I looked in the archives but couldn't find anything that specifically deals with how you clean a heat exchanger from a diesel motor (Universal). I saw one or two posts that refer to having it boiled out at a radiator shop. Is this the best thing? Can I rod it out with a piece of heavy insulated wire? Should I do this in addition to having it boiled out? Instead of? Something else? Thanks.
cleaning heat exchange
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Heat exchanger
Hi John; I just did the job on my Universal M25XP. Very easy job. I only did the fresh water portion. Remove the two end caps being careful not to mess up the rubber gaskets. Took a small long handled brush and ran it thru the tubes, and then flushed with a hose at moderate pressure. Cleaned up nice, and only found a few small chunks of an old impeller, nothing big. Be careful not to over tighten the end caps, just enough so they don't leak. If you want to do the internal engine side, I would proceed just like flushing a cooling system on an automobile. I like the Prestone products. Flushed mine out when I first got the boat, and fluid has been clean and green ever since. I change the antifreeze about every 3 years. fair winds Dave
Hi John; I just did the job on my Universal M25XP. Very easy job. I only did the fresh water portion. Remove the two end caps being careful not to mess up the rubber gaskets. Took a small long handled brush and ran it thru the tubes, and then flushed with a hose at moderate pressure. Cleaned up nice, and only found a few small chunks of an old impeller, nothing big. Be careful not to over tighten the end caps, just enough so they don't leak. If you want to do the internal engine side, I would proceed just like flushing a cooling system on an automobile. I like the Prestone products. Flushed mine out when I first got the boat, and fluid has been clean and green ever since. I change the antifreeze about every 3 years. fair winds Dave
Use a commercial 'boiler descaler'
... such as Marsolve (marsolve.com) or Rydlyme (www.rydlyme.com). Such chemicals wont dissolve the base metal of the exchanger nor the downstream passages in the exhaust manifold (which usually get MORE fouled than the ht. exchanger). The Prestolite chemicals are for the little bit of fouling that forms in a closed loop system such as an automotive radiator. Raw (salt) water is 'loaded' with carbonates which easily come out of solution and form thick scale if the raw (fresh OR salt) water gets above ~145 degrees F.; hence the need to 'pickle' both the exchanger AND the exhaust manifold. Acids (such as muriatic, etc.) will 'keep on going' through the scale and into the base metal of the engine, the above compounds are much 'easier' on the engine; plus, they dont need any 'special neutralization' (for acids) as they are 'bio-degradeable'. Since these chemicals dont penetrate down through the black/blue (ferrous) rust which is protective to cast iron, the engine internals will last much longer. Its internal corrosion that 'kills' a marine engine. To best apply such chemicals run a 'loop' from bucket-full of chemicals to the pump, through the exchanger all the way through & past the manifold (break the connection there) and back to the bucket. Drain the raw water out first, then load with chemicals, then let soak. Sure you can rod-out an exchanger (if the raw water is on the 'inside' of the tubes).... but you cant rod-out the exhaust manifold, the manifold should be cleaned out as often (or more often) as the heat exchanger. The exchanger for an MD11 (the 'pisser') is so light weight that it probably should be taken to a radiator shop and cleaned out by ultrasonic methods. ;-)
... such as Marsolve (marsolve.com) or Rydlyme (www.rydlyme.com). Such chemicals wont dissolve the base metal of the exchanger nor the downstream passages in the exhaust manifold (which usually get MORE fouled than the ht. exchanger). The Prestolite chemicals are for the little bit of fouling that forms in a closed loop system such as an automotive radiator. Raw (salt) water is 'loaded' with carbonates which easily come out of solution and form thick scale if the raw (fresh OR salt) water gets above ~145 degrees F.; hence the need to 'pickle' both the exchanger AND the exhaust manifold. Acids (such as muriatic, etc.) will 'keep on going' through the scale and into the base metal of the engine, the above compounds are much 'easier' on the engine; plus, they dont need any 'special neutralization' (for acids) as they are 'bio-degradeable'. Since these chemicals dont penetrate down through the black/blue (ferrous) rust which is protective to cast iron, the engine internals will last much longer. Its internal corrosion that 'kills' a marine engine. To best apply such chemicals run a 'loop' from bucket-full of chemicals to the pump, through the exchanger all the way through & past the manifold (break the connection there) and back to the bucket. Drain the raw water out first, then load with chemicals, then let soak. Sure you can rod-out an exchanger (if the raw water is on the 'inside' of the tubes).... but you cant rod-out the exhaust manifold, the manifold should be cleaned out as often (or more often) as the heat exchanger. The exchanger for an MD11 (the 'pisser') is so light weight that it probably should be taken to a radiator shop and cleaned out by ultrasonic methods. ;-)
Salt water?
