Dear xxx I am sorry to hear of your cam shaft seal leakage. Auto-Rx is effective in stopping or severely retarding rotary seals that are leaking due to a build up of contaminants on the shaft journal and rotary seal. Normally the build up of contamination prevents the lip of the seal from making a seal due to the irregular surface of the shaft journal due to contaminants. Many times the seal is starved from a good flow of oil to keep it cool and will begin to loose its shape over time. The first order of business is to clean the contaminants from the seal itself as well as deposits on the shaft journal. And then to run a rinse oil that has a mineral oil base, which helps the polymer seal find its old memory or shape. A mineral oil base is normally associated with conventional oil. However, there are group III oils that are labeled as synthetic, but in actuality are more highly refined mineral oil stocks, that exhibit better characteristics than that of conventional oil. Pour point is better, useful life of the oil is enhanced as well. A couple of group III oils that labeled as synthetic that actually group III mineral oils are Castrol Syntec and Pennzoil Platinum. These would be two of the many choices you have to be running an oil with better low temperature characteristics than what is common for conventional oil.
The use of full synthetic or group IV oils are not effect6ive in stopping or retarding rotary seal leaks. Mobil 1 is an example of a group IV synthetic. The base of the oil is polyalkylolefin and not mineral oil. The use of group IV oils in conjuncture with Auto-Rx to stop seal leaks is not effective. These group IV oils tend to have polar additives that want to make oil cling to the parts and as a result not best for cleaning. They also tend to keep the seal limp and as a result the seal will not re-conform to the mating shaft journal. Auto-Rx has no ability to solve a leak issue due to ripped or torn seals. Please remember that you will only be running oil change intervals of 2500 to 3000 miles. Even a conventional oil will hold up fine for this relatively short period of service. A group III will easily handle the 3000 mile oil change intervals. Normally, you can switch back to a full synthetic oil after the cleaning and rinse phases of the application are complete. Although I suggest running at least one more oil change interval with a mineral oil, before switching back to a group IV synthetic. One other thing you should check out is the PCV or crank case ventilation system on the motor to be sure that excess crankcase pressure is being released properly. If this system is not functioning up to par, oil leaks become quite common. I hope this information is helpful to you. Should you have further questions please reply. Best Regards, Rich
