Brown rusty water from radiator

[silverback]

Anybody have an idea what would cause brown rusty water form radiator/coolant reservoir?

 

[Boatsb]

It may be a long shot but I'd guess it may possibly be from rust.

 

[oceanjake]

Lack of rust inhibitors. Probably started out as antifreeze and has been topped off with plain water for too long.

 

[SEVEN]

When you mix metal and water you get rust. You probably ran out of anti-freeze a long time ago and maybe your prior owners filled it with water.

 

[jim rosenthal]

Sounds like it might need a drain, flush and refill.

 

[Glory]

Adding a coolant filter might be a good idea.

 

[dsharp]

What engine? Some 6-71's had steel tubes that carried water to the circulating pump that can rust. I would flush the system and use a corrosion inhibitor.

 

[Cricket]

Been looking for a radiator all day on the boat. none on the CATs, none on the Phasor genset. Did find one on the car. Hmmmmmmm...........

 

[racclarkson@gmail.com]

When you mix metal and water you get rust. You probably ran out of anti-freeze a long time ago and maybe your prior owners filled it with water.

You run, typically, 50/50 coolant/water mix. Old coolant breaks down; rust inhibitors thin out.

 

[Top Hatt Craig]

Here's some verbiage on heat transferability of mineral deposits from the manual.

 

[silverback]

Re: Brown rusty water from coolant tank

Thanks everybody for the advice. And yes, I did say radiator...hey I was tired. And no I have not found a radiator on the engine either. Anyways, I have just replaced the coolant 3 months ago and then again last month. Still coming out dirty. So...I am adding a treatment solution in this weekend and flushing the system. This all started because I had the engine serviced (fresh water and raw water system) by a diesel mechanic in June of this year. After the service the engine ran hotter than before and has gotten worse. Can't run for more than two minutes before temp goes over 220! Found he did not change out the thermostats (there are two on a 853N) so I am replacing them and putting a new fresh water pump on. I will say that at the dock, not under load, the raw water side looks good. The more RPMs the greater the flow. So I do think it is a fresh water issue. Will see how she does after that. If still running hot I am at the end of my knowledge level.

 

[bobk]

Did your mechanic clean the heat exchangers?

Bobk

 

[saltshaker]

You definitely need to flush the engines and replace the coolant with fresh. Your problem may not be rust. If you have a mix of incompatible coolants, they often turn brown and can form sludge. Make sure you aren’t leaking combustion gases into the fresh water side as this too will turn the coolant Brown. 220 is way too hot for a Detroit and can do serious damage. Did you overhear and if so for how long before it could cool down? Was it underload at the time?

 

[silverback]

To the question of over heating. Yes, I was under load. Did not allow temp to stay there for any time. Once she climbed she climbed quickly and I slowed down immediately. Temp drops rather quickly (say 3 minutes).

Heat exchangers were cleaned, per mechanic.

Pulling all coolant out adding new with new fresh water pump today. We will see.

 

[Top Hatt Craig]

To the question of over heating. Yes, I was under load. Did not allow temp to stay there for any time. Once she climbed she climbed quickly and I slowed down immediately. Temp drops rather quickly (say 3 minutes)."Heat exchangers were cleaned, per mechanic."Unfortunately, as a former auto mechanic I have seen many shortcuts taken by unscrupulous coworkers over the years. Some would not do anything that couldn't be proven done, a brake fluid flush would be done by drawing the fluid from the reservoir with a turkey baster then simply topping off, and manual transmission and rear end fluid changes skipped altogether. If you know or trust the mechanic I apologize for being out of line, but if you can check your heat exchangers while they're drained you might find what you're looking for. Can you see new gaskets or sealant or other signs they've been out? Best wishes, Craig

 

[rob71]

Many marine engines are tricky to fill on the coolant side. Because of the elevations of the various components.
An air pocket can fool you into thinking it is full. Does your engine have a bleeder valve ?
Or maybe you can fill it through the opening for the thermostat.
Good luck. Capt. Rob

 

[saltshaker]

Many marine engines are tricky to fill on the coolant side. Because of the elevations of the various components.
An air pocket can fool you into thinking it is full. Does your engine have a bleeder valve ?
Or maybe you can fill it through the opening for the thermostat.
Good luck. Capt. Rob

For this reason when refilling you should always run the engines at idle and no load. Shut down and top off as needed. Once you think it’s at a good level run the engine to get it to temp. Then check again once it cools.

 

[silverback]

Replaced he second thermostat. Mechanic came back to boat and removed two new zincs (both on the intake side of the raw water system. Why? These zinc were 3 inches long and when placed in the housing where the raw water impeller is located and the upstream side of the heat exchanger, they took up at least 40% of the volume area of the housing where raw water had to pass through. Don't know if it was the 2nd new thermostat or the zincs being removed but she now runs at 190 degrees, same as the starboard. Guess I will cut the zincs in half and re insert to see if there is any difference then.

So the next question: I thought I had read an old post about the type of coolant to use in old Detroits. Mine are OLD!! 160's era. Anybody remember

Is there any real reason to be particular about which coolant. NAPA has pre-mix 50/50 for Detroits (pink) but there is green color as well.
.

 

[Boatsb]

Distilled water and nalcool or napacool is best if temps are not below freezing.

 

[Walter P]

I use Detroit Diesel Power Kool. For NJ I mix a 50/50 mix with distilled water.

Walt