Hi Rich; Thanks for jumping in. I am a fresh water sailor and we tend to forget the "ravages" of salt water. Your advice makes much more sense for a salt water environment, and the OP is from California. (Everytime I see a salt water boat, I give thanks that I sail on the Great Lakes!;-))) Fair winds Dave
Hi Rich; Thanks for jumping in. I am a fresh water sailor and we tend to forget the "ravages" of salt water. Your advice makes much more sense for a salt water environment, and the OP is from California. (Everytime I see a salt water boat, I give thanks that I sail on the Great Lakes!;-))) Fair winds Dave
Maybe this'll work for you;
On my Yanmar just remove the nearside end cap from the exchanger. With a standard set of drill bits find the ID of the tubes. (insert bits shank-first until the largest that fits is found) Then go to your local Home Depot, or hardware store for a long bit, the same size. (the long ones are used by electricians) Then chuck it up in your drill and power-up. It's good to have a marker on the bit to limit travel but the rear end cap will do the same thing. Result; no more calcification. You don't even have to flush the exchanger. The crud just goes overboard with the cooling water.
On my Yanmar just remove the nearside end cap from the exchanger. With a standard set of drill bits find the ID of the tubes. (insert bits shank-first until the largest that fits is found) Then go to your local Home Depot, or hardware store for a long bit, the same size. (the long ones are used by electricians) Then chuck it up in your drill and power-up. It's good to have a marker on the bit to limit travel but the rear end cap will do the same thing. Result; no more calcification. You don't even have to flush the exchanger. The crud just goes overboard with the cooling water.
Another suggestion
John, I have also found that it is not necessarily the tubes that cake up, but rather the inlet and outlet ports for the salt water. Deposits form inside the ports connecting to the hoses from the raw water pump and to the muffler. My old 2 inch HX was notorious for this and I've found some evidence of it on our newer 3 inch HX. So before you go blasting away at the tubes, if you clean it as suggested in the link in my last post, also be sure the check the ports, too. Remember, the water inside the tubes is the fresh water, which is circulated at a good velocity inside the tubes. Anything that "drops out" of any cooling water would more likely be from the raw (salt) water side in the shell. Also, after cleaning, shake it. If it sounds like a mariachi band then there's still something inside that needs to be removed, most likely the bits and pieces of a decomposing zinc. We have to change our zincs anywhere from three to five months in our marina right down the estuary from you.
John, I have also found that it is not necessarily the tubes that cake up, but rather the inlet and outlet ports for the salt water. Deposits form inside the ports connecting to the hoses from the raw water pump and to the muffler. My old 2 inch HX was notorious for this and I've found some evidence of it on our newer 3 inch HX. So before you go blasting away at the tubes, if you clean it as suggested in the link in my last post, also be sure the check the ports, too. Remember, the water inside the tubes is the fresh water, which is circulated at a good velocity inside the tubes. Anything that "drops out" of any cooling water would more likely be from the raw (salt) water side in the shell. Also, after cleaning, shake it. If it sounds like a mariachi band then there's still something inside that needs to be removed, most likely the bits and pieces of a decomposing zinc. We have to change our zincs anywhere from three to five months in our marina right down the estuary from you.
