Hello everyone! My 1986 Brat has a moderate rear main seal leak. Changed the oil last month, had to add about a half a quart. Should I put some lucas stop leak in and take her for a long drive? Also my clutch disc is slipping pretty bad, haven't been able to floor the pedal in a long time =(  

                              Thank you, Zosojojo

No.  Replace the failing seal.

 

They obviously make that stuff for a reason because people are desperate or want one more year out of a rusted out worthless american car.

Seems like a poor solution for a Brat.

 

Peroonally I'd just plan on addressing everything that's labor intensive to get to all at one time:

rear main seal

clutch, throw out bearing, pressure place, resurface flywheel, reseal oil pan

+1 what grossgary wrote.

Never, EVER use a "stop leak" product of any kind.  FIX THE ROOT PROBLEM, don't throw a Band-Aid at it...

Stop leak a very bad idear listen to the above.

Never, EVER use a "stop leak" product of any kind.  FIX THE ROOT PROBLEM, don't throw a Band-Aid at it...

must ask why never ever use a stop leak product

 

i used to say same until i came across lucas power steering leak fixer

 

have also tried aussie made Nulon engine stop leak in my Brumbys 4 speed box to near dry up a front seal leak - which to fix proper is a bit like neeeding to poke finger down throat to scratch an itchy bottom.

 

Do you know of why the stop leak should never ever be used ?

I would only use "stop leak" if I needed a couple of weeks grace before the real fix came about. You could go up on the oil grade to slow the leak.

 

And in your case the clutch needs looking at. Do both items and be done with it. Throw on a sump gasket as well.

Stop leak isn't a lubricant, it shouldn't be in the crankcase.  It also insulates the inside of your cooling system, making it less efficient.  Besides all that, if you use it and later replace the fluid in question, there will still be some percentage of stop leak gunk in the system that you may never be able to fully remove.

Now if you're stuck in the wilderness and you don't really care about the vehicle in question, go ahead and use the stuff.  But it won't fix the problem, honestly.

most engine oil stop leak works by penitrating the seal causing it to exspand witch in turn weekens the entire seal also it dosent just weeken the one leaking seal it ruins all the seals that it comes in contact with so you would need to replace every seal gasket and oring instead of just the rear main seal no big deal if your gona replace or rebuild anyway but if you want your motor to last as is dont use engine oil stop leak

Stop leak products for transmissions and crankcases are NOT the same as stop leak products for cooling systems.  They are compatible with lubricating oil.  They contain chemicals that are supposed to soften and swell the rubber in the seals. 

 

However, in your case, the clutch has been ruined by the oil leaking out of the rear seal, so it is probably not worth trying one of these.  Pull it apart, fix the clutch and the seal all at once.   The only reason to try a seal swell in your case is if it is really dripping fast, and you can't get to it for a week or 2, but still not worth it it the clutch isn't hooking up. 

I don't like the idea of mechanic in a bottle, but I recently separated the transmission and the engine and to my surprise Autozone sold me the wrong clutch set. Upon inspection of the clutch set installed previously in the car, I found black oil and sludge EVERYWHERE. It was probably leaking for a long time. It only leaks a tiny bit, I didn't want to do want I just did again so I thought I would ask. Thank you for your quick replies. NO STOP LEAK FOR BABY!

Hello everyone!. Thank you for your posts! Here is what ended up happening... I replaced the oil pan gasket and the rear main seal. I switched from 10w-40 (part synth) to straight conventional 30. Baby's running much better now!

must ask why never ever use a stop leak product

 

i used to say same until i came across lucas power steering leak fixer

 

have also tried aussie made Nulon engine stop leak in my Brumbys 4 speed box to near dry up a front seal leak - which to fix proper is a bit like neeeding to poke finger down throat to scratch an itchy bottom.

 

Do you know of why the stop leak should never ever be used ?

I can see it for PS, where the cost of failure isn't insane, but for things like oil and radiators, I'd stay away. OIn the oil could glod something in the engine and I know of heater cores getting ruined from it going in the coolant.

I used a stop leak to repair a leaking heater core once and it ran fine for another couple years.  The core on that car was going to be quite labor intensive to get to and I didn't really care if it eventually ruined some things as it was already a beater with not much value.  It later got totaled and I drained the system while selling off parts and out came all the sludge.  There was a bunch of it still in the reservoir tank also.  While it worked, I don't think I'd use it again on a car I planned to keep around for a while.  The radiator was also pretty new and didn't have any rust/scale clogging the arteries, so that might have helped as well.

That straight weight 30 is not the best stuff to run in the winter.  It is hard to pump when cold.  10W-30 gets into the bearings faster.  

That straight weight 30 is not the best stuff to run in the winter.  It is hard to pump when cold.  10W-30 gets into the bearings faster.  

Rotella T6 for life, in everything

That straight weight 30 is not the best stuff to run in the winter.  It is hard to pump when cold.  10W-30 gets into the bearings faster.  

im in northern california. the temp never gets below 32F so straight 30 can be run year round. In the summer I will try straight 40 because the temp will not drop below 60. I will also most likely will be trying lucas oil stabilizer.   

Somehow, 30 oil seems to be not good, even on a warm climate...

 

I live at the Caribbean and have run my EA82 with 20W~50 for the past thirty years,

 

Seems like it is ideal for almost permanent (year round) Warm climates ... ...

 

Also, I agree that Stop Leaks are Dangerous on Engines and Radiators,

 

But they do Magic on Transmissions and Power Steerings...

 

Kind Regards.