Engine noise

I drive a 1996 Geo Prizm, 1.6 148000 miles

After the engine cools down, I have to sir

and wait until the tempiture gauge needle

reads in the middle in order the loud noise of the engine dies down. (cold or hot days) Is this due to the age of the car?

Pls be more specific about the noise. Does it occur after you have shut off the car (run on or “dieseling”)? Are you saying the car needs a large amount of warm up time before the noise goes away when started and run?

Either case calls for diagnosis. If the noise is loud but quiets down when the oil warms up, that could point to an oil pump issue. What weight of oil are you using in the car?

Can you describe the noise?
I’m wondering about the [possibility of gummed up lifters (tappets).
How’s the maintenance been? Have you kept up with your oil changes?

I have had the car for three years and preformed the neccessary maintenance, The noise sounds like a loud roar

the wieght oil has been 20/40 one time I used high preformance oil this past summer.

Is the engine revving, is that the reason you have the loud roar? Perhaps you could pop the hood and check.

If so, Then perhaps your temp sensor is malfunctioning and telling the ECU the engine is cold. This may not trip a fault code, because without some signal to compare it to the ECU accepts the signal as true, and since it thinks the engine is cold it’ll bypass the oxygen sensor loop and the engine will freely run rich (fast) without the ECU knowing a problem exists.

Thank you. I will have this looked into!!!