my plan
Okay, so here's what I'm planning: As far as using a drill bit to clean out the tubes: It's been suggested to me that it's best NOT to put any metal object through those tubes. So I was thinking of getting a piece of insulated wire of the right size (maybe #10 or so?) to run down there. Either that or see if I can find a very small diameter bottle brush to use. What do those who have used a bit think of this? Then, I just ordered some "Rydlyme" and I'll soak the head exchanger in a bucket of that. Then, after recleaning the tubes, reinstall the exchanger, fill up again with coolant (it almost all ran out), and then run the rydlyme through the system, shutting off the motor and letting it sit in the system for an hour or so before flushing it althogether. Two questions: 1)From what I've read, if I'm not careful I'll get airlock in the system. If I put coolant in the system through the cap on the engine, will that prevent it? 2)My understanding is that the fact that my boat is in salt water is a major contributor to problems. I was thinking of putting a y-valve on the raw water intake hose and every time after I run the motor flush it with a bucket of fresh water so that salt water doesn't sit in the engine. The reason for the y-valve is just to make it easier to flush it. Does this sound like it's something that would be worthwhile?
Okay, so here's what I'm planning: As far as using a drill bit to clean out the tubes: It's been suggested to me that it's best NOT to put any metal object through those tubes. So I was thinking of getting a piece of insulated wire of the right size (maybe #10 or so?) to run down there. Either that or see if I can find a very small diameter bottle brush to use. What do those who have used a bit think of this? Then, I just ordered some "Rydlyme" and I'll soak the head exchanger in a bucket of that. Then, after recleaning the tubes, reinstall the exchanger, fill up again with coolant (it almost all ran out), and then run the rydlyme through the system, shutting off the motor and letting it sit in the system for an hour or so before flushing it althogether. Two questions: 1)From what I've read, if I'm not careful I'll get airlock in the system. If I put coolant in the system through the cap on the engine, will that prevent it? 2)My understanding is that the fact that my boat is in salt water is a major contributor to problems. I was thinking of putting a y-valve on the raw water intake hose and every time after I run the motor flush it with a bucket of fresh water so that salt water doesn't sit in the engine. The reason for the y-valve is just to make it easier to flush it. Does this sound like it's something that would be worthwhile?
Your ideas
John: 1)From what I've read, if I'm not careful I'll get airlock in the system. If I put coolant in the system through the cap on the engine, will that prevent it? The airlock is in the freshwater system from the hoses from and back to the thermostat from the hot water heater. It's called "burping" and there are two ways to do this: run the engine, experience extremely high temperature and crack open the little valve on the top of the thermostat while revving the engine (not recommended); or, either disconnect one hose from the base of the thermostat and use a Jabsco Par hand pump to assure that the water line from the thermostat to the heater is full OR just disconnect one of the two hoses at the thermostat and pour water (distilled) into it to assure that the air "bubble" is gone. I do that latter, it's the easiest. You can use our C34 message board and do a search on "burp." No beer stories, I promise.
2)My understanding is that the fact that my boat is in salt water is a major contributor to problems. I was thinking of putting a y-valve on the raw water intake hose and every time after I run the motor flush it with a bucket of fresh water so that salt water doesn't sit in the engine. The reason for the y-valve is just to make it easier to flush it. Does this sound like it's something that would be worthwhile? With all due respect, nonsense! The salt water DOES NOT sit in the engine, that's why you have a fresh water cooled system. The salt (raw) water is explained in your engine operating manual, which is available on your C36 website and ours, too. It goes from the inlet, thru the strainer, to the RW pump to the heat exchanger, thru the exhaust riser nipple and out via the muffler. You do not need to even consider this.
John: 1)From what I've read, if I'm not careful I'll get airlock in the system. If I put coolant in the system through the cap on the engine, will that prevent it? The airlock is in the freshwater system from the hoses from and back to the thermostat from the hot water heater. It's called "burping" and there are two ways to do this: run the engine, experience extremely high temperature and crack open the little valve on the top of the thermostat while revving the engine (not recommended); or, either disconnect one hose from the base of the thermostat and use a Jabsco Par hand pump to assure that the water line from the thermostat to the heater is full OR just disconnect one of the two hoses at the thermostat and pour water (distilled) into it to assure that the air "bubble" is gone. I do that latter, it's the easiest. You can use our C34 message board and do a search on "burp." No beer stories, I promise.
