We look forward to providing you with fast, dockside descaling. There are a few points that need to be covered during the arrangement for service.
A typical private vessel service call takes between 3 and 8 hours; depending on the scope of work performed. While we are fully capable of autonomous service; we welcome and encourage our clients to be present. Some engine, generator and system installations prove 'unique'; and a little local knowledge really helps.
Our descaling solution dissolves zinc during the service process - so we can either remove existing zincs and substitute with plugs, or can replace the zincs with new ones you provide after descaling. We recommend new replacements as part of prudent maintenance. It is also a great time to replace impellers and thermostats. Please have all of these items on-board and ready prior to our service call.
If you wish us to service the freshwater side of your engine cooling system, we will be happy to quote for removal of anti-freeze, disposal, and installation of new 50/50 anti-freeze/distilled water mix; or you may wish to do this yourself.
Prior to service, we will jointly execute a service agreement that outlines the scope of work to be performed and defines liabilities. For example, our descaling is extremely effective and may dissolve accumulated rust that has been covering small pinholes in heat exchangers that consequently allow fresh and raw water to mix. Issues such as these are very rare, but beyond our control; and are indicative of equipment that had previously degraded to the point of requiring replacement. During the descaling process, we can usually help identify other areas of concern you may wish to address, such as skeptical hoses, etc.
Probable Causes & Tips
In Order of Probability
1.
Blocked or Clogged Sea Water Strainer
If blockage is caused by scaling or growth - Clean manually or drop in a Bromo tablet in to clean.
2.Through hull scupper blocked.
Close seacock and remove hose. Open seacock slowly to verify. If plugged, try taking a fresh water hose with nozzle to break debris up - Next go overboard and scrape
3.Raw Water Impeller - See (6) when you inspect
Remove cover, pull impeller and inspect. Replace if necessary, but if vanes are missing there is a good chance they are stuck in your heat exchanger. Open inspection plate and try to retrieve.
4.Thermostat
Remove thermostat and test in pot of water on stove using a baking thermometer. Beware: If engine overheated enough, the thermostat can be damaged by the incident and even if found to be bad, may not be the source of the problem.
5.Heat Exchanger, Oil Cooler, Transmission cooler on raw water side of system has scale, insulating the core from cooling the fresh water or block. Crumbled or broken zincs are significant contributors to blockage.
Have engine descaled by a professional which circulates through all components, versus paying a mechanic to come and remove the unit - have it cleaned - reinstall - and hope it was the unit selected. Usually, it is the Heat Exchanger, but often enough it is the transmission or oil cooler that is blocked restricting the necessary water flow to accomplish sufficient heat transfer. This process also dissolves any zinc debris in the system, which is why they're removed before process is begun.
6.Raw Water Pump Plate is worn.
If the cover has not been replaced on an older water pump, it is likely to be worn. Depending on severity, the void created by the wear can affect the efficiency of the pump to supply ample cooling. Try sanding the plate, or thoroughly cleaning the outside and flip it. Always apply a new gasket, as a pin hole will suck air in, again causing a reduction of raw water flow.
7.Fresh Water side of the system has scaling
This is a good possibility if your anti-freeze mix has been diluted with city water versus distilled water. City water has minerals and other qualities which lend themselves to scale buildup.
- NO SET SEQUENCE ON THE FOLLOWING -
A.Too Much Anti-Freeze
YES - Too high a concentration of anti-freeze is a problem. Anything stronger than 50/50 cuts down on the mixture's cooling ability. In fact, to address problems when the sea water is extremely warm, you will find that by cutting the anti-freeze to a 25% mixture concentration, your engine operating temperature will come down 10 degrees or more.
B.Head Gasket
Check oil - If water or anti-freeze is present, undoubtedly you have a head gasket issue
Fresh Water System: Losing anti-freeze but neither see it in oil or elsewhere in bilge. It's highly probable head gasket has a crack, and anti-freeze is exiting out exhaust.
Raw Water Cooled Engine: Has to be significant. In the above case of a fresh water system, the breech by a mere crack itself doesn't result in overheating, the resulting decrement of coolant causes the overheating.
C.Bad Hoses
While a hose may look "OK" on the surface, it is common enough to have the inner lining collapsing at varying degrees, thus you may not visibly see restricted flow, but it's there. Also, carefully check hose clamps that they are tight. A small leak that enables pump to get air will negate the vacuum and result with insufficient water flow.
D.Exhaust Riser Blocked
Much like the collapsing hose, a riser can become partially blocked restricting water flow. Exhaust gases mixed with salt water create a highly corrosive compound. Depending upon severity, the engine may have a different sound as it's not able to adequately exhaust. A descaling process as we use is not applicable to perform on the exhaust riser, as should there be blockage, the flushing solution could get backed up and flow back into the engine through the exhaust manifold. Best thing to do is open it up and clean as best as possible. You may find you need to replace it.
E.Fresh Water Pump
At the end of the list, but not necessarily the last thing that might go wrong. If the pump is going bad, usually you'll notice coolant in the bilge, which is a sign of the seal going bad. If it has broken the shaft internally, or not turning, you should be able to detect that water doesn't flow when the thermostat should have opened by observing the coolant through the fill cap. DO NOT OPEN WHILE HOT ! ! !
AND LASTLY - ITS NOT THE BEST OF NEWS...
The old girl may just be worn out!
Replace or rebuild - Get a mechanic first!
Engine Running Hot?
Let us know if this information was helpful, BUT MOST IMPORTANTLY, PLEASE ADD SOMETHING IF YOU CAN! Send your remarks or experiences and this resource will be updated.
Many thanks, Mike Payne
