Bolisk
Well-known member
(Note: Before you respond to this thread . . . please read at least the first paragraph.)
I would really appreciate it if someone could provide factual technical reasons for why people should not use synthetic oils in older car components (engine, tans, diff). I’m not all that interested in hearsay (i.e. he/she said, I heard, I was told no to . . . arguments). If you’re potential response uses one of those hearsay statements . . . please don’t respond to this thread, because there are plenty of hearsay threads already.
This discussion bothers me because it seems as if nearly all oil companies have admitted that synthetics are better in nearly all conditions. Most auto manufactures are now offering synthetics in their new cars off the line. That said, for the life of me, I cannot understand why anyone would ever suggest that synthetics are not the preferred choice for our older Corvettes, or at least a good option.
Classic example: I was recently read the riot act, with regards to using synthetic oils, by a well known Corvette shop owner. When I inquired as to why not, he always came back to three arguments:
1) Synthetic’s leak from the seals.
2) Synthetic’s cause limited slip/posi units to chatter (i.e. make noise).
3) Synthetic’s do not work with the tolerances of the older components.
He regaled me with stories of countless customer cars that have come into his shop with synthetics leaking out the seals and differentials making horrible noises. Then, as expected, when he replaced the synthetic with conventional lube and a bottle of the GM friction modifier (key point there), all the problems went away.
What bothers me is that he didn’t take the time to root cause the actual problem. His mind was made up before he started the job. He simply did what he knew from experience and left it at that. Please don’t misunderstand me. This is 100% fine for him, his business, and his customers who most likely just want the problem fixed. It’s not necessarily in his best interest as a business owner to spend the time to determine if the customer used the correct synthetic and the proper amount of additives in their differential. It’s far better for him to go with something he knows works and then move on to the next job.
Having said that, the negative side affect to this practice is that ultimately this results in yet another corvette owner who now believes that synthetics are the root of all things evil, and they post their experiences on these forums, therefore perpetuating the “potential” myth that synthetics do not work in our Corvettes.
Now it would seem to me, when I look at the three arguments above, that if the seals (or gaskets) leak, then I need to replace the seals/gaskets. If the differential makes noise; then that would lead me to believe that there isn’t the proper amount of friction modifier added to the gear lube (regardless of conventional or synthetic). So with my limited knowledge, the first two arguments don’t seem like arguments at all. They seem like side affects of semi-worn out seals, and not mixing the correct amount of additive. The only argument that holds water is the argument regarding tolerances. Problem is no one ever has any technical data to back that up.
Yes, I’m aware that the Eaton FAQ webpage says that Eaton recommends conventional lube. Now, that is the ONLY document that has me questioning synthetics in my diff. Having said that, I’ve sent letters and e-mails to Eaton asking for details as to why (making a point to ask for technical details)? I also asked them if in fact their FAQ simply regurgitated what their documentation from the 60’s and 70’s say, and whether that information is now stale. To date, I have not received a response. If I ever receive one, I will post it here.
So, back to my plea. Is there anyone out there that knows (with technical data) why synthetics should not be used (if not preferred) in our old cars?
Best regards to all,
JonR
I would really appreciate it if someone could provide factual technical reasons for why people should not use synthetic oils in older car components (engine, tans, diff). I’m not all that interested in hearsay (i.e. he/she said, I heard, I was told no to . . . arguments). If you’re potential response uses one of those hearsay statements . . . please don’t respond to this thread, because there are plenty of hearsay threads already.
This discussion bothers me because it seems as if nearly all oil companies have admitted that synthetics are better in nearly all conditions. Most auto manufactures are now offering synthetics in their new cars off the line. That said, for the life of me, I cannot understand why anyone would ever suggest that synthetics are not the preferred choice for our older Corvettes, or at least a good option.
Classic example: I was recently read the riot act, with regards to using synthetic oils, by a well known Corvette shop owner. When I inquired as to why not, he always came back to three arguments:
1) Synthetic’s leak from the seals.
2) Synthetic’s cause limited slip/posi units to chatter (i.e. make noise).
3) Synthetic’s do not work with the tolerances of the older components.
He regaled me with stories of countless customer cars that have come into his shop with synthetics leaking out the seals and differentials making horrible noises. Then, as expected, when he replaced the synthetic with conventional lube and a bottle of the GM friction modifier (key point there), all the problems went away.
What bothers me is that he didn’t take the time to root cause the actual problem. His mind was made up before he started the job. He simply did what he knew from experience and left it at that. Please don’t misunderstand me. This is 100% fine for him, his business, and his customers who most likely just want the problem fixed. It’s not necessarily in his best interest as a business owner to spend the time to determine if the customer used the correct synthetic and the proper amount of additives in their differential. It’s far better for him to go with something he knows works and then move on to the next job.
Having said that, the negative side affect to this practice is that ultimately this results in yet another corvette owner who now believes that synthetics are the root of all things evil, and they post their experiences on these forums, therefore perpetuating the “potential” myth that synthetics do not work in our Corvettes.
Now it would seem to me, when I look at the three arguments above, that if the seals (or gaskets) leak, then I need to replace the seals/gaskets. If the differential makes noise; then that would lead me to believe that there isn’t the proper amount of friction modifier added to the gear lube (regardless of conventional or synthetic). So with my limited knowledge, the first two arguments don’t seem like arguments at all. They seem like side affects of semi-worn out seals, and not mixing the correct amount of additive. The only argument that holds water is the argument regarding tolerances. Problem is no one ever has any technical data to back that up.
Yes, I’m aware that the Eaton FAQ webpage says that Eaton recommends conventional lube. Now, that is the ONLY document that has me questioning synthetics in my diff. Having said that, I’ve sent letters and e-mails to Eaton asking for details as to why (making a point to ask for technical details)? I also asked them if in fact their FAQ simply regurgitated what their documentation from the 60’s and 70’s say, and whether that information is now stale. To date, I have not received a response. If I ever receive one, I will post it here.
So, back to my plea. Is there anyone out there that knows (with technical data) why synthetics should not be used (if not preferred) in our old cars?
Best regards to all,
JonR
