I've notice that my coolant has gone from a bright yellow in color to a brown color within the last 3K miles or so. This color change was rather sudden which is what concerns me the most. Up to this point I have been following Fords maintenance schedule closely and was considering doing the recommended 100K coolant change soon. But.....would anyone have an idea as whether this sudden color change could be an indication of head gasket or oil cooler failure or just old tired coolant? I'm the original owner of the truck and it is an '05 F350 4X4 6.0L PS with babied 99,500 miles. As you can see because of the miles why I'm concerned about any potential head gasket or oil cooler failure. Is there a way to isolate head gasket failure vs old coolant, any type of lab test that can be done on the coolant? Other then this the engine runs great and there doesn't appear to be anything unusual with the engine oil (color ok and NO loss between changes). Is the coolant special like the ATF fluid or can the newer "any color any make" Prestone be used for the coolant?

 

possible that you have an oil cooler that is starting to leach oil into the cooling system at a small rate. Also its possible that the ph balance has gone way off and the coolant is starting to turn brown from the improper ph. the ph level can be tested with a "test strip" the oil cooler you would need to moniter eot ect temp and look at the split no more then 15 degrees but if it only leaching it may still pass.

 

thanks cheezit, I was thinking that maybe the rust inhibtors had gone bad and what I was seeing was just rust. I'll have to find some litmus paper and for a quick test. Do you know what I would expect to see from fresh coolant?

I've run Prestone in GM and Mitsu cars for over 5 years and 100K miles without this type of color problem. Do you know whether there is anything special about the Ford coolant or would the Prestone "any color, any make" meet Fords specs?

 

The coolant to use is important.

What consistency is your coolant? Oil in the coolant will look brownish and quickly begin to form a sludge as it is "emulsified" with water.

Also - even though the recommended service interval is aprx 100k miles. There is lot of evidence linking poor coolant health to failed oil coolers, which leads to failed EGR coolers, which can cause head gaskets to leak or engines to hydrolock. Flush your coolant every 50k miles to be safe. In your case - be sure to use the VC9 cleaner.

 

And install a coolant filter if you don't have one.

 

well... I drained and flushed the coolant using a modified approach to the recommended procedure by memebers on this board. I started by draining the old coolant, then disconnecting the coolant hoses that were easy to get at, using the garden hose I back flushed through the different hoses until the water flowing out of the engine was clear. Closing everthing up again I refilled with distilled water (about 5 gal ), ran the engine for a short time, then drained the water, I did this twice. Lastly I refilled with Zerek G05 and distilled water to proper mix and level using a 70% Zerek / 30% water mix. Based on a 27.5 qt capacity this turned out to be about 4 1/2 gal Zerex plus an additional 1/2 gal distilled water. Yes, I know I'm not in Alaska but last year we had a real temp of -34 here in northern Ill and a 50/50 just does not seem to be enough to allow for a little margin.

Over the weekend I put 500 miles on the new coolant. Color of the new coolant looking good so far. I guess it was old tired Ford coolant rather then an engine problem that was the cause of the coolant color change. This appears to be another maintenance item that needs to be modified from Fords recommended 100K miles to 50-60K intervals as the Ford-truck members have recommended.

 

Just an FYI - Ford does not recommend going more than 60% on the antifreeze concentration. I assume it is harder for the water pump to pump it if it gets too high in concentration.

 

Do you have that information printed in any Ford document (wonder whether that is a cavitation issue)? And what do the Ford vehicles in Alaska and Northern Canada use when the temps drop low enough to require a 70/30 mix ?? Personally I would want to stay indoors if it ever got that cold.

 

Yeah I have the Ford document on that somewhere. I can copy and paste the key parts of it tonight when I have a chance to look for it.

 

It's in your owners manual under "checking engine coolant" A mixture of under 40% or over 60% The engine parts could become damaged, or not work properly.

 

Thank you sir!

 

Correct me if I'm wrong but "Power Stroke Owners Guide Supplement" # 5C3J19A285-AB states(page 44-45) in part:

"....
-it may be necessary to increase the coolant concentration above 50%
-never increase coolant concentration above above 60 %.
-increasing engine coolant concentration above 60 % will decrease the overheat protection characteristics of the engine COOLANT and may cause engine damage.
- refer to the chart on the COOLANT to ensure the coolant concetration in your vehicle will provide adequate freeze protection at the tempatature in which you drive in the winter months.
..."

If we examine the temp protection chart for the old coolant (green stuff) one will see that the green stuff protection fell off at a 60% and higher concentration levels. It is difficult to determine from the owners guide whether the recommended max concentration level of 60% is due directly to limitation of the Ford Premium Gold Antifreeze or some other factors. However as noted above, the language is very specific "coolant concentration above 60 % will decrease the overheat protection characteristics of the engine COOLANT " . This language is quit clear in that the characteristics of the coolant (Ford Premium Gold) will decrease overheat protection if the concentration is greater then 60%.

If one examines the specifications for most modern G05 spec antifreeze i.e. Zerex G05, G05 offers increased freeze and overheat protection up to 70% concentration levels per the manufactures chart and G05 antifreeze does not have the lower limitations which Fords Premium Gold Antifreeze appearantly exhibit at higher then 60 % concentration levels.
Most G05 antifreezes print on the container and their data sheets further support that they meet and exceed Fords requirement specification WSS-M97B51-A1. Look up the data sheets for the antifreeze you plan on using.

Based only on the language of Fords owners guide, I'm not conviced that G05 concentration levels of up to 70% is harmfull to the engine or cooling system. Also what I'm figuring is that if a leak is encountered in a remote location and can be fixed, then all that one would need to do is add distilled water and get on the road again yet still have sufficient antifreeze protection. The dollar cost for the additional protection afforded by a 70% concentration of G05 is minimal and may under limited circumstances be a benefit.

 

70% is OK for arctic weather. Higher concentration, the better the antifreeze properties up to a point.

Here is an observation from another forum:




Where I am, the water is hard / awful, so what I do is never use tap water in the rad, but flush and fill with mix of distilled water.

 

I understand your thought process. My question back would be - "Why take any risks w/ an engine so many people are already complaining about?".

Your "antifreeze" is in your engine for three main purposes. One purpose is clearly so that your fluid does not freeze while in your engine in extremely cold weather. A 60% solution protects to at least -50*F.

Another one is corrosion protection.

The third purpose is to ensure that heat can efficiently be removed from your engine. This heat removal is based on several properties of the coolant (thermal conductivity, pressure/temperature boiling point, etc) AND the flow rate of the circulating fluid (water pump flow and pressure curves). There is a point in concentration where your coolant properties will begin to hurt the heat transfer coefficient and the pumping rate. Ford and International know this point - I don't and neither does the coolant manufacturer. We all depend on them to tell us what the upper limit is.

The real question to answer is - what benefit are you looking for when you go to 70% and why is it worth the risk of exceding a Ford spec (one that carries a warning about engine damage).

 

BTW - the G05 coolant is a phosphate free formula.