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Flushing engine with kerosene

A recent Car Talk show recommended flushing the engine with kerosene, and then starting the engine to remove the accumulated gunk. There is a chance it might work, and there is also a chance the engine could seize up. I’m wondering if it would be better to hand-crank the engine 5-10 times, after pouring in the kerosene, then letting it sit overnight to work on the gunk. Hand-crank the engine 5-10 times again the next day. Drain the used kerosene from the oil pan, install a new filter, pour in some lighter weight oil, and run the car for a short time. Drain the oil along with any residual kerosene, and refill with the desired weight of oil. Do you think this will work better at removing the gunk without risking damage to the engine?

I wouldn’t do it, regardless. Anything it’ll clean out probably isn’t doing any harm, and it won’t get out the stuff that’s actually clogging things up. Meanwhile, you might damage some bearings.

Why are you considering doing this?

If the oil is changed regularly there shouldn’t be gunk in the engine. Modern detergent oils hold the dirt particles in suspension so that these particles can be trapped in the oil filter. Even in the old days of non-detergent oils and no oil filter, regular oil changes kept the engine gunk free.

Kerosine. Wonderful. Run the engine with kerosine. That’ll wash out any residue of lubricant that you have on the bearing surfsces, the cylinder walls, and the crank and rod surfaces. You’ll be running the engine completely free of any lubricant. I cannot think of a better way to destroy an engine.

If you hand crank the engine you won’t pump the kerosine through it. That means the engine may survice. Of course, you’ll then be diluting the new oil with the kerosine residue. That’s noty good either.

Where DO these people come up with these ideas? Don’t they understand that the crank and rod surfaces need a good pressurized barrier of nice, thick (relative to kerosine) oil between them? Don’t they realize that a film of oil sticks to the cylinder walls to keep the compression rings from tearing up the walls?

This is NOT similar to cleaning parts in a tray. This is operating the engine after eliminating one of its vital fluids from its wear surfaces. Don’t do this.

I have heard of a local mechanic doing it with transmission fluid, what type or interval I do not recall. The show might have been recorded before the invention of sea foam, there are after market items that address specific issues, what is your issue?

Barky asked an excellent question; what is the issue you’re trying to resolve? Perhaps we can offer some help.