Motor Flush

[jiminbartow]

I was listening to a car repair show on the radio today and heard a method for flushing and cleaning an engine. They said that the next time you are ready to change your oil, pour in a quart of automatic transmission fluid and run the engine at idle for an hour, then change the oil as usual. They said that, unlike solvent type motor flush products, automatic transmission fluid has a lot of detergents and also has enough lubrication qualities to maintain good lubrication while cleaning. Even though they had modern cars and engines in mind for this, I see no reason why it would not work on a Model T. What say you, regarding this motor flush procedure? Jim Patrick

[Allan]

Jim, when I replaced a rod in Henrietta, by taking out the old one through the pan inspection hole underneath, I found a pile of gritty stuff caught between the pan and the horseshoes around the inspection hole. I suspect it was carbon from the underside of the pistons. While it was lodged there, it was doing no harm. I'd hate to see it liberated to circulate through the motor. Sometimes it might be better to leave some things well alone until they can be tackled in a more appropriate manner.

Allan from down under.

[VowellArt]

I don't know, that is a mixed bag that is, some folks think it is ok to use detergent oils and some do not. Myself I've never used a detergent oil, but then I don't buy a lot of oil anyway. I let my old oil settle the dirt out and pour off the oil as reclaimed, add a bit of zinc to it at the next oil change. I run a continuous cycle of 12 quarts of oil, 4 in the car, 4 out on the shelf for the change and 4 settling. By the time I'm ready to change it again, the 4 that was settling will be settled and the 4 that was on the shelf is what I'll use and the 4 that I drain will be set aside to settle and the whole cycle starts over. Basic oil (non-detergent, no additives) never degrades, it is an organic substance, so all you really do is just pour it right back in once you've removed the impurities from it...I also add 4 oz bottle of ZDDPlus at every oil change.

If you want to keep you engine clean, put an oil filter on it, the one under the transmission door, works pretty good for keep metal particulates out, or you can invest in on of those exterior oil filters that use a modern oil filter cartridge, they also work from what I've seen.

But for flushing an engine, some folks add MMO to the oil to help keep it clean, myself I just don't bother.

[George Andreasen]

I just got a set of wood bands for my engine, and the instructions say to add 4 oz. of Dextron transmission fluid to the oil before using. They must have a good reason...............

[Hal]

I am certainly no expert, but I think the word "Detergent" in the context of motor oil is misleading. What I think is that "Detergent" oils keep impurities suspended so a filter can remove them, and non-"Detergent" oils allow the impurities to settle out and become crud in the crankcase and valve gallery. I do not believe for one instant that using "Detergent" oil is going to miraculously clean all the crud off the inside of a cruddy engine and damage anything. (And I don't believe starting fluid is going to miraculously clean the oil off the cylinder walls and starve the engine for oil, but that's another subject.) Anyway, I think using a detergent oil (Because it is SO much easier to find and in SO many more choices of viscosity) and changing it frequently is the way to go. Yeah, I think it will keep the impurities circulating, but that is why you change it often. I think the way most of us drive our T's, it would take a lifetime to see any difference in longevity from doing it either way. Both have their theoretical advantages and disadvantages. Detergent is the way I choose. Just my opinion which is worth exactly what you paid for it.

[NHUSA]

I just got a set of wood bands for my engine, and the instructions say to add 4 oz. of Dextron transmission fluid to the oil before using. They must have a good reason...............

This is the first time I heard about adding Dextron to the oil with wood bands.
Is it only the first time or at every oil change?

[George Andreasen]

According to the directions the Dextron should be replenished with each oil change, the purpose of which is for smoother band engagement. Dextron does have a mild detergent effect, so it should keep the crud in suspension. The bands/instructions are Jim Guinn's, but through a vendor.

[Charlie B in N.J.]

On your Modern you're asking for nothing but trouble and expense when "flushing" a motor. Especially one that's been properly maintained in the first place. I've experienced, in 2 separate instances, when friends tried it with flush type products. Both broke particles free that lodged in the oil pump pressure valve and locked it open causing a loss of oil pressure. One was a '60's Ford with a removable front cross member so that pan came off in the car. The other was a quite expensive pull the motor fiasco. It's not an intelligent thing to do and can, as stated, only lead to trouble.

[Scott_Conger]

Martynn

My dad had his engine rebuilt in 1975 and for 30 years changed oil religiously every 6 months. The oil was non detergent and always came out looking great. In those years he put about 7000 miles on the car. On his very first tour in Johnson City, TN, he went 8 miles and burned a rod bearing. I pulled the inspection plate and found 1 inch of goop sitting on top of the pan. there were 3 troughs where the rods dipped, with no oil in them. So much for the oil "looking great" when it poured out for oil changes.

I do not know how long you have been using non-detergent oil, but if you pull your pan, you might be surprised what you find.

FWIW.

[James_B_NC]

Scott, when I pull the inspection plate for my T that had been sitting since the 50s to check the inside of the engine (beginning of the restoration) I found all the old oil still sitting in the dips. Only problem was that it had turned into grease...

[Scott_Conger]

James_b

I have experienced the same thing as well

My father's story ended on a $$ but happy note. Never having been on a tour, and then just having been surrounded by 140 Model T's, all buzzing around merrily for a week he lost his fear of driving the thing, and following a rebuild (he wouldn't just replace the rod), he has driven the wheels off his T.

[Ruxstel24]

More modern engines with pressurized oil system, filters, hydraulic lifters, etc. I have flushed numerous times with fair results.

I would avoid it like the plague on a T engine...just my opinion.