brown sludge in antifreeze plastic reservoir

[pdnervo]

i have a Westerbeke 30B.... and there is a plastic reservoir that holds the extra antifreeze from the heat exchanger.... there somehow appears this brown sludge on the bottom of the plastic reservoir... the engine seems to run fine... no problems... am i to concerned about that sludge....
i notice that the mfg says to use the same antifreeze all the time.... i got the boat used and am putting in the blue stuff from West Marine...thats all they got.... any info on this ....thanx....pn

[Sailmonkey]

Hard to say what the sludge is, are you adding antifreeze on a regular basis? What was the last time you flushed the system? did you flush the system when you changed types of antifreeze? As near as I can tell the blue stuff is propylene glycol, this shouldn't cause any problems if mixed with ethylene glycol.

[delmarrey]

If your motor has a lot of aluminum internal parts, like most German motors do, you need an antifreeze especially for those motors. Other antifreezes eat up the aluminum and leave deposits behind. Had that problem with an Pathfinder (VW) motor.

Had to replace the water pump, thermostat housing and a block casting. But with the Audi/VW antifreeze the sludge went away.

[SunDevil]

This is a big guess, but I've heard of it occurring in my model of car that oil will get into the coolant side of the engine block through a crack.

But read this:
http://www.w-body.com/showthread.php...lant-should-be

It looks like there are different causes of this from too long of a time between flushing, to mixing the wrong antifreeze types, to oil.

[Therapy]

Used to be you could tell the different types of antifreeze by the color.

Can't do that any more.

Many of the newer aluminum engines need antifreeze that is silicate and borate free.

Find out what Westerbeke says (it is not in the manual for the 30 B three) and let us know please.

They definitely say not to mix different types as a percipitate can form that can be damaging.

This sounds like you have a percipitate.

Get the right stuff and do a complete exchange. Not easy if you have a water heater in the system that is lower than the engine.

[barnakiel]

I have seen similar sludge on a Westerbeke based genset:

- the antifreeze water was never changed,
- the anodes were gone.

I think it a good mix of dirt, bacterial growth and corrosion.

Drain, clean thoroughly (flush), replace anodes, fill with fresh antifreeze. Observe.

b.

[gjordan]

I had a car(Saturn) that got oil in the coolant. Formed a nasty brown sludge, but no sign of water in the oil. Called the dealer and they said OH Yes, the heads crack in a certain spot that lets oil into the water but not water into the oil. Scrapped the car and chocked it up to a learning experience. Do all of the thing suggested here, but you might have a cracked head that is very hard to diagnose. Good Luck_____Grant.

[JimWitt]

If the sludge iis in the bottom of your reservoir as you said it is not oily residue, that is good news. it is likly sediment from corrosion. I agree with flush and use a modern coolant for multi metal engines.