2)My understanding is that the fact that my boat is in salt water is a major contributor to problems. I was thinking of putting a y-valve on the raw water intake hose and every time after I run the motor flush it with a bucket of fresh water so that salt water doesn't sit in the engine. The reason for the y-valve is just to make it easier to flush it. Does this sound like it's something that would be worthwhile? With all due respect, nonsense! The salt water DOES NOT sit in the engine, that's why you have a fresh water cooled system. The salt (raw) water is explained in your engine operating manual, which is available on your C36 website and ours, too. It goes from the inlet, thru the strainer, to the RW pump to the heat exchanger, thru the exhaust riser nipple and out via the muffler. You do not need to even consider this.bad phrasing
Sorry, I phrased it incorrectly. I shouldn't have said that the salt water sits in the engine. I should have said in the heat exchange and the hoses leading to and from it. The reason I asked about this is that I read somewhere about someone who periodically flushes this out by running the engine with the intake hose in a bucket of fresh water. Can I take it that this is not necessary?
Sorry, I phrased it incorrectly. I shouldn't have said that the salt water sits in the engine. I should have said in the heat exchange and the hoses leading to and from it. The reason I asked about this is that I read somewhere about someone who periodically flushes this out by running the engine with the intake hose in a bucket of fresh water. Can I take it that this is not necessary?
heat exchanger tubes
can be cleaned with the correctly sized gun barrel wire brush cleaner Available in most sports stores. Wal Mart used to sell (still may ?) Cost is less then $10 with a handle and rod, just make sure you are sized correctly (alot of the brushes are in metric) Good Luck !
can be cleaned with the correctly sized gun barrel wire brush cleaner Available in most sports stores. Wal Mart used to sell (still may ?) Cost is less then $10 with a handle and rod, just make sure you are sized correctly (alot of the brushes are in metric) Good Luck !
Yes, John, it is NOT necessary
That's what the HX is for. The salt water sits in the HX, ity's there all the time, engine running or not. The flushing you're talking about is for winterizing, which we, thank goodness and our climate, do not have to do.
That's what the HX is for. The salt water sits in the HX, ity's there all the time, engine running or not. The flushing you're talking about is for winterizing, which we, thank goodness and our climate, do not have to do.
Rod it
For less than 2 bucks Home depot will provide a piece of threaded rod about the length and diameter of the exchanger tubes . I just did this on the 3" Heat X on the Universal 25XP. Run the rod in and out. Forget about the old Radiator Shops and a boil out. The EPA has closed them down, at least in MA and RI. It is easier to flush the coolant side with a prestone flush product while doing the block, heat riser and full cicuit.
For less than 2 bucks Home depot will provide a piece of threaded rod about the length and diameter of the exchanger tubes . I just did this on the 3" Heat X on the Universal 25XP. Run the rod in and out. Forget about the old Radiator Shops and a boil out. The EPA has closed them down, at least in MA and RI. It is easier to flush the coolant side with a prestone flush product while doing the block, heat riser and full cicuit.
Ya know,,,,,,
No matter what you are told, someone will recommend against it or have a better way. Ah, the internet. Of course, in the old days we used trial and error.
No matter what you are told, someone will recommend against it or have a better way. Ah, the internet. Of course, in the old days we used trial and error.
Dave from Mi.....
You get the same effect of carbonate fouling in salt water as in fresh water .... its just that salt water has a much higher concentration of dissolved carbonates thus needs more frequent descaling than in 'fresh' water. Take ANY raw water, raise it over ~145 deg. F and boiler scale will begin to form on the 'hot metal' .... just takes longer to build up when in 'fresh' water than in salt water. This is how 'rocks' are formed, your teapot/coffeemaker fouls ..... or your engine fouls. Its simply taking ANY raw water and heating it over that 'magic' ~145 degrees F. !!!!!!!! ;-)
You get the same effect of carbonate fouling in salt water as in fresh water .... its just that salt water has a much higher concentration of dissolved carbonates thus needs more frequent descaling than in 'fresh' water. Take ANY raw water, raise it over ~145 deg. F and boiler scale will begin to form on the 'hot metal' .... just takes longer to build up when in 'fresh' water than in salt water. This is how 'rocks' are formed, your teapot/coffeemaker fouls ..... or your engine fouls. Its simply taking ANY raw water and heating it over that 'magic' ~145 degrees F. !!!!!!!! ;-)
Here we go again!
