Coolant refill after engine overhaul

It is best to fill first, as well as you can, then continue to add coolant as air escapes while warming the engine.

By searching this site you may be able to find a download of the repair manual, or perhaps just of the section in the repair manual for coolant refill. That would put you in the best position for a successful outcome, and you can be looking at the manual without having to wait for someone writing a description. The process is somewhat elaborate for getting all the air out, and the repair manual will show you the details.

 

The struggle with a full coolant dump is air will get trapped in the coolant thermos. This makes it very difficult to bleed.

It is very important especially for you that you monitor engine temperature during this process. This engine has a aluminum head and will not tolerate an overheat. Since no dash temp gauge it requires an OBD code reader that will read engine temp during this process.

what must happen for correct bleed process is to manually run the thermos bottle pump that way air trapped will be pushed along to the rad with the cap off and front end highly elevated. Front end elevated higher than rad top higher than the engine head as air gets trapped in there too.

Bottle motor is manually run by removing its relay and using a jumper wire turn on that pump at intervals with engine running in inspection mode.

aGo on YouTube search

Prius inspection

it will show you the chicken dance to get the engine to run in inspection mode
Where engine idles continuously.

Good luck this job sucks.

 

Here's repair manual info:

 

You can use a vacuum tool to fill the system without any air bleeding. Airlift is the best but over $100. Here is a similar one of under $40.
Auto Car Radiator Pressure Tester Vacuum Purge Cooling System Refill Tool Kit US | eBay

 

I bought one and still have it, but have gone back to filling and burping the old fashioned way, which hasn't really been any more trouble, and doesn't need me to lug a compressor out.

There are some subtleties if you go the vacuum tool route. Make sure your coolant supply jug is above the system, and that your tube from the jug to the fill fitting is already free of air. If the capacity is more than one gallon jug, combine the coolant first in a bigger jug, or watch like a hawk not to suck any air at the end of jug 1. Plan on no do-overs. If you get a partial fill on one attempt and then you try to start over with vacuum, the volume decreases as the hoses collapse and your partial fill sprays out the venturi. So a do-over means you drain the system again, then do over.

On the bright side, i have found the vacuum venturi handy for lots of other stuff.

 

The euro spec Prius does not have the coolant thermos, so it is possible that his Prius also does not have it. That makes it easier, but it still takes a while to get all the air out. Just a reminder, carry on.

 

What other differences the Gen 2 European Prius has? I have noticed that the steering wheel right buttons are not there. I also read that there are disks on rear brakes.

 

Steering wheel buttons depends on trim level and options. I think I have pretty much everything and all the same buttons.

It has rear disk brakes, and also rear drum brakes which are used only as parking brakes, actuated only by cables.

It does not have the eccentric mechanism on the windshield wiper.

It has simple halogen H4 bulb headlights.

It has an "EV" that button prevents the gasoline engine from running under certain, very limited, conditions. (warm engine or press within 10 seconds of cold start, max 50 km/h, low power demand, battery not too low or too cold, etc..)

It does not have an instrument lighting dimmer wheel. It toggles through 3 brightness settings by pressing the rightmost button under the touchscreen.

It has only the normal main engine air intake filter, not the second, additional, charcoal filter in the air filter housing.

Probably a couple more things I can't remember at the moment.