View Full Version : Upper rear block seal - to flexplate

03-20-2009, 04:35 PM
Now that my engine is down to the block, I noticed a, what looks to be aluminum cap and seal covering a two inch (or so) cast hole in the rear of the block, in the space under the lower intake, but above the lifters. Directly behind it is just the flex plate.

The seal now feels like hard plastic and is loose and cracking. First of all what do "they" call this seal? I looked up every possible combination of wordings and diagrams and no one identifies this seal.

So, I was just going to take out the harden rubber, clean it, degrease it, and pack it with some RTV and call it a day, cause I am not looking forward to removing the engine to bang it in and bang out a new seal...whatever it's called.

Do you guys know what I'm talking about? Would you RTV it?

03-20-2009, 04:59 PM
I think that you are refering to the freeze plug. As far as putting some rtv on it, im not sure I would do it.

03-20-2009, 05:41 PM
Interesting...Usually freeze out plugs are aloud to blow out to release block expansion from freezing fluids, right? This thing backs up directly to the flex plate. There would be now where to allow the fluid to blow out to. I'm not saying your wrong, but if it is a freeze out plug, it's in the dumbest location on Earth. I just figured it was a hole made in the casting process due to a mechanical arm holding the cast as it was being poured or something 'cause there is identical hole on the front side of the block that opens up into the timing chain cover.

What concerns me a bit is that I noticed a few drops of oil on the floor above that location- Either that or it's my rear main, but that is practically brand new...a few years old.

Thanks for the insight

03-20-2009, 06:23 PM
Yes, looks like it is just a large galley plug that opens to the lifter cavity as an example (top of the attached photo) - no coolant in that area. Clean & coat it with RTV if you like...

03-22-2009, 02:06 PM
That's the one.

03-22-2009, 02:45 PM
I believe that's just a plug for the balancer shaft bore. Some N/A 3.8L Ford engines use a balancer shaft to combat NVH.

03-22-2009, 04:34 PM
It is for the balance shaft on the Front Wheel Drive versions of the 3.8L/4.2L. You should try and find one that is in better condition or you may have an oil leak coming from the lifter valley if its in that bad of shape.