this is showing that the oil is well past the ok range if Im reading it correctly

 

[Bondo]

Re: Low oil temp switch

little groved section of lines

Ayuh,...... That's the Full mark......

If it's Well Above there,...
That's a Problem,..... All by Itself.........

 

[Cool It]

Re: Low oil temp switch

can that be causing this alarm and the drop in pressure-Im not a mechanic at all but it seems if to much oil the pressure would be to high? but as said before by Don S if overfull it can get aireated and would that cause the low pressure?

 

[Don S]

Re: Low oil temp switch

How much in inches (or millimeters) is "well past" ?

 

[Bondo]

Re: Low oil temp switch

but as said before by Don S if overfull it can get aireated and would that cause the low pressure?

Ayuh,..... Exactly,.....

The crankshaft is Splashing In the oil...... Turning it to the Froth....

The oil pump wants to pump Oil,....... Not Air......

 

[Cool It]

Re: Low oil temp switch

probably at least an inch maybe slightly more above the top of the ok range section

 

[Cool It]

Re: Low oil temp switch

why when Im cruising at 3200 rpms the oil pressure seems fine around 40

 

[Don S]

Re: Low oil temp switch

Get the oil level right, (between add and full) and take it for a run and report back.

 

[JustJason]

Re: Low oil temp switch

why when Im cruising at 3200 rpms the oil pressure seems fine around 40

Because at higher rpm the oil is getting picked up and circulated through the engine faster than it can drain back into the pan, thereby lowering the level in the pan. At lower rpm, the level is higher in the pan, and certainly sounds like it's getting aireated by the crankshaft. (kind of like whipping fresh cream... into whipped cream)

 

[Cool It]

Re: Low oil temp switch

Thanks for the info guys -I had the mecanic that winterised the boat and did the oil change come back and check the oil -i was right to much oil he pulled some out -I was pissed this is a reputable mechanic and meanwhile I found two things that he did wrong- put in the wrong thermostat and over filled the oil- unbelievable!! well Ill run the boat this weekend now and let you know how I make out -Thanks again enjoy the holiday weekend