need to make sure my gen VI oil pressure relif valves are correct...have a part # that came up on a search on here #25161284 just want to make sure if this is the correct one and are their 2 to change ? thanks Rob

Yes 25161284
Remove the one in the center, replace the one closest to the block.

My suggestion here is to replace the original oil relief valves with GM part number 25013759. This valve will allow more oil to be fed through your oil cooler before opening on differential pressure to stop to much bypassing back to pan. Stock valve has an approximate 11 psi max before it opens and the number above will see approximately 30 psi before it opens. I would recommend using a high volume heavy duty pump also like the Melling 10778 series pumps.

Best Regards,
Ray @ Raylar

Ray, On our gen 5 and gen 6 builds we replace 1 valve with the 11 lb stock and the other 1 with with the 30 lb. Are you saying replace them both with the 30 lb valves? I have found that leaving the center 1 out as 1BIGJIM suggests limits the oil getting to the upper end greatly reducing valve spring life.



Also Ray I will call tomorrow to order the throttle body and other items.

getting confusing ???

Brian,
I am not sure how leaving the center valve out would affect oiling in anything but a positive way. It can only be left out if you are not using the factory oil cooler passages in the block though. Leaving the center bypass out allows the oil to flow straight into the engine without having to make a couple of turns going through the GM block passages. That would help oil flow if anything, not hurt it and is the way I have always assembled them.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

+1. Do not use the passages on the block, plug them both. I remove the center relief valve completely and install the 30lb. valve on the filter pad. Use a billet remote adapter to connect the cooler lines, be sure to line up the supply passage in the adapter, the return goes to the center. Good Luck.

what are the differences between the #25161284 vs #25013759 ?

This thread now has me thinking about my set up.

I found this diagram and from what I remember when I took the engine apart and put it back together, the system looked like this...

http://www.marineengine.com/parts/me...ER+AND+ADAPTOR

Now where are the 11lb "valves" you are talking about?

They are not in the diagram you have, they are in the block where the filter adapter mounts. I think Ray got mixed up on the PN's, as the 25013759 is the 11lb, and the 25161284 is the 30lb bypass valve. As BillK said, the one in the middle valve. redirects the flow around some 90deg turns to get to the rear external cooler as used on trucks. Not used on most boats, so without the valve it is a straight shot into the engine.