Coolant Question for the gurus

Erdoc48

Erdoc48

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61
Location
Myrtle Beach, SC/ Sometimes Colorado
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94/00/04 STs, FSC600
I did the timing belts on both ST’s near the end of 2016 for the 94/early 2017 for the 2000 and when I did (since the radiator came out and coolant had to be drained), I used Prestone 5 yr/150K mileage 50:50 pre-mixed coolant (no silicates, probably OAT coolant). Both the 94 and 2000 have ~ 20K miles on them since then (yup, I need to ride more). I did my yearly maintenance yesterday with oil and filter change as well as brake and clutch fluid swaps. The rear drive oil only has 7K miles on it per bike so I left that alone and will change it next year with the oil change (I do the oil changes at 4K miles).

OK, so here’s the question- change coolant or leave it alone, for now based on:
-pH of the fluid is 8.5, so not acidic (both STs)
-fluid tested with one of the bulb devices sold by Prestone (needle goes right up to max freeze/ boil protection- 265 degrees F) and fluid is green (actually green-yellow) but otherwise nice and clear (so not cloudy or discolored)
-as a control, I tested the fluid right from the Prestone jug which was pH 8.5 and same color, clear as what I’m obtaining from the bikes, and needle also goes to 265 degrees of protection).
One of these: https://prestone.com/product/prestone-antifreeze-coolant-tester/

Leave it for another couple of years until maybe 30K miles or swap it out? Not hard to do I guess, just a little more work intensive to remove the left mid fairing so I don’t make a huge mess. I will assume, maybe wrongly, that when these bikes were produced, the fluids used were likely not as ‘hearty’ or long lasting as what is available now. No such thing as too much maintenance I guess, but hate to waste what appears to be good coolant.

Thank you for any opinions.
 
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Leave it. Prestone lasts way more than that.

Change it next time you have all that apart just so you will feel better.
 
I believe the 5yr/150K miles is a whichever comes first. Anti freeze has a package of corrosion inhibitors and these will deteriorate with time. I have no idea how the ph changes with age, but I can tell you from personal experience (and a tongue lashing from my mechanic friend - I should have known better) that leaving the coolant in for way longer than you are supposed to can lead to some real engine damage. I doubt a year or more over the stated 5 years will make a difference, but to be honest, that is not based on any substantiated information.

Why not call Prestone cutstomer service and ask them? Tell them the results of your Prestone tester. You should be able to suss out if the person you are talking to at the company knows nothing more than what he/she is reading off a computer screen or is indeed knowledgeable.
 
FWIW, on my BMW F800GT I asked a independent mechanic to change the coolant when he adjusted the valves. He talked me out of it.

BMW came out with a bulletin saying the coolant is now for the life of the motorcycle. When someone talks me out of work that would make them easy $$$, I tend to trust them.

Chris
 
SMSW said:
I believe the 5yr/150K miles is a whichever comes first. Anti freeze has a package of corrosion inhibitors and these will deteriorate with time.
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As above.

I would do every 5 years. Coolant is dirt cheap and coolant system parts are not.
 
Where the acidity of the coolant becomes issue is with aluminum components are subject to electrolysis quicker than iron or steel and show damage faster.
In your radiator is a bunch of tubes that with acid become a battery, granted it is low voltage. The PH reading measure the acidity that causes this. I use a voltmeter to check mine for voltage.
Both methods give dependable results.
One extreme case I had with acidic coolant was the blades on a water pump were completely rotted off and engine was overheating.
Where I differ with BMW is the dissolved solids that are suspended in the coolant. I am sure we have heard about having coolant recycled at the neighborhood shop and additives being reintroduced. What that does not address is the dissolved solids which show up as worn or damaged seals and sediment at the low spots of the passages like the radiator.
Reading the engine failures closely give a view of how important coolant is, ie blown head gaskets from overheating, blown head gaskets leaking coolant, leaking water pump.
Remanufactured works well, I don't want to confuse recycled with remanufactured, the reman is distilled to the core and only the base coolant is reused, the additives are incinerated.
I flush my coolant on a regular basis, now with more aluminum components the coolant is just as important as the oil, which it always has been, but slipped under the radar because it easy to overlook
 
If the coolant your using now has any remenace of the old 3 yr stuff the 5 yr/150,000 has been compromized. It's cheap and doesn't take much, just do it.
 
Every 3-4 yrs I dump whatever coolant will drain easily from the vehicles. Then I refill and return to service. I figure that the partial change gets the majority of the coolant replaced. Never bother with flushing or anything else and have never had a coolant related issue with anything. Seems to work.
 
ST1100Y said:
'cause they expect you to buy a new one every year anyway...
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I was going to be even meaner and say "that's all the longer they last anyway".

But regarding the topic of coolant changing intervals, I had my own bad experience with that years ago on my ST1100. I somehow just forgot about coolant changes for probably about 10 years, and when I drained it the coolant was in very bad shape. I've been on these forums since 1997, so I know I would have changed it with the correct coolant, and at one time I had a bottle of the Honda coolant, so I think that's what was in it at the time.

Shortly after that my water pump bearing started making noise, so I changed the water pump, and the impeller blades had all corroded to the point where they were all just stubs without the 90° bend in the ends that presumably moves the water.

The OP only has 20k miles on his, in my case the mileage was probably 50-60k, which is higher, but not a lot higher. Makes me wonder why his is doing so much better than mine after 7-8 years, does it stay OK up to a point and then deteriorate quickly? The other possibility is maybe it was as much as 12 years on mine, I didn't write it down when I changed it the previous time, so I can only guess.

Anyway, its really easy to drain most of it from the radiator drain plug and put new coolant in periodically, so that's what I do now. I know that doesn't flush the entire system, but if I'm periodically putting in new coolant I'm never going to run into the issue I did before.
 
A Chevy I’m working on. Old coolant, corrosion, cracked head etc. Corrosion inhibits coolant flow to critical areas.

Coolant is cheap.
 

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Or you could use Evans Waterless Coolant and pretty much forget about it. I've had it in my 1300 for most of its 191,000 miles without any problems. I changed it once when I had to take the radiator off to clean it, and even that probably wasn't necessary.
 
Daboo said:
FWIW, on my BMW F800GT I asked a independent mechanic to change the coolant when he adjusted the valves. He talked me out of it.

BMW came out with a bulletin saying the coolant is now for the life of the motorcycle. When someone talks me out of work that would make them easy $$$, I tend to trust them.

Chris
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BMW came out with lifetime lubricant in the non vented final drive of the R1200xx series. Lifetime it was and the lifetime turned out to be as little as 20,000 miles. Within 2 years BMW back pedaled and revised the interval to 12,000 miles and added a vent.
 
Even though my owners manual specifies replace every 2 yrs, I stretch it out closer to 3 yrs.
 
...so...how often do you ("you" in general, not specifically) change your car's radiator fluid? Every 2 yrs? Every 3 yrs? Every 4 yrs?

I'll bet a lot of us don't even give our car's coolant system a second thought.

Chris
 
Daboo said:
...so...how often do you ("you" in general, not specifically) change your car's radiator fluid? Every 2 yrs? Every 3 yrs? Every 4 yrs?

I'll bet a lot of us don't even give our car's coolant system a second thought.

Chris
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Better yet, how often do you (or does your mechanic) flush your brake system? Two mechanics told me customers don't want to pay for the extra time and fluid.
 
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