Diesel engine fresh water flushing - Does anyone bother?

[benchmark]

Many of my friends fush their outboard petrol engines with fresh water after every use in saltwater.

My engine - volvo 2030 with raw water, heat exchanger and fresh water 'internal' cooling. Would I help extend the life of my engine if I fitted a Y valve to the raw water intake before the pump so that I could hook up a fresh water hose and flush out the salt every now and then? I understand that the outboards need it more as they are entirely salt water cooled but I thought that by flushing I could help my engine last longer.

Has anyone tries this? Is it worth it? or am I being over protective of my pride and joy?? PS my boat is in arabian gulf so very salty!

Short answer, nope

 

[swampy396]

I have recently bought a Santana 28 with no indication of hours run on the diesel. I would like to flush the raw water system to give me a starting point. Can I use automotive radiator flush to remove any possible buildup of calcium in the system?

 

[mbroom]

Small outboards have tiny water passages that block very easily, in addition they are usually alloy which can corrode in salt water.

 

[Tim Good]

I have recently bought a Santana 28 with no indication of hours run on the diesel. I would like to flush the raw water system to give me a starting point. Can I use automotive radiator flush to remove any possible buildup of calcium in the system?

I can't see any reason not to use normal radiator flush. It no sure a raw sea water system would have calcium build up. Perhaps the fresh water closed loop might. Additionally the impeller in the raw circuit might not like the engine flush so to be safe, run the flush with the old impeller and relplace after.

 

[RichardS]

Small outboards have tiny water passages that block very easily, in addition they are usually alloy which can corrode in salt water.

Does the Santana 28 have a small diesel outboard engine? I always thought that small outboards were invariably petrol but I'm no expert.

Richard

 

[RichardS]

I have recently bought a Santana 28 with no indication of hours run on the diesel. I would like to flush the raw water system to give me a starting point. Can I use automotive radiator flush to remove any possible buildup of calcium in the system?

It sounds as if you have a raw water cooled diesel without any fresh water circuit. If you mention the model of engine that would help.

If it is a raw water engine then flushing is not so straightforward because the flush will just go through the bypass and probably not get to where any build-up would be causing the most trouble. Is is possible to flush such engines by removing the thermostat/using a clamp on the bypass hose/using a separate pump but the model of engine is vital.

Richard

 

[simonfraser]

the yard i keep my mobo with inboard diesel does a great trade in replacing corroded engine parts.
mainly for boats that use cooling water without a heat exchanger, as in ones designed for lake use.

i rinse mine, with a heat exchanger, out after every use using muffs and a hose, takes 10 mins, whats the problem ?

 

[Heckler]

As Medman, I have just hauled out for the winter as I need some work doing on her. Have a Volvo 2003T, I disconected the water inlet and connected a hose pipe and ran the engine for a few minutes, then made a 50/50 antifreeze / water mix in a bucket and put the inlet into that and let it suck it through for its anticorrosive properties.

I dont think the previous owner bothered and I had a pinhole appear in the copper raw water pipes a while ago, I am assuming this means that they all now need replacing.
I also removed the pump impeller, changed the oil and filter and cleaned the air filter.
Of course this is for a long lay up, I wouldnt bother for short periods.

Re the y valve - nice idea and convenient, but its so easy to do any way Im not sure as to the need.

Just be aware that some of the VP engines with MS2 gearboxes had the gearbox insulated, it was to prevent electrolysis in the copper raw water pipes that took the raw water cooling water through the gearbix to cool it before it reached the pump. If someone has bypassed the insulation then that could explain pinholes!
Stu

 

[[163233]]

If it is a raw water engine then flushing is not so straightforward because the flush will just go through the bypass and probably not get to where any build-up would be causing the most trouble.

I've got a raw water cooled engine with an unimpressive throughput too...

Would a bucket under the exhaust and looping it back through work so the engine can be run up to temp on the flush solution or are there problems doing that?

Would fresh water flushing achieve anything in a raw water cooled engine or are any deposits too hardened?

 

[VicS]

I've got a raw water cooled engine with an unimpressive throughput too...

Would a bucket under the exhaust and looping it back through work so the engine can be run up to temp on the flush solution or are there problems doing that?

Would fresh water flushing achieve anything in a raw water cooled engine or are any deposits too hardened?

That can be done but you will probably need a descaler such as Rydlyme to do anything worth while.

Before doing that check the exhaust injection point for possible restriction of the water flow

 

[RichardS]

That can be done but you will probably need a descaler such as Rydlyme to do anything worth while.

Before doing that check the exhaust injection point for possible restriction of the water flow

One of our forumites (Mark, I think, but I can't remember his forum name) wrote an excellent article in PBO last year about Rydlyming his raw-water cooled engine. He was very pleased with the results and gave a special mention in his article to the help he had on this forum.

I'll try and remember his forum name so you (not Vic) could PM him and draw his attention to this thread.

It's Mark Ryan aka "MagicalArmchair" .... here he is before he Rydlymed: http://www.ybw.com/forums/showthread.php?442753-Calling-all-Yanmar-Diesel-engine-enthusiasts

Richard

 

[Mistroma]

As Medman, I have just hauled out for the winter as I need some work doing on her. Have a Volvo 2003T, I disconected the water inlet and connected a hose pipe and ran the engine for a few minutes, then made a 50/50 antifreeze / water mix in a bucket and put the inlet into that and let it suck it through for its anticorrosive properties.

I dont think the previous owner bothered and I had a pinhole appear in the copper raw water pipes a while ago, I am assuming this means that they all now need replacing.
I also removed the pump impeller, changed the oil and filter and cleaned the air filter.
Of course this is for a long lay up, I wouldnt bother for short periods.

Re the y valve - nice idea and convenient, but its so easy to do any way Im not sure as to the need.

Just be aware that some of the VP engines with MS2 gearboxes had the gearbox insulated, it was to prevent electrolysis in the copper raw water pipes that took the raw water cooling water through the gearbix to cool it before it reached the pump. If someone has bypassed the insulation then that could explain pinholes!
Stu

Stevie_T created his post in 2005 and hasn't logged on since 2009, probably won't spot your response.

On bright side, swampy396 did get a quick response.