Flushing Coolant System of Older Volvo Diesel?

[gwy]

Looking for suggestions about flushing my older Volvo Diesel, model MD 11D.

The boat is on the hard and I had the circulation pump rebuilt. I've attached a couple of pictures for reference. Yes there are two alternators, one is the new replacement for the other.

Here's the issue - the circulation pump (the lighter green) was leaking, hence the rebuild; however, before we were able to take it off we used "stop leak" pellets to try and get by. The engine is "fresh water cooled", it has the raw water cooling and the heat ex-changer for the closed cooling system. That heater ex-changer is the green circular tube above the circulation pump.

The boat is on the hard as it's been being slowly fixed up and the engine's not been run in a couple years, though it was winterized before lay up and now it is time to get this part done.

The individual who was able to rebuild the circulation pump said to be sure and flush the engine and get all the stop leak pellets out so they won't jam the circulation pump and make it leak. [B]That is what I do not know how to do. I need to flush the engine without starting it to be sure that I get the "stop leak" stuff out of the system before reinstalling the circulation pump.

If I am correct in my understanding there is no mixing of the raw water and fresh water coolant, so it's the freshwater cooling system I have to flush out.

My thoughts were to get a drill driven small pump or hose and try to push fresh water though the lines starting from the place where I add the coolant. Any and all suggestions welcome.


Thank You,

Greg.

[wingless]

The engine can be operated using a garden hose instead of the raw water intake.

The engine can be operated w/ the fresh water side continuously dumping, while replacement water is added at the top.

If running while dumping the fresh water side, then the thermostat won't open / won't flush that circuit. Thermostat removal / replacement is required to flush that circuit with this method.

Many times the interior requires physical scraping to remove crud. Freeze plug removal exposes parts of the interior that could be scraped for cleaning.

[gwy]

Thank You, I didn't know that about the thermostat. I need to flush the engine as best I can without operating it - that's my biggest question. I don't want to operate it until it is flushed because anything that goes through the system goes through the circulation pump and those are the lines I have to clear first because they likely still have some of the "stop leak" pellets that could clog the circulation pump. Suggestions?


Greg

[DougR]

Flushing the FW side of the engine without running isn't the easiest thing due to the hard piping and convoluted construction of the system, but here is what I would do:
- remove the hose from the bottom of the expansion tank and use that as the entry point into the system. Pump your new freshwater into that pipe. Unscrew the cylinder drain cocks on the bottom of each cylinder and completely remove the plugs from the fitting to allow maximum flow. Just let the flushed water from the cylinders run into the bilge. You can clean it up later.... During this step you will have some flow out of the small breather line connected to the circ pump. That's ok, just let it flow to the bilge.
- now pump water into the line. This water will flow down to the circ pump, thru the circ pump and up to the bottom of the exhaust manifold. Into the manifold, from the manifold into the two heads, from the heads down into the cylinder blocks and out of the blocks thru the opened drain cocks. Flush for a while.....
- now stop the flush and replace the drain cocks in the bottom of the cylinders.
- remove the two hoses which come out of the front outboard side of the exhaust manifold ( for the house hot water heater?) and run new hoses from those hose bibs into the bilge. Pump your water. One or both of these might flow. This will force water from the cylinders liners up into the other side of the heads and out into the second half of the exhaust manifold. Let it flow a while.
- now you have flushed the entire engine, and you might have gotten some back flow thru the heat exchanger via the small bleeder line at the top front of the exchanger. Probably this will be enough to clean the HE, but if not you might have to remove the pipes at both ends of the HE and flush it.
- Flush out the house hot water heater by pumping thru the two hoses which you removed from the front outside of the exhaust manifold.

Reassemble everything and fill with 50/50 antifreeze mix for the balance of the storage. When you finally start the engine, remember to top up the expansion tank as there will undoubtedly be some air pockets remaining from the fill that will need to work their way out.

DougR

[gwy]

Thank you that is exactly what I was looking for.

Very much appreciated.


Greg