Is my oil pump or oil pump screen bad?
Upper and lower intake gaskets were recently changed on my 2004 Grand Prix. After
driving car for almost a week the oil pressure light comes on, I pull of road as soon as I
can and car quits. No check engine lights and wasn't running hot. It cranks, slowly but
won't start. After sitting for about an hour it started, but ran rough. I had a tow home. A
few hours later my neighbor comes over and I ask his opinion as to the problem. We go
out and it starts right up. Running smooth as can be no abnormal noises. I'm like what
the heck. Could this be clogged oil pump screen or a bad oil pump?
I would not risk ruining your engine. If oil light came on and car ran rough, I would get it to the shop and have the oil pump and the oil pressure sending unit changed out.
Sounds like it is running hot. Have the shop that did the gaskets bleed the air out of the cooling system. Sometimes when an engine overheats the oil thins out enough to make the oil pressure drop and the light on the dash comes on. Also, if you're very low on coolant the gauge or light may not warn you of the overheating condition. This is because the sending unit in the engine is designed to be submerged in coolant. If it's not it's reading air temp inside the cooling system which can be much lower than the liquid coolant temp. I actually had the same thing happen to me once. My engine overheated and the light on the dash never came on. My lower radiator hose had burst without me knowing and the cooling system was completely empty. Remove the radiator cap and check the coolant level. It's probably very low. HTH. -Jim
I thought that also Jim. All fluids are up to par. When gaskets were done I had cooling system totally flushed and filled with fresh, clean coolant. That's what has me thinking it's the oil pump or screen for it.
Oil pump or clogged screen will not necessarily make it run rough unless damage is occurring and it is ready to seize. I would think it got hot ans possibly has air trapped in the cooling system as mentioned above.
When the computer senses the engine is overheating it begins to fire alternating cylinders. The "dead" cylinders act as an air pump to help keep the engine cool enough to prevent damage. This is commonly called "limp mode". Hence the rough running. Another thought that comes to mind is that the plugs for both the oil pressure sensor and the coolant temp sensor got transposed during the repair. That gasket job is a big job. Lots of things need to be removed then replaced. I'd still have the shop check it over for you and ask them about bleeding any trapped air from the cooling system. HTH. -Jim
Looking for a Used Grand Prix in your area?
CarGurus has 3,722 nationwide Grand Prix listings starting at $879.
Search Pontiac Grand Prix Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Pontiac Grand Prix Experts