Blue Devil Rear Main Sealer additive

[FTTSHO]

Has anyone ever used this? What’s it made of? How does it work?

My 2001 chevy blazer 4.3 Vortec with 103k miles had a timing cover leak. It was never enough to actually leave drips on the ground, but the bottom left corner of the timing cover was leaking. I tried tightening the bottom left bolt a little to see if that would help but it did not. Timing cover is the only thing that’s leaking.

So I was doing some research to find the best additive that can potentially save me from taking off the oil pan to replace the timing cover, then I saw this thing called “Rear main sealer” made by Blue Devil. Saw great reviews on the internet, so I decided to try it out. Believe it or not, this thing actually fixed my timing cover leak. $15 at Walmart for a bottle that can treat upto 8 quarts of oil. It’s clear liquid.

I washed the timing cover area really good with degreaser, and then I added this chemical into the engine and drove around for 3 days (regular commute to work and errands around town) and this morning I checked under the car and there is zero leak, bone dry except a little bit of dried up oil drip on the bottom of the cover and the front main seal which was probably leaking on the first day of using this additive. But this blue devil fixed my oil leak in just 3 days.

i don’t think this sealer from blue devil is snake oil. It worked great for me. Give it a try.

I heard this stuff is supposed to swell rubbers, but I just wanna know what it really is made of. If anybody knows, please let me know.

 

[blufeb95]

I found a couple versions of the SDS, looks like it works similar to the old, add a little DOT3 to the oil trick.

 

[2strokeNorthstar]

Project farm did a test on these type of additives. Some actually do have an effect. I used Lubri Moly motor oil saver and it stopped a seal leak on our CRV almost completely. It went from an everyday annoying drip on the driveway to not leaking enough to leave a drop. The area is still a little oily dirty but I'm afraid to clean it off while it's not leaking.

 

[atikovi]

Never used it as minor oil leaks never bothered me, but just like they say to never to use petroleum products to clean your brake system because it will swell the seals and make parts stick, this is exactly what you want in a seal that has shrunken and is leaking. I'm sure their chemical engineers have come up with a formula with just the right properties to do as advertised.

 

[StumblingElk]

At205 works well

 

[RedSpider]

I found a couple versions of the SDS, looks like it works similar to the old, add a little DOT3 to the oil trick.

I actually did this many years ago to a '95 4Runner that was leaving a quarter sized stain on my driveway daily. Added 2 oz of DOT3 and about a week later the drops were smaller and after a couple weeks it stopped leaking completely. Any time I changed the oil, I added it again. Never leaked again for the 2-3 years I owned it after that. Traded it in on a Sequoia, and for a year or so at least after that the 4Runner was still on the road from another local guy who had bought it from the dealer.

Dont know if I'd be brave enough to try this again on another car, but for being such an unsavory hack..... it did work.

 

[hrv]

ATP205

 

[Furious]

You would be better off using AT-205, AT-205 has a pretty good record of actually working without over-swelling.

I like Blue Devil when it comes to cars that aren't worth putting money into with a bad head gasket.

 

[blufeb95]

AT-205 and Blue Devil Rear Main Sealer are both glycol ether based.

 

[BMWTurboDzl]

Has anyone ever used this? What’s it made of? How does it work?

My 2001 chevy blazer 4.3 Vortec with 103k miles had a timing cover leak. It was never enough to actually leave drips on the ground, but the bottom left corner of the timing cover was leaking. I tried tightening the bottom left bolt a little to see if that would help but it did not. Timing cover is the only thing that’s leaking.

So I was doing some research to find the best additive that can potentially save me from taking off the oil pan to replace the timing cover, then I saw this thing called “Rear main sealer” made by Blue Devil. Saw great reviews on the internet, so I decided to try it out. Believe it or not, this thing actually fixed my timing cover leak. $15 at Walmart for a bottle that can treat upto 8 quarts of oil. It’s clear liquid.

I washed the timing cover area really good with degreaser, and then I added this chemical into the engine and drove around for 3 days (regular commute to work and errands around town) and this morning I checked under the car and there is zero leak, bone dry except a little bit of dried up oil drip on the bottom of the cover and the front main seal which was probably leaking on the first day of using this additive. But this blue devil fixed my oil leak in just 3 days.

i don’t think this sealer from blue devil is snake oil. It worked great for me. Give it a try.

I heard this stuff is supposed to swell rubbers, but I just wanna know what it really is made of. If anybody knows, please let me know.

It's an ester. This type of ester will cause all of the oil seals in your engine to swell. Depending on the condition of your seals it may work or in rare cases make it worse (i.e. cause a piece to swell and break off).

I imagine all stop leak products (Blue Devil, Liqui Moly Motor Oil Saver, etc.) use this ester.