Recently completed the famous CRC block seal temp fix on my 83. This is a car I had no reason to expect a water seal failure on. But I started using MMO a year ago. Could the peculiar chemicals in MMO have deteriorated the neoprene (or whatever) O-ring?

For safety, I'm switching to 2-cycle on this car (the OMP is still working).

B

 

i was under the impression that MMO was formulated to not deteriorate seals.

there may be an off chance that carbon buildup was shoring up old seals, and when the mmo loosened the buildup, the seal finally gave it up...

 

I've never heard anything about MMO being bad, most people here recommend it. Interesting that you had that problem though.

 

I have NO idea if the two are related. Just sitting here fretting.

B

 

My recent experience with MMO was in adding it to the oil. This turned out to be a bad idea, because now it smokes on startup until it reaches normal operating temperature, which it NEVER did before.

The reasons (per my analysis) are as follows - my SE had 173k miles on it before the MMO in the oil, and was driven pretty sedately by the last owner. When I got it, it likely had about 10 years of carbon build up from infrequent oil changes which helped to seal the engine as it got up in later years. When I added the MMO to the oil, it quickly ate away this sludge 'packing' that surrounded the oil control rings, and the sludge was broken down and removed with the last oil change.

Now that the sludge is gone, the oil control rings allow oil to flow past during the startup cycle when the interior parts are contracted. As the engine heats up, the seals expand to fill the gap, and the engine reseals, preventing more oil smoke.

Very annoying smoke condition given that the car never smoked at all prior to the MMO. I wish I never added it, but that's just me. Some guys just about run their car on it and never have a problem, but that's not been my experience.

On the plus side, the car has more power than ever, and seems to run much more smoothly than before! Take that for what it's worth...

 

Wow, interesting. I'm glad I poured MMO into my 20B instead of ATF. I guess I'll see if it smokes due to the sedantary, carbon-building driving it recieved as luxury car engine, once I finally get it running.

 

I put about half a bottle of mmo in my gas... i've never had a problem.

 

I always put MMO in my gas... never heard of anyone putting it in their oil...

 

i put one quart in my oil to make it leak more (i love leaks)

 

OOOOooo K... Goof ball.

 

Try some Valvoline Max Life motor oil. If after a few thousand miles it still smokes put some STP No Smoke in there. I've had great success with this in a junkyard motor and in the REPU.

Otherwise you can try the brake fluid trick which worked great on teh same motors of mine.

 

What is this brake fluid trick you speak of?

 

Brake fluid has a not-so-well-known property of causing rubber seals to swell when bathed in the brake fluid (organic, not synthetic).

What he's referring to is the use of the brake fluid to help swell the oil control rings and help prevent blow-by oil getting into the combustion chambers when the engine is first started. Unfortunately, I've also heard that the chemicals in the brake fluid will also accelerate deterioration of the rubber seals, so I may end up doing a full engine rebuild anyway, after the seals swell up, and then start to fall apart.

If anyone has done this, I'd be interested to hear the outcome. Thanks,