I ordered the "Rydlyme" that was recommended by one person on this thread. I also see that somebody else is recommending that I flush out the coolant side. I hadn't thought about that. Is this the common practice? I'm a little nervous about using a metal rod to clean out the tubes, so I'll look for a brush at a gun shop, as was recommended here. If not, then I'll get a piece of insulated wire (maybe #12 or 10?) and use it.
I ordered the "Rydlyme" that was recommended by one person on this thread. I also see that somebody else is recommending that I flush out the coolant side. I hadn't thought about that. Is this the common practice? I'm a little nervous about using a metal rod to clean out the tubes, so I'll look for a brush at a gun shop, as was recommended here. If not, then I'll get a piece of insulated wire (maybe #12 or 10?) and use it.
Fresh water
HI Rich H. Thanks for the reply. I understand what you are saying. When I did my HX this spring, I only did the sea water portion, and there was little or no scale in the tubes for that portion. Engine has approx. 400 hours since new in 1996. I have flushed the "internal" engine cooling system with the Prestone flush product, and very little "crap" came out of entire system, so I think I am in good shape. Engine Temp. gauge rarely gets over 160F. fair winds Dave
HI Rich H. Thanks for the reply. I understand what you are saying. When I did my HX this spring, I only did the sea water portion, and there was little or no scale in the tubes for that portion. Engine has approx. 400 hours since new in 1996. I have flushed the "internal" engine cooling system with the Prestone flush product, and very little "crap" came out of entire system, so I think I am in good shape. Engine Temp. gauge rarely gets over 160F. fair winds Dave
No reason whatever to clean out the 'fresh' side..
The fresh water side is a closed loop with no additional water being constantly added; the wee bit of carbonates in that water will quickly drop out (with VERY thin/minimal fouling) and that the 'side' will become stable. In heat exchangers such 'normal' fouling is usually calculated into the 'heat balance' equations and is taken care of by the amount of extra surface area of tube area selected. You have to remember that the tubes in 'engine' heat exchangers use extremely thin walled tubes that are 'rolled' (rotary pressed) into their tubesheets ... dont have extra 'corrosion allowance' to take care of much 'corrosion/erosion'; so 'rodding out' such exchangers can easily promote tube leaks if you're not VERY careful when 'rodding'. When cleaning out the fresh/closed loop side you usually have to refill with new water ... and the system will exactly equilibrate to the same level of fouling immediately - so why bother?
The fresh water side is a closed loop with no additional water being constantly added; the wee bit of carbonates in that water will quickly drop out (with VERY thin/minimal fouling) and that the 'side' will become stable. In heat exchangers such 'normal' fouling is usually calculated into the 'heat balance' equations and is taken care of by the amount of extra surface area of tube area selected. You have to remember that the tubes in 'engine' heat exchangers use extremely thin walled tubes that are 'rolled' (rotary pressed) into their tubesheets ... dont have extra 'corrosion allowance' to take care of much 'corrosion/erosion'; so 'rodding out' such exchangers can easily promote tube leaks if you're not VERY careful when 'rodding'. When cleaning out the fresh/closed loop side you usually have to refill with new water ... and the system will exactly equilibrate to the same level of fouling immediately - so why bother?
