Rust color in Antifreeze

[buddybear]

I use antifreeze 50/50 for my M25XPB 2001, I have no issues with over heating. Last year I started to see some rust colored water under the engine and eventually had a loss of coolant when I checked the manifold. I found that the fitting from the manifold which went to the overflow tank was clogged and the hole to the manifold was also clogged. I fixed these issues. I have drained the coolant from the drain on the Heat exchanger 3 times and it still comes out this rusty brown color. The coolant does not appear to be leaking. The coolant I use is a 50/50 mix color is green. I am guessing I have rust in the engine. The bottom line is I have no overheating problems. What would be any suggestions. It appears rusty looking antifreeze will still do the job cooling the engine. Any suggestions would be appreciated. Attached is a picture of the coolant color.

Thanks,
Mark

 

[Ralph Johnstone]

I hate to say this but any chance you've got a leak from the raw water cooling into the AF system ? That looks like pretty serious corrosion. Someone mentioned a test strip for NaCl in water a few days ago.

Identifying water in the bilge.

The last couple of times that I've taken my Catalina 22 with a wing keel out for a sail, there has been a small amount of water in the bilge. I've tried to find the source and have not been able to find it. I'm not sure if it is salt water from where I have it slipped or fresh water from rain...

forums.sailboatowners.com

See post #2.

Once you're sure you have a sealed system, you would want to use a cleaning flush on the engine. Check the post archives for recommendations.

 

[Don S/V ILLusion]

Pressure test the system to ensure it isn’t leaking after which you can flush with a rust removal acid bath but be cautious of the warnings associated with doing so.

 

[capta]

I rarely use chemicals to clean my fresh water side of the cooling system. It can cause scale to fall off the inside of the block and clog the smaller passages. It can also make a freeze plug begin to leak, which it might not have done for some years. Also, many fresh water circulation pumps have alloy housings, which might react poorly with some acid block cleaners.
I flush from the heat exchanger to the lowest outlet valve in the fresh water system, and need to clear that end quite frequently as it is a small valve. I used an engine rust inhibitor rather than anti-freeze in the tropics, and it works very well to control the rust.

 

[buddybear]

I hate to say this but any chance you've got a leak from the raw water cooling into the AF system ? That looks like pretty serious corrosion. Someone mentioned a test strip for NaCl in water a few days ago.

Identifying water in the bilge.

The last couple of times that I've taken my Catalina 22 with a wing keel out for a sail, there has been a small amount of water in the bilge. I've tried to find the source and have not been able to find it. I'm not sure if it is salt water from where I have it slipped or fresh water from rain...

forums.sailboatowners.com

See post #2.

Once you're sure you have a sealed system, you would want to use a cleaning flush on the engine. Check the post archives for recommendations.

Thanks for the replies. I did another test and do not understand the system completely so I don't know what these results mean. Without starting the engine I poured water into the manifold and had the drain plug out of the bottom of the heat exchanger and the water coming out of the heat exchanger was clear just as it looked when I poured it into the manifold. What would this clarify in my trouble shooting?

Thanks,
Mark

 

[Ralph Johnstone]

What would this clarify in my trouble shooting?

Not much. The rust needs to be agitated by the moving water when the engine is running. As long as you get rusty water coming out AFTER running the engine for a while, you still have iron oxide sediment in the block. Follow @Don S/V ILLusion 's prescription at this time and pressure test. I agree with pressure pressure testing unless you have some of the original rusty water remaining to test for the presence of salt The pressure test equipment is worth a few bucks but the possible damage in there is BIG bucks.

Let us know.

 

[buddybear]

Not much. The rust needs to be agitated by the moving water when the engine is running. As long as you get rusty water coming out AFTER running the engine for a while, you still have iron oxide sediment in the block. Follow @Don S/V ILLusion 's prescription at this time and pressure test. I agree with pressure pressure testing unless you have some of the original rusty water remaining to test for the presence of salt The pressure test equipment is worth a few bucks but the possible damage in there is BIG bucks.

Let us know.

