I have an '86 GXL with a bad engine as well as two S5 engines, one that should be ready to run. I pulled the front cover off the S4 this weekend to get it cleaned up and got the S5 on the engine stand for the swap.

I have been planning on using RTV on the oil pan when I put the new front cover on, but can I use it instead of a gasket on the front cover face as well? Just wondering what the best way is to install the new front cover. Thanks.

 

It would work, but using a gasket would be cleaner and have little chance of a leak developing.

 

You'll need the front cover gasket to help hold the oil passage o-ring in place.

http://mazdatrix.com/faq/oring.htm

 

I remember reading this site but couldn't find it when I tried looking for it again. I think this is why I was thinking silicone to seal the front cover.

Despite reading through that page, I am still a little confused. Since I am using a S5 engine with a S4 front cover, do I use the first recommendation that says to use the o-ring and silicone for a gasket and throw away the teflon ring?

 

No. Use the teflon ring, the o-ring, and the front cover gasket for the 89-92 engines. The s4 front cover should work fine.

 

I thought the site said to do it the other way since I have the "earlier style" S4 housing. Or am I reading it backwards?

 

Has anyone else done this swap (S4 cover on S5 engine) that can verify these instructions?

 

Anyone? I'm hoping to get the new front cover installed tonight.

 

Look at your front iron. If the whole if big, then use the teflon washer. If it's a s4 iron, then just use the o-ring + rtv to hold it in place.

You do what is necessary for the block, not the front cover. S4 iron = no teflon S5 iron = teflon+o-ring. Never needed a front cover gasket for either year. Mainly s4.