A couple of years ago
I did some research and bought some Marsolve or Rydlyme to do the same thing and ended up removing the cap and using an electricians snake with a slite bend I scraped the tubes out, there wasn't much crap inside and the product I bought still sits on the shelf of my boat dept work shop and the HX has great flow and stays cool. BTW some gal from the company emailed me and wanted to know what I thought of the product and I was impressed with the follow up so I'd guess the stuff works
I did some research and bought some Marsolve or Rydlyme to do the same thing and ended up removing the cap and using an electricians snake with a slite bend I scraped the tubes out, there wasn't much crap inside and the product I bought still sits on the shelf of my boat dept work shop and the HX has great flow and stays cool. BTW some gal from the company emailed me and wanted to know what I thought of the product and I was impressed with the follow up so I'd guess the stuff works
Muriatic Acid
My engine would run a little hot in high RPM's and we tried to get a marine mechanic to clean out the heat exchanger. He was too busy but told us how to do it. I AM NOT A MECHANIC SO I DONT REMEMBER EXACTLY WHAT WE DID, BUT HERE GOES..... 1) Disconnect hose from heat exchanger to the sea strainer at the sea strainer end. 2) Make an extension hose from the heat exchanger end to somewhere outside the boat or on the open deck. You do NOT want to be in an enclosed area when you do this or you will probably die from the fumes.THIS IS NOT A JOKE. 3) Have 5 gallons of muriatic acid handy and a clean 5 gallon bucket. 4) Pour 3 gallons of acid into the bucket and drop the hose end into it. 5) Start your engine and as the 3 galllons are are being sucked out of the bucket, add the other 2 gallons. Dont get splashed!!!!! be careful and methodical. 6) Just as the last of the acid is about to run out, shut off the engine. Your entire heat exchanger system, hoses and all now have muriatic in them. 7) After a period of no more than 5 minutes, start your engine again and fill bucket with clean water from a garden hose and let run for a few minutes and watch the crap come out of your exhaust. When looking clean, shut off engine. 8) Carefully replace the hose back on the sea strainer and tighten it up. 9) Let engine run for about 30 minutes and the system will be completely flushed free of acid. And thats all there is to it. WARNING: 1) THIS IS POTENTIALLY DANGEROUS AND A DEFINATE HEALTH RISK TO LUNGS, EYES AND BRAIN. THIS IS A TWO MAN JOB. Plan it out first so that both of you know exactly what to do and when. DO NOT RUSH. 2) Do not let muriatic acid sit in your system for more than 5 minutes. That should be plenty of time to disconnect the temporary hoses and replace the original back on the sea strainer. 3) This will probably eat up any zincs that you may have on your heat exchanger, so have new ones handy. 4) See if you can get Nice'n'Easy on here, he is a good mechanic and will probably remember this better than I do. Tony B
My engine would run a little hot in high RPM's and we tried to get a marine mechanic to clean out the heat exchanger. He was too busy but told us how to do it. I AM NOT A MECHANIC SO I DONT REMEMBER EXACTLY WHAT WE DID, BUT HERE GOES..... 1) Disconnect hose from heat exchanger to the sea strainer at the sea strainer end. 2) Make an extension hose from the heat exchanger end to somewhere outside the boat or on the open deck. You do NOT want to be in an enclosed area when you do this or you will probably die from the fumes.THIS IS NOT A JOKE. 3) Have 5 gallons of muriatic acid handy and a clean 5 gallon bucket. 4) Pour 3 gallons of acid into the bucket and drop the hose end into it. 5) Start your engine and as the 3 galllons are are being sucked out of the bucket, add the other 2 gallons. Dont get splashed!!!!! be careful and methodical. 6) Just as the last of the acid is about to run out, shut off the engine. Your entire heat exchanger system, hoses and all now have muriatic in them. 7) After a period of no more than 5 minutes, start your engine again and fill bucket with clean water from a garden hose and let run for a few minutes and watch the crap come out of your exhaust. When looking clean, shut off engine. 8) Carefully replace the hose back on the sea strainer and tighten it up. 9) Let engine run for about 30 minutes and the system will be completely flushed free of acid. And thats all there is to it. WARNING: 1) THIS IS POTENTIALLY DANGEROUS AND A DEFINATE HEALTH RISK TO LUNGS, EYES AND BRAIN. THIS IS A TWO MAN JOB. Plan it out first so that both of you know exactly what to do and when. DO NOT RUSH. 2) Do not let muriatic acid sit in your system for more than 5 minutes. That should be plenty of time to disconnect the temporary hoses and replace the original back on the sea strainer. 3) This will probably eat up any zincs that you may have on your heat exchanger, so have new ones handy. 4) See if you can get Nice'n'Easy on here, he is a good mechanic and will probably remember this better than I do. Tony B
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