Heat Exchanger/intercooler cleaning in-place

[MikeP]

I found that it's time to clean the HE/intercoolers again on our '80 53MY w/8v71TIs. We were out on plane and it only took a couple of minutes at WOT for the eng temps to creep into the mid 190s. At non-planing RPM it holds 165 all day. This is what it was doing some years ago before I pulled/acid-dipped the HE/ICs. After that it would do WOT and the temps never went above 185 regardless of how long the boat was at WOT.

But here's my question...I know that some folks do the acid/flushing without pulling the HE/ICs and I know that Karl posted re this some years ago. I have never done this, opting to remove the components. But this time I'd like to give that a try. For those who have done this with 8v71s, Where did you "break" the system to create the flushing loop? Also, if you can recall, what size PVC fittings did you use to construct it?

 

[SKYCHENEY]

Mike,
I pulled the big hose going to the showerhead and fed the acid mix in there. Then I pulled a hose that comes off close to the RW pump that feeds my stabilizer cooler for the discharge of the mix. If I had not had the fitting there, I would probably have used the zinc fitting on the RW pump for the discharge. It really doesn't matter where you hook it up as long as the fluid passes through the components that you want to clean. Just pull whatever fitting/hose is most convenient.

 

[JLR]

Mike - just be careful. I have done it in a way that isolates the fuel coolers. Each time (three in total) that I did this before I isolated the fuel coolers, I needed to replace the fuel coolers after the acid wash. There must be some sort of solder or something else in the coolers that gets dissolved by the acid causing the coolers to leak after the wash. Although Karl's recirculating way is no doubt better, I simply yank the hose off of one end of the heat exchanger, point it up to the sky, and yank the hose off of the other end of the heat exchanger and put a plug in the tank to block the flow out. I let it sit for a few minutes until the bubbling dies down and then I drain it back into a bucket. That way, only the HE is being hit with the acid. It might be silly to do it this way, but three fuel coolers later, it is my best alternative.

 

[SKYCHENEY]

Mike - just be careful. I have done it in a way that isolates the fuel coolers. Each time (three in total) that I did this before I isolated the fuel coolers, I needed to replace the fuel coolers after the acid wash. There must be some sort of solder or something else in the coolers that gets dissolved by the acid causing the coolers to leak after the wash. Although Karl's recirculating way is no doubt better, I simply yank the hose off of one end of the heat exchanger, point it up to the sky, and yank the hose off of the other end of the heat exchanger and put a plug in the tank to block the flow out. I let it sit for a few minutes until the bubbling dies down and then I drain it back into a bucket. That way, only the HE is being hit with the acid. It might be silly to do it this way, but three fuel coolers later, it is my best alternative.

I don't think you have to worry with diluted Phosphoric acid. I ran mine through for 30 minutes with no problems. What acid did you use, JLR, and at what concentration? Only a few minutes with the phosphoric wouldn't do much.

 

[JLR]

I do not recall to tell you the truth. It may have been muriatic acid. I used one part acid to two parts water.

 

[MikeP]

I have only used muriatic/oxalyic, as per DD for "dipping" and that is what I was planning to use but if there is an issue with the fuel cooler I'll make sure the cooler is bypassed. Heck, might be easier to just pull the HE/ICs like before.

 

[yachtsman12007]

Hi,

I had Chesapeake Descaling Services do mine- Great Job.

 

[rsmith]

How can you make sure she solution is getting all the way up to the top tubes?

 

[MikeP]

Well, I ended up cleaning by pulling the HEs out but if you clean them in place, as long as the bucket of cleaning solution is above the HE/ICs they should fill completely. I was planning to use a 5 gal bucket and a small bilge pump in the bucket to do the pumping once I made up some appropriate fittings. But after messing with the idea a bit, I decided it was just as easy to pull the HE. But I will admit that once you make up the fittings, it's probably pretty simple although I would think it is easier to deal with the whole acid/rinsing thing using the dipping method.

I pulled one IC when I pulled/rebuilt the hydreco pump and that IC was perfectly clean so it is apparent to me that the HE tends to clog for some reason much faster than the ICs. I believe the Zincs on the HE are the reason for some of that. I had quit using zincs in the HE a while back but I recently decided to go back to using ONE zinc in the output side of the HE.

 

[rsmith]

Well, I ended up cleaning by pulling the HEs out but if you clean them in place, as long as the bucket of cleaning solution is above the HE/ICs they should fill completely. I was planning to use a 5 gal bucket and a small bilge pump in the bucket to do the pumping once I made up some appropriate fittings. But after messing with the idea a bit, I decided it was just as easy to pull the HE. But I will admit that once you make up the fittings, it's probably pretty simple although I would think it is easier to deal with the whole acid/rinsing thing using the dipping method.

I pulled one IC when I pulled/rebuilt the hydreco pump and that IC was perfectly clean so it is apparent to me that the HE tends to clog for some reason much faster than the ICs. I believe the Zincs on the HE are the reason for some of that. I had quit using zincs in the HE a while back but I recently decided to go back to using ONE zinc in the output side of the HE.

