Hello all I just purchased a set of Fel-Pro Intake Manifold Gaskets for my 90 Dakota 3.9L V6. On the gaskets, my question is why on the rear coolant passage ports designed the way that it is? I noticed the small hole but, I am wondering if the hole should be opened up to the size of the passage? I know on all my small block 318s and 360s the gasket portions was matched up to the port. and not 90% blocked like these are. Even the 92+ gaskets have the port open. I will attach a photo to try further help and the 92+ gaskets. Thank you.

 

Have you got the intake (plenum) off yet? What did they do with the original gasket? The old gasket will give you an answer to what to do.

 

Hello, the previous owner already had a set of the Fel Pros installed on the truck. I did happen to find a picture that might be of help. Still wondering if I should use a utility knife to trim out the port? Looks like the Mopar ones are fully matched?

 

I'm sure there's a reason Fel-Pro made the holes small, and it wasn't just because their big hole punch broke. Sometimes, slowing down the flow of coolant through the engine helps it cool better. Perhaps this is one of those instances?

If you weren't having cooling problems with the old gaskets, I would install the new ones as-is.

 

The 92 & later 3.9 is a different engine (Magnum.)

Your picture is misleading, too. The way it should be is that on one bank, the rear water passage is wide open on one side and restricted on the other (the intake openings have to be matched) and on the other bank, the set up is reversed. So for sake of discussion, the bottom intake manifold is shown backwards. Does this make any sense?

I've looked at the other gasket sets that RockAuto sells. The Victor-Reinz set has the small holes, too. As Tom said, if it didn't overheat, leave it be. My guess is that it's left over from when Chrysler used carburetors and was meant to slow the coolant down and help avoid carb icing. My best guess is that open it up or leave it restricted probably has little consequences either way. (Just my 2 cents worth.)

Interesting that Fel-Pro includes a little tube of sealant. In the V8 Magnum engines, they don't and nothing is mentioned about using sealant on the water cross-over passages (I use copper RTV, btw.) I've had lots of experience with coolant spoiled intake gaskets--a smear of RTV can help prevent that I hope.

 

Thanks guys. I realize the pictures might be messed up but, my biggest concern for whom done this rather or not there is any true benefit. That being said, I went ahead and installed the gaskets as is. Yes, they did supply a small thing of RTV but, I never used it nor did I use the cork end gaskets. I bought "The Right Stuff" from Advance Auto Parts and used that around the ports and intake ends. Now, to see if there is any leaks as I get this truck buttoned back up.