I have a pretty good oil leak coming from somewere on my engine, it is only on the left hand side (passenger), not coming from valve covers, but lower on the block somewhere but can't see it, any suggestions on what this could be? Thanks

I have a pretty good oil leak coming from somewere on my engine, it is only on the left hand side (passenger), not coming from valve covers, but lower on the block somewhere but can't see it, any suggestions on what this could be? Thanks

How low on the block? It could be the oil filter adapter. I had one that was cracked and would leak a slight amount. It could also be the oil pan gasket - or worst case the rear main seal.

I had a combination oil pan leak and filter adapter leak on my car it would leave some pretty good puddles.

Looks pretty low near the motor mount area, but it is leaking pretty bad when I drive it and is blowing back on the exhaust pipe and smoking. Thanks for the info, will check out those two areas.

Another thought based on your description of the location is that oil could be blowing out the dipstick tube. What are the stats on the engine in your car?

It's probably best to clean the right side of the block off as best you can, take it for a short drive and inspect the block for wet spots. Good luck.

Thanks Ken, cold here today so will have to wait for a little better weather to check it out.

Oil pressure sending unit is a possibility too. It's on the oil filter adapter with a wire plugged into it.
Ken is correct in that the best way to find an oil leak is to thouroughly clean the engine of all oil then watch closely for where it shows up again. Look for the highest and most forward place that oil shows up because it will always travel down and back, never up and never forward.

could be dipstick tube if up near motor mount,rotted,broken,out of hole

Buyer,
This may be a stretch, but it may be coming from a leaky fuel pump gasket and while running the fan pushes the oil all over the underneath area amking it look like a passenger side leak.
Good luck. ITO

check the location again. It's a good bet a rear main seal leak. I haven't seen a GTO with a rope seal that doesn't leak yet.