Black sludge from HELL!!

[Flyingmike]

I have torn down my A4 to clean every thing out for my fresh water conversion and I am blown away that my motor ran at any sense of a normal temp before I started. I started with an Acid flush this after noon and then proceeded to take it all apart and when I got my side plate off I was blown away at the gunk in there!

[joe_db]

Do look into a filter for your heat exchanger. I ignored the good advice in the Indigo FWC instructions to make a filter and got to clean everything TWICE
It is amazing how much crap gets into a RWC engine.
Someone on here found these things, they look good: https://www.mcmaster.com/#43935k25/=15zqs01

[Flyingmike]

Thanks for the tip, I ordered two of those a few weeks ago, I'm going to put one on my raw water side just to make sure that nothing will get sucked up and block my heat exchanger also.

And I have decided I'm going to put distilled water in my system instead of coolant the first time I run it so that way I can just dump it in my bilge and flush it out a few times that way instead of having to worry about capturing antifreeze and disposing of it.

[alcodiesel]

Mike, what year is your engine? Which FWC cooling system did you do with? How much of a PITA was the job- cleaning, preparing and installing?
Tom at Indigo suggested taking the head off mine to clean it before I go to FWC. That put a huge damper on my enthusiasm to convert (being the king of lazy). I just know bolts and the like are gonna break.

[JOHN COOKSON]

Depending on what you find after you clean up the cooling jacket, it would be a good idea to do a pressure test before proceeding. With that much KRAP in the cooling jacket the KRAP may be sealing a leak into a cylinder(s) which will be exposed when the KRAP is cleaned up.
Also check for leaks at the side plate; the mating surface looks gnarly in the picture.

TRUE GRIT

[Flyingmike]

Mike, what year is your engine? Which FWC cooling system did you do with? How much of a PITA was the job- cleaning, preparing and installing?
Tom at Indigo suggested taking the head off mine to clean it before I go to FWC. That put a huge damper on my enthusiasm to convert (being the king of lazy). I just know bolts and the like are gonna break.

It was a huge PIA, but I was prepared for that, I had 4 days here with absolutely no plans so I made sure to bring every tool in my garage I could possibly think I would need. I pulled the head and manifold and replaced ALL the studs, that was probably over kill but my head was leaking before so I wanted to make sure I could tourqe down the full amount on every stud. I took a small spray nozzle and blasted water in every hole and jacket and lots of work with the shop vac getting that crud out, It took me several hours yesterday of just spraying and sucking. It's a early model engine, for some unknown reason the previous owner had the late model swapped out for this early model.
I am going to use a Johnson pump so luckily I'll be able to cycle the water without running the engine and will be able to see if I have any leaks before I start it up. I got the head and sideplate on yesterday and today is the manifold and plumb the heat exchanger. I got the heat exchanger off EBay for $125 and so for I am about $400 into this project. I'll post pics later today when I get it all together.

[joe_db]

Warning - the electric pump is *terrible* at clearing out air. Make sure - double sure - triple sure - and then some more this is done before running the engine for long. Watch the head temp with an IR thermometer or your hand and if it seems to be getting pretty hot pretty fast, SHUT DOWN and clear some air some more.

[ndutton]

Warning - the electric pump is *terrible* at clearing out air.

However you can help matters considerably by careful routing of all hoses as directly as possible with a continuous uphill gradient to the cooling system fill point. If 'up-traps' are necessary, placing a bleed valve at the up-trap makes purging the system much easier.

I connected my double pump system with a Hopkins 2 conductor rubberized trailer style plug so I can easily disconnect it and connect a 12V extension cord from an accessory plug to run the system for purging with the engine off.

[Flyingmike]

Warning - the electric pump is *terrible* at clearing out air. Make sure - double sure - triple sure - and then some more this is done before running the engine for long. Watch the head temp with an IR thermometer or your hand and if it seems to be getting pretty hot pretty fast, SHUT DOWN and clear some air some more.

I have carefully planed out my plumbing so everything is up hill to the expansion tank and the heat exchanger is the low part of the system. That should help with the air pockets. We will see tomorrow. I also go an extra trailer plug to run the Johnson off my 12V plug, I will run it for as long as it takes to make sure it is free of air pockets before starting it up.

[sastanley]

FM...I also ran plain water and/or "cleaning strength" vinegar thru my 'new' FWC system for an entire season before shifting to antifreeze/water mix.

I also regularly drained and refilled the water/vinegar mix to help cleaning (like multiple oil changes to remove water from the crankcase)