Heat exchanger Flushing

M

mourinor9177

Active member
Joined
May 9, 2019
Messages
27
Fluid Motion Model
R-25 (Outboard)
Hull Identification Number
FMLT2542E424
Vessel Name
Ladyann
Has anyone use vinegar to clean their heat exchanger as a maintenance item? What mixture % did you fine that worked ? 100% vinegar or 50% vinegar to water etc. And how long should it sit in engine before flushing the system ?
I know there are commercial products that can do this but a little nervous on using them as a maintenance item.
My goal is to help the boat run cooler until I pull the boat out for the season and get a full exchanger maintenance done by a professional. Thanks in advance
 
If you have the ability to flush your system when you return Salt Away works well if used regularly. However, as mentioned above, a product like Barnacle Buster or Rid-Lyme are the thing to use. A circulating flush over a period of a couple of hours is the correct way of doing it. I would do the circulating flush probably every three or four years if you are not doing regular Salt Away flushes.
 
Ditto on Barnacle buster. Stuff is great. Anything else is a waste of time .
 
I can't comment on best product to use for cleaning a fouled system. I think everyone points to Barnacle Buster. It has good reviews. I have used Vinegar for a flush to help clean mineral deposits (Not marine growth). 1 gallon vinegar to 3 gallons of hot water in a 5 gallon pail. Pump into the strainer ,impeller removed, and the hose going to the elbow removed and a longer hose connected going to a bucket circulate, let sit . After 1/2 hour reinstall impeller, attach elbow hose, start and run engine up to temperature.

What temperatures are you experiencing?

What is your WOT RPM? What is your temp @ WOT?
What is you high cruise RPM and what is your temp?

What temperatures are you trying to achieve?

I read your last post in this thread viewtopic.php?f=19&t=14292#p94906

That is a good idea because the 1" is marginal at best. Any fouling the raw water cooling can not flow enough to maintain demands of the trans cooler, after cooler and exchanger . Volvo specification is 1 1/4" for the D3 and I think any Fluid Motion powered D3 or Yanmar 2.0L 150 or 180 hp when run hard runs hot. Part is marginal raw water cooling, over propped and fouled raw water system. My temperature has slowly come up because of more equipment on board resulting in over propping. I believe the over propping increases the exhaust temperature. The exhaust manifold is cooled by the close cooling therefor raising the coolant temperature.

If you think your system is fouled I would try the Barnacle Buster. Please post results. That is good information.
 
BB marine":28pzdmlw said:
...I believe the over propping increases the exhaust temperature...
Click to expand...
Engine loading is what dictates exhaust temperature. Having the wrong wheel doesn't mean the engine has to be over loaded. That's an operator decision. Most of us get it in our heads to run the engine at a certain rpm or push the boat at a certain speed and don't adjust for changes in payload, fouling, etc. Back in old school days we only had engine rpm and coolant temperature to go by and didn't know any better. Plus we were (mostly) operating direct driven injection systems. Now we have EFI and more information available like engine load and/or fuel burn rate. If the engine is operated at a constant load(or fuel gph) rather than constant rpm(or heaven forbid boat speed) it will be a lot happier(i.e. behave more predictably). It's true that in extreme cases it may still run hotter at a given load. Coolant pump, raw water pump, and oil pump are all direct drive. So at some point higher load at lower rpm will cause temperatures to climb.

I'm not suggesting that the boat shouldn't be fitted with an appropriately sized wheel. But operating conditions are constantly changing and it is up to the operator to adjust accordingly. If we all operated as suggested there would still be a lot of discussion about inability to make desired boat speed but less about engine/intake/exhaust temperatures running high.
 
Thank you all for the information. For those who asked. My normal cruise speed is 2800 to 3400 RPM around 10 to 14 knots. Before the new strainer design temp was close to 190+ , Now it is at 177 to 184 at my normal rpm. Max throttle is 4100 at 18 knots and temp hits 210 after 1 minute. After i back off it drops very fast back to 190. This is a used boat (2014) some maintenance history is unknown. Had Turbo replace and cooler cleaned under extended warranty (lucky it came with boat).
Plan on doing heat exchanger and replace thermostat at end of season since the boat seems to be running cooler at my normal running speed. If heat stays at or below 185 I would be happy. I only use WOT to get on plane then back off to my normal rpm.
 
