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8v92ta flushing

Discussion in 'Engines' started by ArielM, Feb 26, 2011.

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  1. ArielM

    ArielM Senior Member

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    a few months ago i purchased a 52 hatt with 8v92ta engines. i pulled the zinc out of the heat exchanger and it was obvious there was was some calcium/salt build up in there. Anyhow, i want to flush out the system without disassembling the entire heat exchanger. Now i assume i would get a pump and hook it up the IN of the heat exchanger and have the system flush into a bucket and run this system for 15 min or so but my question is what solution is safe to use? Now i know the detroit manuals says to use a muriatic acid/water on the heat exchanger alone, but what would i use to flush through the engine? will this muriatic acid combo mess up the rubber seals and or impeller? Does anyone make a solution SAFE to use? any input on this would be helpful.
  2. K1W1

    K1W1 Senior Member

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    Hi,

    If you are cleaning the salt water side of a shell and tube heat exchanger you should connect the in and out of the heat exchanger to a pump and re circulate a cleaning solution through the cooler to clean out the crud, you can then drain and flush this mixture out a couple of times before re assembling everything and re starting the engine.

    Muriatic is pretty savage stuff if used incorrectly. You will find if you have a flexible impeller pump that you will not be able to pump much past this as the impeller works like a stop valve pretty well.

    If you want to clean the Fresh Water Side you will need to look for an Automotive type Engine Cooling System Flush solution, or just drain it and flush it out with freshnwater a few times. If you or the previous owners have been up to speed with Jacket Water treatment you should be ok if you are not actually having issues of overheating or finding the Fresh Water Side is full of crud too.
  3. Capt J

    Capt J Senior Member

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    Some companies make a product that you can use to flush out the saltwater side of the heat exchangers, I would bypass the raw water pump if doing it this way. Usually you'll get a small pump and have it drain into a bucket and pump it around for about an hour. I don't recommend using them because they don't do a thorough job IMO. ALSO, most of the overheating problems on a DD (besides a bad impellor) are a result of broken off zincs in the fuel cooler (mainly) and stuck in the heat exchangers as well as other debris (impellor pieces, sometimes even plastic). The descaling stuff and muriatic acid mixture does nothing to remove the more solid stuff or zincs.

    Removing the heat exchangers, fuel cooler, and transmission cooler, on a DD is not that hard of a job and the right way to do it is to take them into a professional place for cleaning and to pressure test them. Also Considering your engine heat exchanger has 2 bundles on an 8v92 (if I remember correctly, 8v71's have 1), and each bundle is about $4000, a transmission cooler on a S+S 8v92 ran $1800 for the part when I needed one about 4 years ago. I wouldn't go playing with muriatic acid. Also I was informed by my cleaning place that professional places don't just use muriatic acid and water, there is another acid mixed in also because just the muriatic and water is a bit too harsh, I forgot the name of the other acid but could make a phone call and get it.

    If you're not overheating on a 5 minute full throttle run, or chewing through raw water impellors at an alarming rate (due to too high of a head pressure), then I would probably leave them alone for the time being.
  4. Capt J

    Capt J Senior Member

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    I would not use an Automotive type engine cooling system flush on a 8v92 as it has rubber o-rings for the cylinder head gaskets and it may eat through them. DD makes a product for flushing the coolant side of the engines on the 92 series. Flushing it with water a couple of times should be ok also. Also I would only use the recommended DD coolant and change it at the recommended interval.
  5. Marmot

    Marmot Senior Member

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    Saf Acid
  6. K1W1

    K1W1 Senior Member

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    Hi,

    Well there boyo it might have escaped your notice that DD's are not made specifically for use in yachts.

    There are or were a lot more in the automotive albeit heavy automotive industry than there will ever be in boats.

    By this I mean Trucks and Buses.

    It might also surprise you to know that DD are not the only manufacturer who uses wet liners and has rubber O Rings at either end of the water jacket.

    The last time I had a DD in bits I do not remember the Fire Ring on top of the liner being made of rubber.

    There was if I recall correctly a square section rubber piece that fitted into a groove around the outer edge of the block.

