What's this stuff in my coolant?

[berniedd]

I use the green coolant in my 1998 Honda, and it's now 2 years old (but only 8000 miles in mileage). I've always used distilled water and nothing else to refill the reservoir. A month ago I noticed there was dirt mixed with the coolant in the reservoir, so I filtered it through a paper napkin and returned some of the now clear coolant into the engine. The dirt left on the napkin looked like rust particles, not really much to comment about.

I purposely kept back and stored in an air tight mineral water container some of the filtered coolant. Kept it in the house away from heat and light. It was crystal clear a month ago, but now I see a few bits of stuff floating in the coolant. They look like bits of moss. Can anybody tell me what they are?

 

[Ursae_Majoris]

Coolant goes bad after time as well as mileage. If you use American green coolant, you need to change it; it is normally rated for 2 years. Additives do get used up over time, even if engine is not running.

What you see in the bottle are probably additives. I would flush the engine with Prestone radiator flush and refill with fresh coolant.

 

[660mag]

Did you own the car from the time it was new?

After you do the flush you could upgrade the coolant. Coolant goes acidic after it's service life.

 

[berniedd]

I'm the second owner. But I've had this car for 4 years now.

 

[berniedd]

Today, I measured the voltage between the coolant in the radiator and ground with my digital multimeter. (Car battery was not disconnected for this test.) I read 0.126 volt, so I guess the coolant is still good. IIRC the threshold is 0.5 volt for the coolant to read bad.

 

[Craig in Canada]

An eletrolysis test is an excellent idea, but it isn't testing the coolant itself, per se. This is the technique which you use to find wiring or grounding faults in your electrical system and should be done with the engine running and all electrical loads on. There's a correlation between the reading and the coolant's electrolysis prevention additive, but without knowing the condition of wiring/ground it isn't a good test all by itself IMO.

If you want to know the condition of the coolant itself (particularly without knowing whether you have any electrical issues which would contribute to your voltage reading) you should check pH with test strips or simply age.

You have solids precipitating out of your two year old generic green coolant - just change it. If the car has a dubious and unknown service history consider a flush.

 

[TheShadow]

When you say "Green" coolant, are you talking about "Prestone" anti-freeze? (Etheline Glycol based) Many cars from Japan, come with a BLUE coolant. (Suzuki, for instance)
I have NO idea what that is. ???

What about additives to make 'water wetter' and increase heat transfer. ??

 

[berniedd]

The original coolant had been drained a long time ago and when I bought the car it had green coolant. I flushed the cooling system shortly thereafter, and since then have been using Prestone green coolant as a replacement.

 

[Ursae_Majoris]

Prestone green, as in all makes/all models?
It is a Dexclone, and does not do well when exposed to air in non-pressurized cooling system (the one with caps both on the radiator and overflow bottle).
I would dump it, flush the car and go with G5, Peak Global Lifetime or Valvoline Asian Car antifreeze.

 

[ltslimjim]

The Honda tech we use locally uses Prestone green on all older models like mine, but the newer cars get lifetime/OE equivalent FWIW.

 

[berniedd]

Long time no see. I ran into my cousin 2 days ago and asked him about my coolant. He's a chemist and he says the floaters are probably degradation products of the ethylene glycol. You get more of them at higher temperatures.

 

[Coolant_Man]

Originally Posted By: berniedd
I've always used distilled water and nothing else to refill the reservoir.

Did you have to use a lot of distilled water over time? Using it alone would weaken the coolant to where it wouldn't protect as well. You should use pre-mixed for topping off. You might test yours with an antifreeze tester. You can get the kind that has a glass tube with 5 balls in it at Walmart for $1.

 

[ltslimjim]

You should only ever add pre-mixed anti-freeze/coolant to the reservoir, IIRC, unless you suspect a weak/strong concentration and want to dilute or strengthen without drain. Too much coolant? Just drain the radiator and fill to proper level with 50/50 mix, IMO. Safer than adding straight water, just my preference.

 

[berniedd]

Originally Posted By: Coolant_Man
Originally Posted By: berniedd
I've always used distilled water and nothing else to refill the reservoir.

Did you have to use a lot of distilled water over time? Using it alone would weaken the coolant to where it wouldn't protect as well. You should use pre-mixed for topping off. You might test yours with an antifreeze tester. You can get the kind that has a glass tube with 5 balls in it at Walmart for $1.


I drained the coolant and flushed the system this May. I replaced it with 50-50 mix of Prestone green coolant and distilled water.

 

[Coolant_Man]

Originally Posted By: berniedd
I drained the coolant and flushed the system this May. I replaced it with 50-50 mix of Prestone green coolant and distilled water.

Do you have an idea of how much distilled water you have used since then topping it off?

 

[berniedd]

Originally Posted By: Coolant_Man
Originally Posted By: berniedd
I drained the coolant and flushed the system this May. I replaced it with 50-50 mix of Prestone green coolant and distilled water.

Do you have an idea of how much distilled water you have used since then topping it off?


I don't use the car much, I think I've topped it off only once with 200 cc distilled water-coolant in equal proportions since I changed the coolant 7 months ago.

 

[Coolant_Man]

The way it sounded earlier was that you had been topping off a lot with distilled water only which would weaken the coolant mixture possibly enough to cause rust.

 

[cronk]

Could be the system was neglected over the years and the fresh coolant is cleaning out sediment and rust in the system.
Whatever the case may be, it you have particles in the coolant, it is time for a flush.

 

[Spazdog]

Some leftover stuff that just broke itself free.

It is nearly 15 years old.

I've flushed my Mazda's cooling system twice now since I've owned it and filled it with 50/50 Peak and distilled water.

It still ends up being the original OE Mazda coolant orange in color.

Flushed it with the heater on 'til it ran clear. Took off the expansion tank and cleaned it thoroughly and yet, about a month later, the coolant was orange again.

Doesn't bother me. It's just odd how strong that dye was.