My C26 with 220 Volvo operates at 178 F @ 2250 , 180F @ 3200, 183F@ 3400 , 192F @ WOT 3940 rpm to 4130 rpm depending on gear on board. The 210 F is high. The exchanger cleaning sounds like a good idea. Make sure the reverse gear cooler is clear and not fouled. What caused the turbo to fail ?
 
According to mechanic seals leaked most likely getting too hot or poor maintenance. Not sure. Last month of last season found oil on floor. Mechanic found the cooler for turbo was partly clocked and oil in someplace it should not be (he was not clear) . Luckily extended warranty covered it. Thanks for your temp reading so I have something to compare to. Setting up maintenance checklist as I believe the previous owner did not do it well.
 
Martin610":1y63tp0s said:
Ditto on Barnacle buster. Stuff is great. Anything else is a waste of time .
Click to expand...

Yep!
 
mourinor9177":28y8rph6 said:
According to mechanic seals leaked most likely getting too hot or poor maintenance. Not sure. Last month of last season found oil on floor. Mechanic found the cooler for turbo was partly clocked and oil in someplace it should not be (he was not clear) . Luckily extended warranty covered it. Thanks for your temp reading so I have something to compare to. Setting up maintenance checklist as I believe the previous owner did not do it well.
Click to expand...

I had a similar issue with D3 220 hp. I had a oil leak between the turbo and the after cooler. Oil was visible on the stringer and in the bilge. The hose clamps did not hold the silicone hose and it leaked oil. I snugged the hose clamps up but the hose eventually failed. I was anchored at the Bustard islands in the middle of Georgian Bay. I was able to put the damaged hose back on and used 4 clamps to hold it in place so we could get back to Michigan. We had a good weather day and crossed Georgian Bay waited a few days for weather and ran across the North Channel. Volvo service technician claimed the turbo bearing failed. After removing the turbo and inspecting it and then comparing it to the new turbo there was no difference in the bearing. Actually the turbo with 400 hours had less play than the new turbo.

I talked to a Garrett turbo rep ( that is the manufacture of the turbo used on D3's) He said it is not uncommon for them to leak oil past the bearing sleeve when there is little of no boost pressure. Idle up to about 1400rpm. He also said there is no shaft deflection spec, just a endplay spec. He felt the issue was with the hose clamps allowing the hose to leak. I did replace the turbo and pressure checked and cleaned the after cooler. I also changed the hose clamps to a better design clamp.


New turbo ,hose and upgraded hose clamps




Damaged hose

.

I would be interested to find out what actually failed on your turbo to cause the leak. Is there a chance it was coming from the hose ?
 
I will check those clamps. Used Barnicle Buster WOW now the temp is 5 degrees lower at WOT Now the boat is running like it should. 2500 and below at 170-175. 3600-3800 at 180-184 and WOT at 190. The new groco strainer with hose adapter made it very easy to flush it. I will never doubt any of your suggestions again. Thank you all that provided feedback.
 
Update 2023:
It seems that this flushing with Barnicle Buster should be a 1 or 2 year maintenance project. My new Greco stainer with the hose adapter makes it easy to do it. I did find an issue with the Rear gear strainer. When the greco was added the rear gear strainer was not fully checked . Found some seaweed in there and did a back flush Stardboard to port direction with water hose. It did make a big difference. Now as I increase speed the temp raises within the range it should be. I found specs on the d3 thermostat opens at 176 (80 c) and fully at 194 (90 c) so now I see (3 years later) 3250 rpm at 184 3600 at 196-198. I never do WOT except to start a plane for a few seconds.
I normally run at 3250 or at slow speed at 2600. Just make sure your anti freeze tank is totally full.
 
For those who have D3s or D4s with engine pencil zincs do you remove the zincs before flushing. I've read that the Barnacle Buster or similar solutions will dissolve zincs. Thanks.
 
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