Auto-Rx Customers Questions & Answers

That engine does have a reputation for sludge, so we should learn a little more before moving forward. Can you say whether over the life of the car that oil changes were done on time, every time? How many miles were driven between oil changes, what type of oil have you used, does your oil level stay the same all the time or does your oil level drop between oil changes, and how many miles has that leak been ongoing?

On the internal metal surfaces of your engine, over the years sludge will gather on that metal, cover it, keep it from being cooled by fresh oil, and when you use autorx it chemically infiltrates that sludge, producing a by-product of tiny pieces of floating sludge, which end up in your oil filter or suspended in your oil so that after the rinse stage, the metal ends up almost as clean, and therefore as effective, as when it was new. So when you use autorx, the internal metal surfaces of your engine end up pretty much as good as new.

But not so with seals, the internal rubber surfaces of your engine. The interaction of sludge on rubber is a different world from that of sludge on metal. Rubber ages and changes when covered in sludge and when that sludge is removed, its good that you now have a clean seal, but it is still one that is dried out, unpliable, mis-shapen, and no longer perfectly mating with the metal surfaces it is meant to seal. If the seal is relatively young (maybe 50k-100k miles), and the leak is somewhat recent, you can expect the seal to regain its original shape after cleaning, and then your leak stops. The age of the seal and the age of the leak are the key.

On a leaking rear main seal seal on a 180k mile sludge prone engine, its possible that the seal may never regain its original shape, and if that's true then it will always leak (see note below). The website has always mentioned that autorx cannot fix your broken parts, but in the particular case of leaking seals, that's sort of what we are hoping for. You have a seal in place right now that no mechanic would ever consider putting in another car, yet we are leaving it in your car hoping that it comes back to life. Its amazing how often seals do renew themselves after autorx, but it does not always happen, and the most challenging situation is a very old leak in a high mileage engine that is known for sludge. So the big question is: how long has your rear main seal leaked?

If you can answer these questions we'll recommend the most productive use of autorx for your rx300.

note: this leak is an annoyance and of course you want to stop it, but as long as you keep your oil level at "full", your engine will operate with the same efficiency whether this leak is stopped or not. Its a significant job to replace the rx300 rear main, it requires removal of the transmission and usually costs over $1k in labor, which is certainly not worth it as long as you can be attentive to checking the oil level.

You probably have a lot of sludge in there, given the age of the leak, the fact that your engine is on the short list of the most sludge-prone engines, and the fact that you have at times ran low on oil.  Your car requires a vigilance toward sludge beyond most other cars, because of the reasons above but also because other than this sludge problem, its known as a reliable and high quality car that can last indefinitely, as long as sludge is kept at bay.   Therefore we recommend a schedule of a sludge treatment, followed by a basic treatment, followed by maintenance doses with somewhat shorter oil change intervals.  Since you now have 185k miles on the car, that breaks down to this:

cleaning phase 1
185,000 - change oil, add one bottle of autorx, change filter
186,000 - change filter

rinsing phase 1
187,500 - change oil, change filter (no autorx is added)

cleaning phase 2
190,500 - change oil, add one bottle of autorx, change filter

rinsing phase 2
193,500 - change oil, change filter (no autorx is added)

196,500 - change oil and filter.   Begin adding 3oz maintenance dose of autorx with each oil change, change oil change interval to 5k miles, and top off your oil frequently enough that you never are more than 1/2 quart too low.

The age of the leak is important because it is proportionate to the amount of expansion you now need from the seal in order to stop the leak.  For instance if your leak started today, then there must be a new gap that wasn't there yesterday between the seal and the metal, and the oil is leaking through that gap.  However that gap is not actually new, that same gap also existed yesterday, however it was just a tiny bit smaller than it is today, just small enough that no oil was yet leaking through.  So the gap must have gotten a tiny bit bigger in 24 hours, and did so because indeed the seal is gradually shrinking, every day, due to the presence of sludge.   So what will that gap look like in a week, or a year?  It will be bigger yet.  An old leak has the biggest gap and the hardest seal, and will take the longest to reverse itself.  You will probably not notice this difference in leak gap size because whether a leak is new or old, it may not let enough oil escape to make a big difference in your oil level.  An oil level drop is often the result of oil burning, as opposed to leaking.  So if you are consuming a lot of oil and you also have a leak, you have no way to tell how big your gap is, that is, how shrunken your seal is, other than that it is in proportion to the age of the leak.