Can I use "Auto-Rx" or "Motor Flush" to flush engine?

I change oil for my Chevy Malibu (1999)every three months. Recently, I found the oil was very dirty at the change, and the mechanic told me it needs an engine flush. He suggests using a product called “Motor Flush” available at Pepboy. A friend told me “Auto-Rx” is a better option. Does anyone have experiences using the Auto-Rx for cleaning the engine? I usd it once for cleaning the transmission for my other car before changing the transmission fluid. Any information and suggestion is appreciated as I am unsure it the chemical may damage the engine of an old car.

Assuming you change the oil on a regular basis, I don’t see the need for either of these products. When you change the oil you remove the accumulated dirt form the engine.

If you’re concerned, do another oil change in about 1,000 miles. That should be just as good as an engine “flush.”

I would strongly discourage any effort to flush either an engine or transmission with such products.

How many miles do you drive in 3 months (between changes)? How many miles are on the car?

The oil is supposed to be dirty when you change it. That’s part of its job.

It sounds to me like the mechanic was just trying to sell you an extra service. I wouldn’t bother with it. If you decide to do it for some reason, any standard product will do.

I’m curious to know what brand of oil you’re using AND what type of driving you do. Do you take a lot of very short trips around town? Or do you drive the highway at 55mph on a regular basis?

What is the car being used for?

If it REALLY is full of sludge, I’d do this:
Drain the oil
Put a brand new HIGH QUALITY (Bosch or Purolator) oil filter on the engine
Fill the crankcase with automatic transmission fluid - if you search the internet, you’ll be able to find one with "high detergent"
Make sure the oil dip stick indicates FULL, but not over full
Start the car and let it IDLE in the driveway for 20-30 minutes.


DO NOT REV the engine!!!

Just let it sit there and idle.

After 20 - 30 minutes, shut it off. Now do a “regular” oil change.

Drain the ATF from the crankcase
Remove the dirty oil filter
Install a NEW high quality oil filter
Fill the engine with fresh engine oil of your choice
Check the dip stick to assure proper fill level in the crankcase

I drive to work one hour (one way)strait every day, but that’s local drive, and I do not make short stops. I change the oil at the garage, and I don’t know which brand, and i assume that’s just the common brand. I do not drive a lot except for driving back and forth from my work place. I am wondeing why I need to “fill the crankcase with automatic transmission fluid” rather than the oil? Thanks. Lee

I always thought that oil was supposed to get dirty if it is doing its job. If you think that the oil is getting too dirty between changes, I would do this: After running the car, put your hand on the oil filter and see if it is hot. If it isn’t, oil may not be circulating through the filter. If this happened to you at only one oil change, I wondder if the filter that had been installed was defective. After your oil and filter change, keep your eye on the dipstick and see if the oil becomes really dirty.

Filling a crankcase with automatic transmission fluid, adding a quart of kerosene, using Motor Flush (which is similar to kerosene) are all age-old methods for cleaning out dirty/sludged engines. However, that’s not to say they’re advisable. If you have engine sludge and you use one of these cleaners, you’d better drop the oil pan to clean out the sludge chunks that are now clogging the pickup screen on your oil pump.

If you’ve changed your oil ever 3 months (as you said in your opening post), then I seriously doubt you have any sludge in your engine that you need to worry about.

Again - How many miles??

And you should need to do nothing re: flushing.

I would not flush an engine at all. Look at it this way. Anything that is dislodged is going to do one of 2 things.
One is that smaller particles are going to constantly clog the oil filter more than normal.
Two is that larger particles will not pass through the oil pickup screen, effectively shutting off the flow to some extent. In some cases, it may shut it off entirely.

Just change it regularly, both as to mileage and time.

This type of driving pattern is near ideal for a car. I’ve seen cars go 200,000 miles and mor without any prblems with such driving and changing oil and filter every 3000 miles.

I know most the regular posters here don’t advise using a engine cleaner and I have never used one myself but if I wanted to try one I would use the Auto-RX product. It uses a process that works slower than most cleaners so it shouldn’t harm anything in the process of cleaning things if yoou follow the instructions. I may be wrong but I think the product would work great.

Everywhere I go they want to use some kind of flush junk in my engine. I politely say that I don’t believe in it. I use Castrol Syntec synthetic oil and I need no flushing. If youre oil looks dirty, your oil is working.

I have a place do my oil changes during cold weather and they used Castrol Syntec too and they know better than to add stuff to it, but they want to make money too.

If you want to clean your oil, change it at 1,000 miles, oil only. Change it and the filter at the usual time after that. Inother words: Run for a month, change oil only and do a full change two months after that.