45k miles, low coolant levels?

anyone know what the shelf-life of an open container of the toy sllc is?

 

Yes its best to drive around with low fluid in addition to having pad wear because its designed like that.

And the coolant mixture is such a highly scientific thing that the slightest water evaporation requires you to add distilled water.

Where do you come up with this lunacy?

 

If you keep your brake fluid at max level for 'safety reasons' and you develop a leak, you have at best a few more brake pedal strokes before you get the Brake Warning light because your brake fluid is low.
After that it's Emergency Brake time!

You can keep your brake fluid at max. But what do you do at brake pad replacement time?
There is a Min - Max line for a reason.
Also, every time you open your brake fluid reservoir you allow moisture and possibly dirt to enter. I recommend not messing with it if the level is between the lines.

Is SLLC a full strength anti-freeze that should be cut 50/50 with distilled water before use, like most?

If you test the coolant in your reservoir and it's good to -50°, or such, do you really mess up the protection number of the cooling system by adding a few ounces of distilled water to the reservoir?
Keep in mind, this level rises and falls with each hot-cold cycle of the engine. So the reservoir and the system mix and have the same solution.

Yes, if you leave a container of proper 50/50 antifreeze open to the air, the water is what evaporates.
(Keep the dumb dogs and wildlife away from this test)
You can add distilled water to bring it back to 50/50.

I guess I pull this lunacy out of my,,,, pants. But they have a lot of diverse maintenance and engineering experience.

 

Under this scenario how well does this "safety reason"work if the reservoir is already low? I'll take the few strokes over none anyday.

At brake replacement time most people bleed there brakes also. If the car has run the pads down so low they need replacement at the minimum I would pull the calipers and re-grease the slides. And bleed the brakes.

Alot of diyer's here sneak new pads into the calipers even though the car is way into 150K+ miles and do nothing else. Most professional mechanics would not do that.

 

Your fluid levels should be low when cold. The cooling system has sucked back the excess fluid expelled when the engine is hot. It doesn't pay to overfill the fluid containers. If the fluid is below the low mark when cold then just add a bit until it's less than halfway between full and low.

 

Ok from page 406 Prius Owner Manual:

Look at the see-through coolant reservoir when the Hybrid system is COLD.
Should be between the Full and Low mark.
The coolant level in the reservoir will vary with Hybrid System temperature. However, if the level is on or below the LOW line add coolant. Bring the coolant UP TO THE FULL LINE.

 

Just pays to read the manual.

 

What happens when you bring the level up to the FULL line with the car at very low temperatures?

That manual in not infallible.

Does anyone know the answer to this question:
Is this SLLC a ready to use coolant, or does it need to be diluted 50/50 with distilled water?

(Also, just to stir up the faithful, Do you really need to use only Toyota's coolant in a Toyota, VW's coolant in a VW, etc, etc,? I'm pretty sure all car cooling systems have aluminum, cast iron, plastic, rubber hoses, seals, etc, in contact with the coolant. Why can't you use any high quality brand of coolant, you know, the long-life stuff? )

 

Both of my coolant reservoirs are at the FULL line when cool. I see very little movement when the coolant is up to temps.

Ready to use.

I would think you could use any coolant that matches the Toyota spec. Since the coolant is not changed that often I personally plan to use the Toyota SLLC. Same for my wife's Honda, I will stay with the Honda coolant. The savings for using Brand X is just not worth it to me.

 

SLLC is ready to pour.

I see none to very slight movement in either of my reservoirs between cold & operating temp. None actually in the Inverter. Which is why the full line is almost to the top in the Inverter.

Full line is halfway up the overflow for the ICE. Like most cars.

Easiest to track any tiny leak if you always keep it all full line when cold. Highlight the full line level & word with a black sharpie. Just look at it cold if its off the full line oops you are weeping somewhere. Changed out my ICE coolant at 35,000 miles and brought it to the full line. Hasn't moved off that line in 25,000 miles. If it ever does I look at the water pump for weepage. No evaporation going on there for 2 years now.
Exact same for Inverter tank.

Always at the full line at cold in all my cars in all my years. Most cars the coolant overflow tank full line is no where near the top. Plenty of room to move around.

 

I based my advice on what I had seen on other cars I have owned or helped with. I have seen over flow tanks split from excess pressure but more often the cap pushed off and coolant dispersed throughout the engine bay. It is apparently not a problem with the Prius. It has excellent reserve capacity built into the coolant reservoirs and it also does not usually run as hot as conventional cars. I have never seen my Prius temp over 93 deg C and usually runs at 91 or less. I am more than willing to accept the manual's recommendation in this matter.

 

Just for the record, these reservoirs are not under pressure in the Prius. They are vented to the atmosphere.
Hence, my earlier comment on evaporation.

Some cars have a reservoir that is directly part of the pressurized cooling system ( VW, Audi ).
If people are not having a problem topping the non-pressurized Prius reservoir while cold, then carry on.

 

OK, I apologize.
I was totally wrong on the Prius reservoirs.
The caps are the pressure regulator for the whole system.
Evaporation is not an issue, there is no 'breathing' to the atmosphere with each hot-cold cycle.

Although I still think it is safe to top up a low level with ~1/2 cup of distilled water.... in most locations...

 

Those split tanks were probably caused by LOW coolant levels and temps high enough to boil the coolant. Additionally, the pressure cap to vent excess pressure at 15-20psi or so. Splitting tank=possible malfunctioning cap. Fluids for the most part do not expand and are incompressible. It's the air space in your coolant system that allows a place for steam to build up and increase the pressure. The reason there is a full mark that is shy of topped off is to allow for burping of a minimal bit of air pockets to travel to that space. This has the additional advantage of allowing cooling systems on cool down to suck needed coolant from the overflow tank bringing levels back up if they've dropped due to evaporation or boiling off.

 

The ICE of a Prius runs the same temp as any other car, 93°C - 195°F. That's the T-stat spec.
Those are not overflow reservoirs. They are the high point in the coolant system. Instead of a conventional radiator cap, the smaller plastic caps are the pressure cap for the entire system.