No Oil Pressure

[devildog11]

I have a 4.3l Merc V6 with no oil pressure at all. I've changed the oil pump,oil, and filter but still no pressure. GM oil pump primer pumps oil but it just flows out no pressure behind it. I'm at my wits end any help would appreciated.

 

[Bt Doctur]

Re: No Oil Pressure

You need a dist housing in the hole to direct the oil thru the galleries, not just a rod spinning the pump shaft.

 

[bruceb58]

Re: No Oil Pressure

Are you saying there is no pressure indicated by the guage? Have you installed a mechanical pressure guage to confirm this?

 

[devildog11]

Re: No Oil Pressure

I've tried a mechanical gauge and also a GM oil pump primer with a rod and aluminum spacers to direct the oil. Still no pressure. Trying not to remove the engine anymore.

 

[bruceb58]

Re: No Oil Pressure

You turning the adapter clockwise?

 

[devildog11]

Re: No Oil Pressure

No counterclockwise for oil pressure clockwise just gives me bubbles

 

[devildog11]

Re: No Oil Pressure

Thinking lifters or oil passage clogged somewhere

 

[bruceb58]

Re: No Oil Pressure

No counterclockwise for oil pressure clockwise just gives me bubbles

Why would you spin it counterclockwise when normal rotation is clockwise?

 

[Silvertip]

Re: No Oil Pressure

Are you saying the engine has no oil pressure when running? Or did you just rebuild it or work on it and it now has no oil pressure. Lots of oil pumps are changed because of low/no oil pressure but it is rarely the pump. Worn Rod, main, and cam bearings that are worn or spun affect oil pressure.

 

[devildog11]

Re: No Oil Pressure

I'm saying that it was rebuilt last spring then sat winterized and this spring has no oil pressure. Oil is pumping but ever so slowly. Oh and it turns clockwise for pumping.

 

[bruceb58]

Re: No Oil Pressure

So..this engine has never been run? Did you pre fill the oil filter? Masy just take more spinning of the oil pump adapter. Does the adapter that you use have the disc that blocks off the oil galley like a distributor does?

 

[devildog11]

Re: No Oil Pressure

The boat has been ran since rebuild then winterization. Oil pump primer is the same GM would use in a pro shop. Oil does pump to the headers just with not alot of pressure.

 

[bruceb58]

Re: No Oil Pressure

I would keep on running the primer. Sounds likeit just hasn't primed itself yet. What RPM are you running the drill at?

 

[devildog11]

Re: No Oil Pressure

Its a craftsman hi-speed 19.2v cordless and you can see the oil come up thru the tube for the mechanical gauge just very slowly. So i have a sneeky suspicion that i am losing oil pressure somewhere in the system. I was told that I may have to adjust the rocker arms a little by the guy who rebuilt it as a valve may be not closing entirely. Im no longer in the area of this guy otherwise I would have gladly dropped it off with him. Like I said earlier I prefer not to have to pull the engine again.

 

[bruceb58]

Re: No Oil Pressure

Please don't take offense at this question but are you sure you have enough oil in the engine?

How long do you run your drill? I bet it has just lost its prime and it will take awhile to get going again. Can you hand move your engine? Might be worth moving it 45 degrees run the drill...then repeat.

 

[devildog11]

Re: No Oil Pressure

yes there is enough oil and reads max on the dipstick. I have run the drill for 4 min straight with no reading from electronic or mechanical gauges. I"m going to check what the fee is to crate the motor to the guy who rebuilt it.

 

[bruceb58]

Re: No Oil Pressure

I would give him a call first. Obviously the pump has lost prime and there must be a way somehow to get it primed again. I know the trick when you first start a new engine is to pack it with grease but obviously you can't do that now.

 

[JustJason]

Re: No Oil Pressure

At this point i'd just pull the pan off and see if someone forgot to put the pickup tube on.

 

[Polar_Bus]

Re: No Oil Pressure

yes there is enough oil and reads max on the dipstick. I have run the drill for 4 min straight with no reading from electronic or mechanical gauges. I"m going to check what the fee is to crate the motor to the guy who rebuilt it.

I read you are trying to prime run the pump, with a "cordless" drill? You also have the correct oil primer type tool, that has the correct special priming tool with the distributer bushing to pass oil flow to the cam galleys?

That being said, when you start turning the pump shaft it should only take about 5 seconds or so, to prime, then you should feel a substantial amount of torque "resistance" on the drill. If you have a thick and cold 30wt. type oil, I would suspect the pump resistance would slow down a cordless drill from spinning quite a lot. I have raced SBC for years, and when I would do my newly rebuilt "oil system prime" I used a 1/2 Craftsman electric drill, and I always felt the drill really load up once the oil started pumping...
so like others commented you either have a bad pump, or the pickup is not below the fluid level.

Not to be a wise *****, but do you know if your engine builder packed a little grease in the oil pump to guarantee good initial prime suction?

 

[devildog11]

Re: No Oil Pressure

Yes the oil pump was primed with grease for a good priming. the drill loads up when it pumps and the pickup screen/ pickup tube is pressed into the pump housing. the oil pumps just not with any readable pressure.