The heat exchanger which I replaced in 8-2015 from Mr Kool never had a drain valve after several trips to the hardware store I now have a drain valve which has a hose attachment so I can easily drain the heat exchanger. I am putting in distilled water and once it comes up to temperature I am draining it. It is not as bad as it has been, still some rust, I will post the next drain with a picture.

 

[buddybear]

The heat exchanger which I replaced in 8-2015 from Mr Kool never had a drain valve after several trips to the hardware store I now have a drain valve which has a hose attachment so I can easily drain the heat exchanger. I am putting in distilled water and once it comes up to temperature I am draining it. It is not as bad as it has been, still some rust, I will post the next drain with a picture.

Here are the last two pictures of draining with distilled water to 170 F

 

[JoeWhite]

That looks much better. You must have cleaned it.

 

[Ralph Johnstone]

That looks much better. You must have cleaned it.

But not yet stopped the corrosion.

 

[Hello Below]

But not yet stopped the corrosion.

Ralph, do not today’s premium coolants have additives that would help alleviate corrosion? From Shell Rotella Heavy Duty ELC Coolant

1. Corrosion protection – Corrosion inhibitor technology protects metals against all forms of corrosion

 

[Tom J]

Hoe old is your antifreeze? Flushing the entire system and putting in all new coolant might help. This includes flushing coolant out of the water heater. I used Prestone 50/50 prediluted coolant in my M25xpb for 17 years with no sign of rust.

 

[Ralph Johnstone]

Ralph, do not today’s premium coolants have additives that would help alleviate corrosion?

Yes, but only under moderation such as NO salt water introduced to the AF mix and no excessive amounts of O2 being introduced due to lost AF. Nothing would help under those conditions.

 

[buddybear]

Hoe old is your antifreeze? Flushing the entire system and putting in all new coolant might help. This includes flushing coolant out of the water heater. I used Prestone 50/50 prediluted coolant in my M25xpb for 17 years with no sign of rust.

I am draining it from the bottom of the heat exchanger. Does that not drain it also from the water heater? If not how do you drain it from the water heater.

Thanks,
Mark

 

[JoeWhite]

You can drain the water heater by disconnecting the coolant hoses at engine side and forcing air into one hose using an airpump and catching the fluid coming out of the other hose. This would be a good opportunity to flush the heating coil with distilled water.
Draining the heat exchanger does not remove all fluid from the engine block. There is a bolt on the engine block that should be removed to drain the fluid. Flushing with distilled water is a dood idea.
Visit here for how I performed this task on M35B

Sail La Vie | 1999 Catalina 36 MK II

mei1970.org

 

[Tom J]

I am draining it from the bottom of the heat exchanger. Does that not drain it also from the water heater? If not how do you drain it from the water heater.

Thanks,
Mark

JoeWhite described the process very well. Just draining the heat exchanger would remove very little of the total amount of coolant. Remember, too, that the coolant must be replaced periodically.

 

[buddybear]

JoeWhite described the process very well. Just draining the heat exchanger would remove very little of the total amount of coolant. Remember, too, that the coolant must be replaced periodically.

I replaced the coolant and ran the engine. I am familiar with using the burp method to get rid of the air in the system. I have tried this three times and the engine still goes from 160 to 200. I did add a valve to drain the heat exchanger. Before the engine ran between 160 to 170. I did clean the intake filter for the raw water pump. After the engine was hot 200 I did open the bleed valve for the thermostat I was surprised that no fluid came out. I have not ever tried this before. I have never had an issue burping the engine, I have lost fluid before. What would you suggest that I troubleshoot. Should I take out the thermostat and see what happens, I can plug up the bottom of the heat exchanger and bypass the valve I put in.

Thanks for any suggestions,
Mark

 

[JoeWhite]

The thermostat my be stuck in closed position. Remove and see what happens to the engine temp.

 

[buddybear]

The thermostat my be stuck in closed position. Remove and see what happens to the engine temp.

I was thinking the same thing I replaced it several years ago and have the old one. That was one of the first things you would do with an old car take it out and see what happens .

Thanks,
Mark

 

[Ralph Johnstone]

That was one of the first things you would do with an old car take it out and see what happens .

With that much in the way of rust flying around, the stat could well be plugged.

But, we still don't know what caused the problem in the first place, however what we do know ....................... it's still there.