Can you flush Coolant side of Heat exchanger with automotive radiator flush. Also is it necessary to use distilled water for the flushing and rinsing process or can you use tap. I of course will use Distilled Water to mix with coolant in the final fill. Not trying to be cheap but this is a twin engine 50 ft cruiser with twin Volvo Diesels. Holds 16 gallons in coolant side. I already Lugged 32 gallons down there and was not wanting to have to carry more. Plan is: Drain. Refill with tap water. Run 10 min. Drain. Fill with Distilled water and Royal Purple Flush. Run 1 hour. Drain and fill with Distilled water and Royal Purple ICE. Only doing 1 engine at present. Boat is in Miami and will never travel North of Jupiter so I don't need freeze protection.

Chris

Looks good to me. Why flush the coolant side? The seawater side is what gets nasty.

Coolant in Autos or marine needs to be flushed every so often. Like every 5 yrs or so. Most people don't do it but we boat in some very warm water in the summers. Water temps in south florida are regularly in the mid 90's in the the summer here. I have the seawater side pickled about every 3 years but have never changed the coolant side. I bought the boat used. Its a 2005. Dont know if the coolant has ever been changed.

Chris

Gotcha. It can't hurt flushing it with unknown history. Good move.

use Trac's descaler . and follow there instructions .. you should be able to find it at any marine supply store .

Get coolant test strips that way you're not flushing and filling for nothing.

nice thread

It is maintenance per OEM to check and clean any crap that is in the heat exchanger every year anyways. Also this would require new end cap gaskets and orings. If never done - I would not go over 4 or 5 years for the end cap gaskets as they become swollen and blown out from their original shapes. This alone causes cooling issues. Very common issue.

Can you pull the heat exchangers and take them to be cleaned? I took all my heat exchangers, intercoolers to Broward radiator and had them tank cleaned. They were like new. If you are draining the coolant anyway shouldn’t be that tough.