Tim,

I disagree. Higher viscosity oil WILL raise oil pressure, not mask it. Oil pressure goes down due to tolerances increasing to at or above acceptable OEM specs between some or many key components, including the pump itself. Higher viscosity oil, which remains thicker at higher temps, will actually help fill those gaps left when thinner oil flows out or off of surfaces.

As for the flush, there is a small chance the oil pressure is low due to clogged passages or a partially blocked oil screen. A flush could (not a guarantee) help clear up some of these conditions, thus also raising oil pressure. If he tears down the engine, replaces the pump and screen, but the low pressure is caused by partially blocked passages, a new pump won't fix the tapping noise caused by low pressure.

It isn't automatically necessary to tear down an engine, especially when the block must be raised substantially off of the motor mounts in order to get the oil pan off.

It took more than 20 years for the oil pressure to get into this situation. Raising the pressure via thicker oil could keep the engine in service for many more years before a teardown is needed.

If the flush and thicker oil DOESN'T fix his problem, then a teardown may be warranted. However, I prefer to start with the easiest potential solution and then work up to the more difficult ones.

Reatta Guy
And I have to disagree with you. Without ANY indication of where the oil pressure pressure is, why on earth would you flush the engine or increase the viscosity of the oil?! It could just be a bad sender!
My background is an automotive technician or instructor since 1978 and the first 7 years of my career were spent at an Oldsmobile dealership as an ENGINE technician. I am currently teaching automotive technology in the GM ASEP program and GM Training center. I am ASE master certified, a GM World Class Technician and a Technical Advisor for the ROA. I have diagnosed and repaired more automobiles then I care to remember.
That being said, I do value your opinion on the situation with John's 307. I just don't believe that "remedies" in a can are in ANY way a substitute for solid diagnosis.
Tim

He said it was tapping, which sounded to me like starving lifters.

There is no way to offer a solid diagnosis over the internet. But, tapping+oil light= low oil pressure. Yes, an oil pressure gauge (even a $10 import from a big box store) will just confirm that is almost certainly the problem in a 20+ year old engine.

Using higher viscosity oil is a recipe for disaster. This engine is DIRTY, lifter plungers are siezed, no oil is delivered to some rocker arms, and at least three pivots are worn out. That's why it 'ticks'.
Now, you want to keep running it? Why don't you fix it? After finding acceptable oil pressures, you can start with new lifters and rocker arm assemblies. Even then, I don't think it will last very long because some of the valves were starved for oil (for a long time).
Save your money and use it to overhaul this engine while you still can.

ok everyone autozone in las vegas rented me an oil guage very nice i pulled the oil sending unit from the block with the 1 brown wire installed the guage it had between 6 psi and 7 psi at idle and when i reved it up it shot up to 24 to 25 psi of oil pressure thanx for you help in advane what is next and also all of your patience john

as far as the poi ;ight it only comes on when im coming to a stop then shuts off john real quick when i hit the brakes on the off

John,
Was your engine cold or fully warmed up when you checked your oil pressure? Oil pressure will be higher with the engine cold and it will drop as the engine warms up. This is caused by the oil thinning slightly as it warms up and the engine internal clearances opening up as the engine warms up.
Tim

John, with all due respect, don't take this engine very far from home. It is worn, dirty, and it needs major help. Your oil pressure drops so low that the 'oil' light comes on, which means you have no oil flow. The gauge confirmed that your oil pressure light works just fine, and your maximum pressure isn't enough.

Using higher viscosity oil might raise pressure, but it is a false assumption that your moving parts are being lubricated. They aren't. Your valves aren't opening all the way because the worn pivots relaxed valve train tolerances. That 'tick' sound you hear is the slop. Dirt has blocked oil flow, and the only way to fix this situation is to remove the dirt/varnish/crud manually, and replace all worn and stuck parts.

John,
I agree with simpyconnected. Your engine may still be able to be repaired, but if you continue to drive it, you may damage it beyond any economical repair. 6 to 7 pounds of oil pressure is barely enough to keep the lifters pumped up, let alone maintain internal pressure and be able to direct oil to the pivots and rocker arms through the push rods.
Worn rod bearings, main bearings and camshaft bearings are all likely causes of low oil pressure, but a failed/worn oil pump can be the cause, too.
Now it is decision time, do you repair/overhaul what you have, replace it with a remanufactured 307 or buy a used engine and swap it into your Riviera. The answer depends on your financial stuation, how attached you are to the car, your level of mechanical knoledge and availability of tools and space to do the work.
Maybe there are some local Riviera or Buick folks that can help you out!
Tim

ok guys i went back to autozone got the guage again i will retest as all i did was iinstall the guage start it and not warm it up i will repost this weekend or end of the week with engine warmed up john thanx in advance for everyones patience

in neutral at idle warmed up the oil pressure shot up to 16 now and reved up warm it shot up to 34 not what is the next step guys i also did a oil change and filter 10 w 30 john

also guys i bought new pushrods rocker arm pivets and rocker arms for cylinders 3 nd 5 anyone know the torque setting to bolt them down john

can anyone help with the torque setting on the rocker arm bolts john

Shop manual states 28 Ft Lbs for the hold down bolts

thank you very much i changed 4 push rods 4 rocker arms and 2 pivots a lot quiter john

So, is your problem completely fixed now?