If you are talking about the EXHAUST manifold then most of the time it's the valve cover gasket that is leaking oil. REPLACE VALVE COVER GASKETS.
If you are talking about the intake manifold then it has 2 rubber gaskets in the front and rear of it that leak oil real bad. If oil is on the left are right top sides of the intake manifold were the valve covers are then it will be the valve cover gaskets that are leaking oil.
Valve cover gaskets leaking oil onto exhaust manifold/s. Bad valve seals. (if oil level drops) Bad PCV valve. Allowing oil into intake manifold/throttle body area.
If you are not seeing any leaks, it is possible that the gasket is leaking on the bottom of the intake manifold, causing the engine to burn the oil.
Intake manifold leaks will cause the engine to idle rough and get poor fuel economy. An exhaust manifold will have no symptoms other than the sound of the leak.
The exhaust manifold.
In my 1995 Pontiac Bonneville the oil leaks out the intake manifold and drips onto the exhaust. An engine that has a gaping hole will hold no pressure.
No, it will not cause oil leaks.
1st step is to have your thermostat checked or replaced and make sure there aren't any leaks. The 3.1L engine is apparently famous for intake manifold leaks. If you have any oil in your coolant or coolant in your oil try to get this fixed ASAP. A new manifold gasket shouldn't cost too much and will prevent your engine from being trashed. One way to tell if there is coolant in your oil is to look for some beige colored gunk on your oil fill cap. That's just my experience.
I switched to full synthetic engine oil in 2001 and have no oil leaks on my 1995 Ford What makes you think you will have leaks? And if you think you will have leaks then why would you use synthetic? You will have no leaks that you would not have with conventional oil.
Engine? 3.1L V6 are notorious for intake manifold gasket leaks. get it fixed soon or your engine is at risk. My Lumina had oil in coolant and coolant in oil. If there is tan foamy stuff on oil fill cap, coolant is in oil too.
Yes anything running a northstar engine is prone to oil leaks especially if you use a synthetic oil this is because the block is made from aluminum which is more porous then steel so fluids can get past the seals in an effort to fix this gm started pressurized molding in 2000
The oil leaks in via the injectors! This knowledge helps people avoid these Landrover junk buckets, (most expensive scrap metal you can buy! ha! ha! ha!) --------------------------------------- [ bad intake manifold gasket ]
your engine will run too lean.