hotjava66

Been researching and reading threads on this subject, trying to figure it out. Want to check mine while I have the engines out to see if this may be contributing to my oil temp issues. Is there any way to tell which valves are in the filter pad, and what is the proper arrangement? There does not seem to be a consensus on whether certain holes should be valved, plugged or open. Which way should they be set up and is there any drawing or link to a schematic of the filter pad and what belongs where. I am running the stock remote adaptor and cooler system off a gen IV or V 454 mag. Thinking about switching to thermostatic coolers but need to make sure this is correct first. I apologize that this has been covered many times but there seems to be many opinions on it.

CAPTAIN JACK

I don't know if you have read this thread its a good one. I always saved it because its one of my favorite, hope this helps you!! Its long but ALOT of good info for what I think your searching for. The thread will show pictures where to put the bypass valve and which one, also which one to remove. Enjoy!!

click on link below

http://www.offshoreonly.com/forums/g...-hardware.html

28Eliminator

Here is another good read with more pictures to help understand. The 30lb oil bypass valve is GM part 25161284. It goes in the outside offset hole, or you can plug it. The bypass in the center can be removed as it is only needed for use with an external oil cooler that taps on the block, like trucks use. The pictures in the thread show those holes in the block next to the oil pan which are plugged on mercruiser motors.

http://www.offshoreonly.com/forums/g...i-502-a-2.html

28Eliminator

I wanted to update the information I provided.
After working on a friends 496, I see where the conflicting information and debate on these bypass valves are coming from. On all the 454mags and 502 mags that I have worked on, the oil leaves the Merc oil filter pad, goes through the filter to the cooler and returns on to the Merc oil filter pad. That is not the case on this 496HO I am working on. It leaves the Merc oil pad (different setup), then goes to the filter, then to cooler, then to one of the base pad holes on the block next to the oil pan. These oil holes are plugged on the 454 & 502 models and are not used. All of the info I have posted has been for 454/502. The information above is correct for either of these motors, but not for a 496ho.

I may start another thread when I get the motor back from the machine shop, take pictures, and look at the oil flow on this 496.
Cheers