Hi, lots of opinions on the subject of engine flushing and oils. There is a risk by using a flush either a branded product, or something like kerosene will dislodge pieces of sludge and block oil passages.

The safer way to clean up the engine is to use a Full Synthetic , at least for a couple oil changes. You’ll find that the oil gets dirty real fast because it’s cleaning up. Lots of stories about synthetic causing leaks, bit of an historical perspective from the early days of synthetic. Not really a problem today. You might see some seeping, but stick it out for a couple 3000 mile oil changes and you’ll see the difference. You can switch back to conventional oil after that, don’t worry about changing back and forth between Dino oil and synthetic, that’s another old mechanics tale.

From a GM service bulletin to dealers a few years ago.....

"General Motors is aware that some companies are marketing tools and equipment
to support engine crankcase flush procedures. GM does NOT endorse or
recommend crankcase flushing for any of its gasoline engines. Analysis of
some of the materials used for crankcase flushing procedures indicates
incompatibility with GM engine components and the potential for damage to some
engine seals and bearings. Damage to engine components resulting from
crankcase flushing procedures is not covered under the terms of the New
Vehicle Warranty."

So...oil and filter changes as per the owner's manual are all you need.

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Son's XC70, daughter's XC60, my 83 244DL, 89 745 (Chev LT-1 V8), and XC60. Also '77 MGB with Chev V6, and four old motorcycles. Long gone: 1981 244, 1994 940 and 1998 S90.

Proper preventive maintenance prevents any need for engine flush.

What symptoms do you encounter now that make you believe you need use of a Kleen Flo 5?

You mean this product:

https://www.kleenflo.com/products/637.html

Are you required to test emissions regular on one of both of your 240s in your province? If yes, do they pass provincial emissions requirements?

Are one are both of the engines basted in engine oil and grime? If yes, probably a clogged PCV system or leaking engine oil seals.

Practice regular oil changes.

Else, I'm unsure how to help you.
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Beh.

This is one of those subjects with a lot of opinions that very wildly, and this is mine: don't use that stuff.

For some reason the 3,000 mi oil change interval remained popular in the USA, perhaps the whole of North America. If you too adhere to that, you're changing the oil 3x more frequently than necessary and IMHO you're basically already flushing the engine on a continual basis.

The official engine oil change interval for the 1992 model year is once a year or every 15,000 km (9,321 mi) whichever comes first. It's half that if the car is run under difficult conditions for long periods of time.

I adhere to the normal 15,000 km interval and I have not yet seen any kind of sludge build-up.

Its likely not doing anything good or bad at same time. Thats why there are lots of these on the market. Its a way to make easy money. Some of these "oil flush" are more expansive than a bottle of 4 litre oil. Go figure.

Doing flushing is good but do it the "proper" way. Use a cheap 4 litre engine oil to replace the current oil in your engine. Continue using the old filter. Drive a short trip to town and back. Then drain the cheap oil. If its still looks "dirty" consider to do second flushing with a fresh cheap oil. Finally use your favourite oil (with filter change) when the drained oil looks "clean"

Do these once every few years if you're really into flushing.


Amarin.