Oil leak after switching to Amsoil

[mark4Jesus]

I bought this 86 Aspy last July. Not sure what oil the PO used. Changed oil yesterday and used Amsoil. I had a very small leak at the rear engine seal before. Since switching to Amsoil the leak has increased. I have read that when switching to a synthetic oil, weak seals will begin to leak or leak worse. Will the synthetic oil recondition the seals so that they will eventually stop leaking, or do I need to switch to a regular oil. I hate seeing that expensive Amsoil on the ground. The previous leak was not serious enough to make me want to replace that seal.

[WingAdmin]

Higher detergent oils can clear out sludge and crud that was blocking up a leaky seal - which is great because that sludge is no longer in the engine, but not so great because that sludge was keeping the oil leak at bay.

[themainviking]

You need to replace the seal, to stop the leak, and then put the Amsoil back in. In the mean time, drain it carefully into a clean container so that you can save it. Or conversely, let it finish the job of cleaning out your engine, drain and discard it, replace the seal and any others that begin to leak while this is going on, and then refill with nice new clean oil (synthetic or not - your choice). My studied opinion is that the leak will not stop, and even if you go back to regular dino oil, it will still leak.

[mark4Jesus]

Going to order seals and replace engine and final drive seals. Both have leaks.

[artgrantz]

Viking is correct. I know from personal experience that once the synthetic oil finds that path to the sunlight going back to dino won't stop it. Run that oil as he suggested and find any other bad seals, then replace them as needed.

[OnPapasWing]

Is it possible that Rotella could cause the same symptom? I just changed to Rotella but haven't had it on the road yet since changing it. Been to busy with other projects. PO was using Valvoline (I believe).

[mark4Jesus]

I am going to replace rear engine seal and final drive seal sometime next week. Trying to figure out parts form diagrams right now.

[artgrantz]

Is it possible that Rotella could cause the same symptom? I just changed to Rotella but haven't had it on the road yet since changing it. Been to busy with other projects. PO was using Valvoline (I believe).

It doesn't always happen, but if there is any way for the oil to get out the synthetic oil will find it. If you aren't using synthetic you probably won't have a problem and if you are it may still be OK.