Topping off coolant tanks

Maybe we should talk briefly about how full they should be.
There is some room for expansion needed and should not be totally "full".

If only a couple of ounces is required, where you live either should be fine.

 

Actually, you should not have to top off. If you are losing coolant, more than likely you have a leak somewhere. But in answer to your question, you should always use the Toyota Super Long Life Coolant. Adding water to the system dilutes the coolant and lessens the protection levels that are necessary for the proper operation of your Prius.

Ron (dorunron)

 

Our levels are slowly going down. Not leakage, I think. More likely just evaporation. I'd concur: pre-mixed coolant. Would be nice if you could get a quart bottle... Maybe if you're DIY but ask nicely at service, they'll give you a pint?

While I'm doing my own oil and transaxle changes, I've pretty much made up my mind to let them do the coolant change (if I ever get there), so I don't want to be lumbered with most of a 4 liter container of the stuff.

 

I got a bottle of the Toyota coolant, but I regret that I put in some water once, before I got the coolant.

 

IIRC coolant exchange of the inverter circuit is a little less than a gallon.

As for the engine coolant circuit, I plan to replace a gallon every year/10k miles once the car reaches 80k miles. With a Lisle funnel I can avoid introducing air and the subsequent hassle of burping the system.

So a gallon container is actually a practical quantity

 

^ Are you thinking to avoid an all at once change thus?

 

I don't think you should regret that too much.
IF the loss really is just evaporation, the only thing you are losing is the water component.
I'm pretty sure that the coolant itself doesn't evaporate easily.

 

Well it wasn't evap I had the typical water pump leak but now it is holding

Gotta get me one of those li'l funnels...what is it?

 

Exactly. Or perhaps make it a once in a car lifetime annoyance. I'm not yet positive exactly in what manner coolant is 'old.' Does it mean contaminated, or does it mean protective chemicals have been used up ? If the latter then I'll just refresh a fraction periodically.

Lisle funnel. Google for an internet purchase, although I bought mine at a NAPA store locally. I think it cost $45, and it is worth every penny.

 

Check the PH. If PH is spot on then you should be fine. Check yours as well as ours should be spot on as well? H

 

I agree that if the fluid is acidic or turbid it is time to change, but I'm not sure if that is enough.

addendum: To clarify, I am unsure about the converse: I don't know if both pH and turbidity are within tolerance, if that is enough to say that the coolant can continue to be used.

 

Agreed on the PH Level. Also if the fluid has changed color from original, it is a good indication of contamination. Best to sample a fresh batch of SLLC to establish a baseline for the PH level, and the color of the fluid. The only other thing that comes to mind would be to run a sample through a lab for analysis while also furnishing a sample of fresh SLLC for comparison purposes. I also agree that the Lisle Funnel is the tool to have for those who are working with coolant changes. Less expensive than a air lift and seems to work better than a air lift. Plus there is no squeezing of hoses unlike with a airlift tool.

 

Hobbit wrote about engine coolant during his '100k' mile maintenance. His coolant was 150k miles old and had turned orange colored, but still tested pretty well by pH.

 

What I'll likely do is buy a gallon, top up the reservoirs, then when replacement interval comes up get the pros on it, and bring in the remainder. Maybe they can use, or at least recycle.

 

I do recall that "sage". It would be interesting to run a chemical analysis of the used coolant and compare to the new. That would be the tell all for sure.

 

Not sure what is "enough" ??

Draining out a bit and putting partial fresh only addresses part of the age problem.......depleted additives.....but not the other problems of chemical changes creating bad stuff and possible "grit" creation and accumulation.

A partial exchange is little better than just leaving it alone.

 

Right. Whether those two variables alone tell us when to change coolant. "Grit" will make the solution turbid. And as for "bad stuff," you will have to be more specific and show that serial dilutions leave too high a concentration if you want to taken seriously.

As for your other dogmatic statements, do you have any objective data ?

 

Give it a rest please.

Like everyone else here I am stating my considered opinion, garnered over about 50 years of experience.
I think the fact that ALL car makers recommend changing the coolant out COMPLETELY at some point in time, usually accompanied by a simple flush, is proof enough to me that other "plans" are either not effective or not necessary.

If you think the recommended change interval is too long, then change it earlier.

Do you use the "partial replacement" method for engine oil and brake fluid ?
If not, why not ? (No answer required; rhetorical question.)[/QUOTE]