View Full Version : Oil pressure

08-18-2009, 08:44 PM
Earlier this summer, whe I would pull up to a stop sign, my oil light would flicker. When I took off again, it would go out(higher rpm's)
The last couple of time that I have driven it, the light comes on and stays on after the engine gets warmed up. Today I chaged the oil, Castrol 10-30 and a can of STP and there is no change with the light. I cant hear any unusual noises like the lifters or any other knocking. I went tho my local auto parts store and ordered a new sending unit. Do you guys think that might be my problem? The car on shows 39,000 and I believe that to be correct but not sure. I will change the sending unit and see what happens.
It is a 71 vert with the 455-4 auto.
Can you give me a hint as to where the sending unit is?
I found the temp unit bu tit was dark in the shop and I didnt find the oil pressure unit.
Thanks in advance

08-18-2009, 09:33 PM
Hi Joe
The oil pressure sending unit is located on the passenger side near the oil filter assembly
My advise is don't just switch the sending unit but get your self an oil pressure meter
I myself have installed a water temp meter, a oil pressure meter, oil temp meter (engine) and a oil temp meter (transmission)
because i really like to know what is going on under the hood

08-18-2009, 09:34 PM
THe oil pressure sending unit is just above the oil filter. It has one wire plugged into it, and is screwed into the block. You will need a deep well socket to get it off....I think it's a 1 1/16" or 1 1/8".

Try going to a 10w40 weight before you assume the worst. I've had a couple engines with a flickering oil light at the stop lights. One good thing is that these engines will idle at 2psi all day long. What you really need to do is get a good mechanical oil pressure gauge and install it.

As long as you have 10-12psi per 1000 RPMs, you are fine.

If you are worried about idle oil pressure, then your oil pump has probably worn out to the point that it needs a new booster plate and clearances checked.

If you've never rebuilt one of these oil pumps before, it would be good to find someone in your area who has. It is a tough job for a beginner to get RIGHT, and doing it with the engine in the car is a pain.

Where are you located?

08-18-2009, 11:01 PM
Thanks guys, I am going to start with the sending unit since it will be the easiest.
If this proves to be wrong, I will add a gauge and go from there.
Adam, I am the one from Chanute, Kansas

08-18-2009, 11:31 PM
Not to push you or anything but
It is really easy to do both at the same time
If you do them at the same time and you only have to be down there only once
You can connect the oil pressure meter and switch on a t-adaptor (sometimes provided with the gauge)
The opinion on mechanical or electrical differ some what
mechanical is better and more accurate, electrical easyer to install and no worrys of leakage inside the car (see other treads about this subject)
Mine is electrical i only need it for the indication
Eitherway the fun part is where to locate the gauge

08-19-2009, 08:51 AM
What a pain this is going to be.
I found the sending unit but I dont have a socket to fit it.
1" is too small and 1-1/16" is too big.
I will wait til the new one gets here to see what size it really is.

08-19-2009, 11:51 AM
Great news, a 1-1/16" 6 point socket fits just fine. I got the sending unit changed and drove the car about 5 miles and the light does not come on. Must have been the problem.
I will keep an eye on it and may put a gauge on it later but I feel better now that I know what the problem was.
Eight dollars and change is alot cheaper than a total rebuild.
Thanks guys

08-19-2009, 06:41 PM
Joe, take it down the highway for about 20 minutes, then stop at a stop light. That is when the oil is the hottest and thinnest. It will have the lowest pressure at that point.

08-19-2009, 08:34 PM
Adam, I will do that but I had to drive it today between rains.
Maybe this weekend it will clear off and I can go for a good cruise in it.:Dou: