Faulty Oil Pressire Readings

[Gary J.]

The oil pressure gauge on myn newly aquired 1969 427-390 coupe reads faulty and is it just a matter of the gauge needing to be replaced or another issue? The pressure needle shows 35 lbs without the car running and when running pegs out at the 70 lb maximum reading.
Is the replacement of the gauge a straight forward procedure of removing the center cluster, any C3 tips for removal is appreciated.
On another separate question unrelated, is there a way to distinguish P02 corvette hub caps from similar passenger car hub caps of that era or are they one in the same.

Thank you for your insight.
Gary

[Jeffrey S.]

Re: Faulty Oil Pressire Readings

Gary,
The passenger car PO2 has a flat center cap where the Corvette (and Riviera) center cap has a raised center. The Riviera has a different emblem.
Jeff

[Russ S.]

Re: Faulty Oil Pressire Readings

Passenger car P02s are 14 inch. I don't know about Rivieria-I didn't know buick used P02s but I think Rivieras would have been 15 inch. Corvette of course are 15 inch.

[Ralph S.]

Re: Faulty Oil Pressire Readings

Monte Carlo & Impala were 15 inch P02 with flat center

[Terry M.]

Re: Faulty Oil Pressire Readings

The oil pressure gauge on myn newly aquired 1969 427-390 coupe reads faulty and is it just a matter of the gauge needing to be replaced or another issue? The pressure needle shows 35 lbs without the car running and when running pegs out at the 70 lb maximum reading.
Is the replacement of the gauge a straight forward procedure of removing the center cluster, any C3 tips for removal is appreciated.
On another separate question unrelated, is there a way to distinguish P02 corvette hub caps from similar passenger car hub caps of that era or are they one in the same.

Thank you for your insight.
Gary

It sounds like your oil pressure gauge has malfunctioned -- however, just to be sure you should disconnect the oil pressure line at the engine (above the oil filter on the side of the cylinder case) and install temporarily a good mechanical gauge. I have duct taped the gauge to the outside of the windshield for a trip around to warm up the engine and get hot & cold readings at idle and at speed. It is good to record those readings someplace for future reference. If the pressure is good it will be time to R&R the gauge.

This is a fairly involved process, and I suggest you consult your copy to the 1969 FSM (Factory Service Manual) for a step by step of how to do it. There are two studs at the bottom of the instrument bezel that will be hard to find/see. Your copy of the 1969 AIM (Assembly Instruction Manual) will show where those are.

They can be reached with a GOOD set of 1/4-inch drive extensions, flexible coupling and 7/16-inch socket. If your set of tools is not of good quality investing in a good 1/4-inch drive flex coupling will pay dividends for you. The nut does not have to be removed, only loosened to give clearance to the center console. There is a slot in the center console. You may need a deep or semi-deep socket, but try a shallow first, then go to the deeper if necessary. Clearance is at a premium here. Oh, and pray that Bubba has not been there first.

If all this sounds like more than you want to tackle, a professional can do it, but you really want someone who knows early C3s. This is the kind of job none of us likes, but it does get easier the more often you do it.

[Russ S.]

Re: Faulty Oil Pressire Readings

Monte Carlo & Impala were 15 inch P02 with flat center

Ralph, If you are right on this,what were the 14 inch P02s used on?

[Michael D.]

Re: Faulty Oil Pressire Readings

...On another separate question unrelated, is there a way to distinguish P02 corvette hub caps from similar passenger car hub caps of that era or are they one in the same...

Flat cap:

Corvette:

If memory serves, the stamped wheelcover and cast metel spoke basket are the same for GM 15" P02s. Raised, crossed flags center ornament is Corvette only.

[Ralph S.]

Re: Faulty Oil Pressire Readings

14 inch was used on Chevelle & Camaro

[Gary J.]

Re: Faulty Oil Pressire Readings

Terry
thanks fr the detailed explanation, sounds like I need to add this to my winter project list. I hate having the car apart when the weather is good here in New England. So far, with only 64,000 miles on the odometer and being the 4th owner The car has been fairly Bubba free.

A very good lesson on the the P02s story, thanks again.

Thanks again to all
Gary

[Paul O.]

Re: Faulty Oil Pressire Readings

Gary

As far as the PO2 go for 15 inch covers the main section (Wheel Cover) are basically the same it was the center trim cap that varied by model. A quick guide is if the raised/hump section at the outer most part of the cover lip is raised at the outer edge it is a 15" cover if the raised or hump is in the center of the outer ring it is a 14" cover. Also if you have an early production 69 some have been seen with all PO1's and a mix of PO1's and PO2's say till around 1500 S/N. Hope this helps.

[Terry B.]

Re: Faulty Oil Pressire Readings

A real good thread with pictures regarding PO-1 and PO-2 hubcaps.

https://www.forums.ncrs.org/showthre...ht=C-3+Hubcaps

Terry