Oil Pressure -- oil breakdown by heat?

[lovemycamaro]

I have a 96 Z28. It runs well, and doesn't use oil. The problem is that between changes as the oil gets more miles the pressure drops off at idle.

I changed the oil about a month ago and the pressure had been holding. However, just this weekend, I was stuck in city traffice, and the engine ran hot -- not too hot just up near the red. While it was hot I noticed that the oil pressure was always going into the red unless I kept 1500 RPMs. I thought that after cooling down the problem would go away. It didn't. Yesterday and today, when the engine is warm but no ways near that hot, the pressure still falls off.

Did the oil break down because of the heat? I am thinking that a synthetic might hold up better to the higher temps of an LT1 engine, but mine has 97K miles using a good grade Castrol oil. Would it be bad to switch to a synthetic?

Thanks for any thoughts.

[FormulaLT1]

Has the car been driving normally ?. If so sounds like a faulty oil pressure send unit. What is the pressure that you consider low?

[Hypsi87]

Originally Posted by lovemycamaro

I have a 96 Z28. It runs well, and doesn't use oil. The problem is that between changes as the oil gets more miles the pressure drops off at idle.

I changed the oil about a month ago and the pressure had been holding. However, just this weekend, I was stuck in city traffice, and the engine ran hot -- not too hot just up near the red. While it was hot I noticed that the oil pressure was always going into the red unless I kept 1500 RPMs. I thought that after cooling down the problem would go away. It didn't. Yesterday and today, when the engine is warm but no ways near that hot, the pressure still falls off.

Did the oil break down because of the heat? I am thinking that a synthetic might hold up better to the higher temps of an LT1 engine, but mine has 97K miles using a good grade Castrol oil. Would it be bad to switch to a synthetic?

Thanks for any thoughts.

well if you are opening you bypass vlave because of a clogged filter, then that could as well be the reason why. You won't break down oil by overheating your car. I think the smoke point on Oil is like 460*F or around there and that is under normal atmopheric pressure. On your car, it is pressurised so, the smoke point temp raise to alot hotter pressure.

Oil break down is mostly from being flung and chopped and splashed and used.

Unless you are running a turbocharger

[Morley]

I believe he was referring to Viscosity breakdown...doubtful that is happening. what is more likely is that the oil is thinning out as it gets hotter, also may be getting diluted by crankcase contaminants, gas, water (condensation) etc.

[Twitch1]

What is the actual number registered on the oil pressure gauge? At normal road speed a 350 should be 35-40 PSI.