    Currently we are being encouraged to use Citirc Acid to clean Heat Exchangers over this side of the pond by our HE Manufacturers as they have a plastic liner on the inlet end that can be damaged by other acids.
  7. Capt J

    Capt J Senior Member

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    Whichever the case may be, the Detroit Diesel dealer told me specifically not to use anything other then the Detroit Diesel (power flush I think it is/was called) or water to flush the freshwater side out as the automotive stuff has too high of a PH and can damage the rubber O-rings. Considering DD makes a product specifically for that purpose and for those engines, why would you risk using something from your local auto parts store to flush out an engine that costs over $20,000 to rebuild?
  8. dennismc

    dennismc Senior Member

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    Flushing

    Do not forget that some Countries have citizens with so much money, they ignore Mfr's data...more fun..greater risk..big rush... lol..
  9. dennismc

    dennismc Senior Member

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    8 v 92 flushing

    sure liked that "boyo" reference...not heard that since the late 50's in Ireland

    omg just dated myself.!!!
  10. K1W1

    K1W1 Senior Member

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    Hi,

    Was he next to the CAT Dealer who told you about the secret break in oil you write so much about a while ago?

    Do you think if you were an agent for something and had things that carried the same label that you would try to sell them first?

    DD and CAT and the other manufacturers do not generally make all these treatment systems themselves, they have it made and packaged for them but the actual contents does not vary much by brand if the specs are the same.
  11. Capt J

    Capt J Senior Member

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    The 1 thing I know is that you cannot go wrong using the engine manufacturers product that they sell for their engine. Whether they make it or not, they have tested what they are branding and approve of it's use on their engines. Versus other things that may or may not be snake oil, or a good product.

    I also know that DD has a few different types of coolant for the various
    engines, not 1 coolant for all. I had a warranty issue with a set of under 2 year old and 250hr Series 60 MTU/DD's. Both aftercoolers were leaking as was the gaskets on the side of the block on the intake manifold. The first thing the dealer did was asked who serviced the engines, what type of oil and coolant was used in them, and they then did oil samples and coolant samples BEFORE DD/MTU authorized the warranty repairs. They stated specifically if it wasn't DD coolant (I think the DD G92 it's called), the job wasn't covered. The dealer did all of the servicing at proper intervals so it was not a problem, but would've been.

    DD recommends I think it's the PowerCool 2000 reddish pink coolant for the 92 series, and only that coolant. I've seen a Captain use the same coolant on 2 Westerbeke generators. It ate through the thermostat housings, freshwater pump housings and a few other parts on both Westerbeke generators in about a years time. The owner was very unhappy about this because they had extended warranties at the time and were not covered by Westerbeke.

    Cummins and Onan also use their own coolant, that blue stuff. If they felt one type was better then the other, they'd probably sell it or endorse it.

    With the price of a rebuild on a Marine Diesel, why skimp and save a few bucks using something other then the dealer branded stuff? I could see in an emergency, but why otherwise take the chance? Besides, when a potential buyer comes on the boat and see's factory oil filters, fuel filters, oil and coolant they have better piece of mind rather then seeing a Napa or fram oil filter, fuel filters etc.......even though the Napa gold and Baldwin are good filters.

    Sometimes manufacturers do push a certain product for longevity reasons. For example when The Corvette came out with the LT-1 motor in 2002, and all subsequent corvettes, they have specified Mobil 1 oil. The reason for that was conventional oil, got way too hot in that particular vehicle, broke down prematurely, and the only other remedy was to mount an external oil cooler or specify Mobil 1 synthetic. Using conventional oil, will void your engine warranty in that car, period.
  12. Davidoc

    Davidoc Senior Member

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    Hey Capt. J,

    I had started a thread on this subject over on the Post Marine thread. I searched for similar discussions and found this one. I like your point of view on the subject and wondered if you still feel the same or has anything else developed since you wrote this? Thanks for posting of your experience on these forums. My 6v92's are creeping up in temp at 1850 RPM a few degrees over 180 now and I want to take care of it now. The exchangers are due and I think I will pull the coolers and see if anything is stuck it the intakes. I was then hoping to flush them good and see how they run. I haven't done this maintenance for several years but she has low annual hours on her and I stay on top of the coolant quality with the Detroit test strips and the impellers. Havent had a broken one in years. The big zincs, on the raw water intakes in the exchangers, do run down but I change them early. Any other comments would be appreciated over on the Post Engine Flush thread or this one.
    Thanks again,
    David
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