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Old 05-14-2001, 11:06 PM
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Just finished reading the 4 page motor oil thread. WOW!! This brings up a question for me. What is the feeling about
using a "Motor Flush" type product? You know, the stuff you pour into the crankcase via the oil fillercap.......and then idle for 10 minutes or so and drain. The idea being to clean engine deposits. Is this a good or bad thing?

Swamp me with opinions.

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Old 05-14-2001, 11:28 PM
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I'd say bad idea. Stick with regular hot oil changes and you'll be plenty clean inside.

I have no history on my car before my purchase of it. I do know, after having pulled the valve covers, that it was at least subjected to regular oil changes. How? There wasn't any crud or sludge built up on the top of the head, timing chain guides and sprockets looked great for their age too. Don't know if the chain had been replaced at any time, but it looked to be in good shape too.
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Old 05-15-2001, 07:50 AM
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I agree with Mike, with one exception. If the engine is really cruddy, go ahead and use the flush. Only use the quart that you add, idle ten minutes then drain. I would see that the engine is at operating temperature before adding the flush.

If it's not crudded up too bad, I would do hot oil and filter changes about every 500 miles until it is all cleaned out, that's the safest way.

The flushing that you definitely want to stay away from is cranking the engine with nothing but solvent in the crankcase.

After you have the engine clean, then start religiously performing hot, frequent, oil and filter changes.

As Mike said, this is the best way to clean the engine.

Change oil hot and change oil often,
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Old 05-15-2001, 08:42 AM
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Thank you Mike, thank you Larry. "Hot and Often" it is!
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Old 05-15-2001, 08:02 PM
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The other possible problem with using Motor Flush is that what ever crud it doesn't dislodgr, it will loosen up a bit. Then it may come loose after you have filled up with new oil and start driving. So you could have little bits of crud flowing around and and could plug up passages. As Larry's infamous saying goes, "change it HOT and often".
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Old 05-16-2001, 02:26 AM
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With 293,000 miles on my engine (87 300D Turbo), it was very dirty inside even though it had regular oil changes. Even though my compression is pretty good, we found some oil in the prechamber of #6 when replacing injectors. I've been smoking at startup and at idle.

My mechanic says that if we replace the valve seals without the replacing the guides, they won't last very long. Even if I could afford a valve job right now (which I can't) he is afraid that at this point in the engine's life with high mileage, I'd end up having to come back for rings and or more. Probably time for a complete rebuild.

In order to put off any major expenditures, we put a can of flush, (expensive stuff with a green label in German), and ran it for about 400 miles to try to loosen up whatever we could from the valves. Drained and changed the oil, I've changed it a couple of times.

With the regular usage of Redline DFC, my car seems to smoke less and run smoother. We put a plate between the EGR valve and the intake to reduce the oil.

I've done about all I can without major mechanical work for the time being. The only problem I've had since the oil flush which may or may not be related (I have a hunch the flush may have aggravated the situation) was that I had to replace the diaphragm in the injector pump so that the engine would shut off with the key.

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Old 05-16-2001, 08:53 AM
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That's one of the good things about a diesel. When it gets tired, and using oil, it doesn't foul plugs, or burn valves, and other ills like a gas engine. With a diesel you can drive it to the point at which it uses so much oil that you can't carry enough with you to get where you're going.

Good luck,
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Old 05-17-2001, 01:01 AM
Jason M.
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Oil Flushes

I saw the bottom end of a camaro whos owner used a can of "motor flush" when it was pretty gummed up. It loosened the sludge and varnish alright.... right into the crankcase, plugged the Oil pump's screen and all but stopped oil flow.... The engine seized.. I wouldn't use the stuff.

A friendly warning from your pal,

Jason M.
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Old 05-17-2001, 05:41 AM
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The Camaro must have been REALLY ignored for it to be THAT bad. I suppose if one had been neglected that bad, I wouldn't vote for the motor flush either. 100 mile hot oil changes for a while would be the key if it were that bad.

I have used the flush a few times, but it was in an engine that was just a little dirty, not completely caked like the engines with Amalie or Havoline in the sixties used to get.

Have a great day,
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