Should I top of Coolant After a Drain and Fill? Service Advisor says no

This is when the engine is "cold", and not after it is at operating temperature?

There should be two sets of L and H marks on the coolant reservoir, one for cold level and one for operating temp level, after shutting down the car after it's been driven.

It's not unusual to have to add some coolant to the reservoir after changing the coolant. It would be more unusual for the coolant level to "go up after a few days".

Posted via the PriusChat mobile app.

 

This is page 373 of Prius c Owner's Manual; only one set of lines:



I suspect if you check the level when it's hot, then the next morning when it's cold, you'll see little if any difference.

It's not unusual to need a little "fine tuning". I'd call those guys again. If they stonewall, buy yourself a bottle of pre-mixed Toyota Super Long Life coolant (around $20~25 through dealership parts department), top it up yourself, don't use those guys again.

 

Lol...'advice' like this from service folks is why I do my own maintenance. Of course you can fine tune your coolant level....especially after changing it.

 

That's funny. It isn't uncommon for the level to drop some shortly after a refill, as some of the last dregs of air in the loop find their way out. It does not, however, then reappear and "settle back up".

Your car has two cooling systems, one for the engine and one for the electronics and transmission, and you haven't said which level you're talking about. The reservoir for the electronics is a whitish bottle with a pinkish fluid, way up in the middle of the engine compartment near the windshield wipers. The one for the engine is another whitish bottle with pinkish fluid, attached to the fan shroud just behind the radiator up at the front.

Other models from the Gen 3 era, the liftback and the v, come with a "degas bottle" style of engine cooling system, where the plastic bottle is part of the normal circulation, and it's the only place to check engine coolant level.

But your c still has the older, "overflow bottle" style of system. That whitish bottle behind the radiator is a kind of stagnant backwater and only serves to contain fluid that expands out of the cooling system as it warms up, and return it as it cools. Your cooling system also has a separate pressure cap, more like a traditional "radiator cap", only yours isn't on the radiator. It's on a little tee in the hose leading to the top corner of the radiator. From the very top of that filler neck, you should see a small hose that leads to the overflow bottle cap.

Now that things have settled in for a while, there is absolutely nothing wrong with (when the engine is totally cool!) taking off that pressure cap to make sure that the coolant level there is right up to the top of that neck, then putting that cap back on all the way, popping the cap from the overflow bottle, and topping that up to the F line. It ought to stay put from now on. (I am not aware of it being marked with separate marks for warm and cold; as far as I know, it's only marked for cold levels. I don't own a c so I could be mistaken.)

The reservoir for the electronics is simpler. It's the only place to check. If it has dropped a bit from F, there is no problem adding a bit more SLLC to bring it up, and it ought to stay put after that.

 

Ok, same deal. If that one has dropped a little, no problem with pouring a bit more SLLC into it to reach the F line, and it ought to stay put after that.

While we're at it, how is the level in the reservoir behind the radiators?

 

In the foreground here, you can see the pressure cap (shiny metal cap with yellow label, on a black fitting between two hoses), and the black plastic reservoir cap on the white overflow reservoir next to it.

The narrow hose leaving the pressure cap fitting to the left ought to end up at the overflow reservoir, though it isn't easy to see in this photo.

 

Two steps. When the engine is cold:

Open the shiny cap, look in there. Coolant should be right up to the top of the neck where the cap gasket sits. If not, add some coolant. Put the shiny cap back on. Be sure to twist it clockwise all the way.

Now check in the white bottle right next to it. Is that coolant up to the FULL line? (See the drawing Mendel posted in #3.) If not, pop the black cap off that bottle, add coolant to the FULL line, put the cap back on.

While you are there, it should be easy to confirm that the narrow little hose from under the shiny pressure cap leads to the white bottle.