Cleaning an engine with HDEO (heavy diesel engine oil)
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  1. #1
    Tadpole
    Join Date
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    Default Cleaning an engine with HDEO (heavy diesel engine oil)

    Hi ,

    I can across this thread while researching engine oil flushing.
    http://www.streetcommodores.com.au/f...ad.php?t=34701

    Basically this guy says
    "HDEO work slowly, as opposed to harsh solvent based engine flush. Put it in your car and let it run in it for a few thousand km, and the detergent package will gradually remove sludge & varnish in your engine. Run a few oil change cycles with them and you will see the difference."
    "HDEO is packed with a more sophisticated detergent package (at a much heavier dose) due to the harsh environment in diesel engine, this gives HDEO the capablity to clear up sludge and varnish in a normal gasoline engine gradually. This clean up action affects varnish/sludge at various seals as well. Thus, causing the false seal to be removed and exposing the real seal, which may be compromised due to previous oil straving. If the seal is compromised, leak is just a problem of time, however, cleaning up and re-exposing the seal to engine oil may give a chance for the seal to be conditioned back to acceptable conditions. However, some off the counter engine flush are simply way too HARSH to most seals, which actually dissolve the seal itself, compare to them, HDEO is a much safer bet in my humble opinion."

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    All sounds quite interesting, but how accurate is it ?

    James.

  2. #2
    Member
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    Adelaide
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    Default

    Checked with a man here who builds race engines. Diesel oil is very popular with those who race Formula Vs as one of its great properties is heat transfer eg. the motor runs cooler. When it comes to street cars, it is a product you can use providing the engine is in perfect conditon, eg less than say 40K. When it comes to high mileage engines, its ability to de-coke an engine is second to none, as its detergents and other additives are agressive in searching out impurities. However, once it has cleaned the engine,and you replace it with your normal oil, you will notice a drop in compression and the engine will start to blow smoke as the carbon which offered compression and sealing qualities is no longer there. His advice is NEVER use diesel oil in a high mileage engine or oil flush products, simply change your oil and filter more often than specified.

  3. #3
    1000+ Posts Wildebeest's Avatar
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    Default Heavy diesel engine oil.

    911,
    Your friends comments on the proper use of diesel engine oil are spot on.
    Phil Irving in his book, Automobile Engine Tuning, mentions this as an alternative to the racing grades.
    My brother in law who raced a 500cc Gold Star BSA in scrambles [now moto cross] always used mono grade diesel oil. As your friend says, engine cooling requires good heat transfer, the oil is important.

    When I bought my first and only new '69 404. I worked in the mines as a diesel fitter, yes I've heard the one liner! The oil used on the Caterpillar loaders was a 30 grade Series 3. I also found that it would fit my 404 perfectly. For the first 50k + this was all it used, along with more than regular filter changes it worked a treat.
    After my time spent in the "bowels of the earth" I had to revert to using a normal type oil. With no detriment.
    To have used the normal oil first and then the diesel grade later could have caused strife by removing the "good" carbon deposits and turning the 404 into an oil burner.

    I have seen the results also of a brand of engine flush additive when put in a very high mileage V6 Volvo. The poor old thing had heavy breathing when you can tell by the smell of the fumes that it is terminal. A smart alec sales man tipped a bottle of this brew into the engine. Voila! A week later it was back with the valve gear sounding like a mariachi band. The flush had loosened of all the carbon and some of it had found its way into the over head gear blocking off the miniscule oil passages in the rockers!

  4. #4
    1000+ Posts
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    Another point to note is that some manufacturers prohibit the use of any engine flush in their engines - Renault with the Sierra being one.


    2003 PEUGEOT 206 GTi

  5. #5
    1000+ Posts
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    Yes, an old mate (well, older) who has been in the business for many years confirmes all of this.
    He uses a Shell diesel oil in all of his cars (about 15). don't remember details.

  6. #6
    1000+ Posts robmac's Avatar
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    Default High Detergent Oils

    Quote Originally Posted by JimB
    Hi ,

    I can across this thread while researching engine oil flushing.
    http://www.streetcommodores.com.au/f...ad.php?t=34701

    Basically this guy says
    "HDEO work slowly, as opposed to harsh solvent based engine flush. Put it in your car and let it run in it for a few thousand km, and the detergent package will gradually remove sludge & varnish in your engine. Run a few oil change cycles with them and you will see the difference."
    "HDEO is packed with a more sophisticated detergent package (at a much heavier dose) due to the harsh environment in diesel engine, this gives HDEO the capablity to clear up sludge and varnish in a normal gasoline engine gradually. This clean up action affects varnish/sludge at various seals as well. Thus, causing the false seal to be removed and exposing the real seal, which may be compromised due to previous oil straving. If the seal is compromised, leak is just a problem of time, however, cleaning up and re-exposing the seal to engine oil may give a chance for the seal to be conditioned back to acceptable conditions. However, some off the counter engine flush are simply way too HARSH to most seals, which actually dissolve the seal itself, compare to them, HDEO is a much safer bet in my humble opinion."

    All sounds quite interesting, but how accurate is it ?

    James.



    I'll vouch for that fact the diesel lubricating oils don't work well in old engines.

    l used Mobil Delvac oil in all my new engines for my 203 rally car - the engines were built for performance rather than longevity. Using Delvac the engines were always very clean inside, especially in oil galleries & easy to re-build.

    However when used in my old 403, the engine became very smokey very quickly. I suspect the Delvac cleaned the carbon deposit off the oil control rings !

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