Hi, first post. After replacing my intake manifold gasket, I noticed a good deal of sludge in the engine. From 1 - 10, I would say the sludge situation was about a 6.
My 4.3 liter engine for a 96 Blazer has 294 k on it. I ran a bottle of Auto RX with a fresh oil change of castro gtx.
My question is, would it be harmful to leave the Auto RX in a really old engine for the recommended 2500 miles during the cleaning phase? Someone told me to change the oil after 200 miles due to the sludge that could be circulating after the clean to prevent damage to the rings. Of course, I really want to get my moneys worth from the Auto RX and dont want to drain it before its done its job, but I don't want to damage the engine either. Any help appreciated, Thanks.
If you change the oil in only 200 miles you are just wasting a bottle of Auto-RX. Maybe he meant to change out the oil filter that soon. That would make more sense but in my opinion a bit early. Change the oil filter as often as you feel necessary or if odd engine noises concern you but I would leave the Auto-RX in for the full 3,000 miles to get the full benefit. This is my forte in here, don't forget to change your PCV valve and make sure it's working OK and the hose isn't plugged.
With that many miles on it I hope you plan on doing 2 cleanings and rinses. You may want to check out the sludge cleaning listed on this sight if you think it applies to you.
As fritz says, you would be wasting Auto-Rx with only a 200 mile drain. That's fine for some cheap solvent, but not Auto-Rx.
Just change out a filter @ 500 miles. Look inside the center tube. If you've got that much material being displaced and circulating around, it will most definitely form a slit that you can see in the filter. If you find it, change out the filter again in another 500 miles ..top up as needed and continue to change filters as long as you find visible material collecting in them.
If you're willing to continue along with this process, just keep going as long as you feel comfortable with the oil in the sump (as though you were doing no treatment at all). You're removing material in a timely manner that is in excess of the oil's detergent and dispersant package capability to keep in suspension. There's no reason to dump the oil before it's due.