I'm supprised you get that much scaling in fresh water. How often do you do the cleaning? How's the genny HE?
I dont think the inplace deal is pratical in the Conv. there is no room above the engines. Sometimes I envy you guys with the walk in ER's

 

[REBrueckner]

Mike,
Sky's explanation is what I did...and I had the same 8V71TI's as you. I used Karl's maxiture and pumped it thru my raw water cooling system in the reverse direction from normal flow as suggested. It's also recommend to remove pencil zincs and insert blank plugs while acid washing.

For connections I found some rubber flex couplings in Home Cheapo Plumbing in the vicinity of the PVC that fit over the PVC....I inserted some PVC, probably 2" diameter inside my engine hoses, clamped them, then used the Home Cheapo rubber connection, also clamped, to complete each connection to return hose and bilge pump. Once you have connections selected it's a real easy job and a good time to check zincs at removal also.

In New Rochelle NY near your prior home port after about 8 years since removal by mechanics and cleaning of all components, I barely got any crud out with my own follow up cleaning....it was a preventative one and not really worthwhile in my case.

 

[daniel r morrison]

For over 16 years , at the beginning of each summer I flushed my raw water system on my 671 ti's as follows with no harmful effects and It always brought the temps down 4-7 degrees. I would remove the zinc in the raw water pump and attach a fitting with a piece of clear plastic tube to it, start the engine and siphon a gallon of pure acid through the engine along with the normal sea water, takes about 1 to 2 minutes. Let the engine idle for a while and reinstall new zincs. When I re powered I we looked at the the heat exchangers, as I sold the engines , all was fine

 

[bobk]

If you are going to flush with acid in place, I would suggest not using a muriatic (hydrochloric) acid mix. It's volatile enough to cause unpainted metal to start to rust. I think it also caused nylon tie wraps to fail in my ER. Phosphoric acid will work fine, maybe better with a little oxalic acid added.

Bob

 

[ron6785]

I tried flushing mine in place and sprung some leaks. That was a good thing because turns out to PO when either flushing in place or pulling the HE's did not replace the gasgets but used gasget silicone of some type which the HCA ate up. So I ended up pulling them ,dipping the IC's which is no big deal as you know mike, and replacing all the gasgets and bingo no problem.

 

[gregalves]

Mike - just be careful. I have done it in a way that isolates the fuel coolers. Each time (three in total) that I did this before I isolated the fuel coolers, I needed to replace the fuel coolers after the acid wash. There must be some sort of solder or something else in the coolers that gets dissolved by the acid causing the coolers to leak after the wash. Although Karl's recirculating way is no doubt better, I simply yank the hose off of one end of the heat exchanger, point it up to the sky, and yank the hose off of the other end of the heat exchanger and put a plug in the tank to block the flow out. I let it sit for a few minutes until the bubbling dies down and then I drain it back into a bucket. That way, only the HE is being hit with the acid. It might be silly to do it this way, but three fuel coolers later, it is my best alternative.

I recently had my 8V71 turbos treated with a chemical, flushing out the raw water cooling system. The engine has not run since. It had run fine every week for the last 2 years. Is it possible that the fuel cooler on my engine could spring a leak, due to the chemical cleaning, and for air or water to have gotten into it to the point where it won't start? I've had 2 mechanics look at the boat so far, one gave up, the other got it running for about a half hour after he said he primed the fuel system. Now, he also does not know why it won't start. I had thought it was a contaminated fuel tank, so switched so both engines run off same tank. One engine runs fine, the port one still won't start. I'm guessing it's the fuel cooler, after reading your post. But would it cause the engine to not start, if it was sucking in air/water? Thanks. Greg Alves

 

[davidwigler]

Don't the fuel coolers cool the fuel that is returned to the tank? If so, any water introduced by a failure would be in your tanks and should be detected in your primary filters.

 

[davidwigler]

Sorry, I was looking through some old threads and forgot this was old.

 

[risctaker]

Mike - just be careful. I have done it in a way that isolates the fuel coolers. Each time (three in total) that I did this before I isolated the fuel coolers, I needed to replace the fuel coolers after the acid wash. There must be some sort of solder or something else in the coolers that gets dissolved by the acid causing the coolers to leak after the wash. Although Karl's recirculating way is no doubt better, I simply yank the hose off of one end of the heat exchanger, point it up to the sky, and yank the hose off of the other end of the heat exchanger and put a plug in the tank to block the flow out. I let it sit for a few minutes until the bubbling dies down and then I drain it back into a bucket. That way, only the HE is being hit with the acid. It might be silly to do it this way, but three fuel coolers later, it is my best alternative.

Hi Guys. Picking up on this older thread, I'm ready to do the acid wash n place on my 8V71TI's and after looking at the hoses going into and out of the HE, I'm still trying to figure out how to get those small hose sections (only a few inches long) off the metal tubing. It looks like the small hose sections were placed on the metal tubes first then bolted back (via the flanges) to the HE. How did you guys get these hoses off and, moreover, get new ones back on with out disaassembling the in/out flanges to the HE?? If I have to remove the flanges, I may as well just pull the HE core right out and buy new gaskets?? Input from some who have done this?? Thanks Steve (Risctaker)