Timing cover oil leak

[Quentin Earl]

I recently purchased a 86 Grand National, It has a major oil leak!! I degreased the engine, started it up and let it idle for about 10 mins and it didn't leak. I drove it down the road about a mile and punched it once. When I stopped oil was pouring from the front cover. The front oil seal isn't leaking, however I pulled the intercooler, fan and balancer and noticed that the top bolt on the crank sensor bracket was missing. Could this be where the oil is coming from? also what is the size of the bolt? Do I need to use thread sealer when I replace the bolt?

 

[Paul Lohr]

You got it. That may be where the oil is coming from.

Pretty sure that bolt hole is open to the crank case. Clean the oil out and use some thread sealer. There are many thread sealers out there and many opinions about them. I have used Taber's Gasket Sealer for years without problems. Yes, it works well on threads also. Permatex Aviation Form-a-Gasket is also a good thread sealer.

A 5/16" x 18 x 1" bolt should do the trick. The bolt can be longer than 1" since there is probably 1.75" in the block before the bolt bottoms out. You could use 1.25" or 1.50" long if you want.

 

[87gnguy]

I recently purchased a 86 Grand National, It has a major oil leak!! I degreased the engine, started it up and let it idle for about 10 mins and it didn't leak. I drove it down the road about a mile and punched it once. When I stopped oil was pouring from the front cover. The front oil seal isn't leaking, however I pulled the intercooler, fan and balancer and noticed that the top bolt on the crank sensor bracket was missing. Could this be where the oil is coming from? also what is the size of the bolt? Do I need to use thread sealer when I replace the bolt?

Yeah, that's probably it. Mine leaked from there for TWO YEARS. I could never get it to stop. I tried replacing the timing chain cover gasket, I used ARP thread sealer, teflon tape, RTV... Nothing worked. Turns out my cover was warped just a grunt in that spot. Then before I could buy a new cover my motor started knocking from the bottom end real bad and I ended up replacing it. The bolt that goes in there has a 13mm head on it with fine threads. I think it's a 1/4 inch bolt size. Not sure though.

 

[Quentin Earl]

Got it!!! Got a 5/16 bolt, thread sealer and put it back together. No more leak, however while I was testing it out the intercooler fan blades came apart. One was already missing know I have only one left. Ha. Guess I'll get a new one. Thanks for the info!!!