Grand Am 92 w/ a quad 4. Oil pressure or oil pump?

Question

I dropped this rebuilt engine in this car, and the oil pressure has been up near eighty psi. Well today I went on a drive about eighty plus miles. The pressure went to around forty psi and twenty @ idle. OK, so maybe there is a by pass or something, and it is stuck open. Oh, wait, now I have a 'check oil' light on. So, I check the oil. It is full, the oil is only around eight hundred miles old. It is clean and smells like fresh oil does. I don't have any valve clatter, or overheating. Is it just a wire, bad sending unit, oil filter clogged?

Answer 1

You could check the internal engine health by pulling the oil filter off and pouring the contents into a clean oil drain pan and look for that "gun powder" residue indicating a spun bearing or the like.

If this passes the test then I'd have to pull the oil pressure sending unit or sensor off and screw a good hand held oil pressure gauge to it and then start the motor and observe the oil pressures cold and then warm and then hot. IF you fall below 30 PSI on a new motor, something is wrong and I'd try to swap the motor out now before it goes past the warrranty.

Good Luck!

Answer 2

wasthe oil pump change also was the oil bypass vlv change.what you can do is cget a seprate oil gauge and hook it up that will tell you about the oil pressure

Answer 3

80 psi seems awfully high.

I think the bypass as you say, was stuck at first and then freed up and is now working properly.

It's fine and running right.

Answer 4

my grand am's oil pressure is erratic too but never that high, it ranges from 20psi. to 35psi., buy an aftermarket oil gauge if you really want to know whats going on.