2008 - Engine Coolant Pump Leak

Yeah your missing something alright even though you drew a red line around it.

Take the cap off the radiator and look inside it for gods sake. It’s probably almost empty.

Go to the dealer and buy 2 gallons of Toyota LLC coolant. Buy a funnel. Fill up the radiator to the very top of the neck. Buy the original water pump not a parts store pump and the origiinal water pump belt.
Amazon or eBay or dealer.

Bring all that stuff to your mechanic.

 

Engine coolant lose in any vehicle is not something to take lightly or attempt to milk. For the few hundred dollars it will take to replace the pump, belt, tensioner (yes buy one of those as well) and the coolant is far less expensive than installing a new used motor after you warp the head.

There really isn't a good early warning system for coolant lose in vehicles other than a visual inspection. Hooray for your mechanic properly alerted you to your leaking pump! By the time the idiot light for high ICE temp comes on, on the dash odds are its to late and the damage is done.

The red box is simply an expansion tank that allows the coolant to expand into due to heat and pressure, the tank is somewhere for it to go. Yes it should be filled to the full level but no it is not necessarily an indication of the coolant level in the ICE. The coolant tank adjacent to the inverter has absolutely nothing to do with the ICE's coolant level. While both circuits share the radiator as a common component to shed heat but they are on completely separate cooling circuits.

Open the cap under the circle and at the very least fill that until full in the meantime.

 

Penny wise pound foolish.

Leaks get worse overtime, and this will be the cause of an inconvenient stranding and possibly catastrophic engine failure.

The pump and coolant is cheaper to replace, NOW, than dealing w/ an engine replacement due to a catastrophic overheat.

Just change the water pump and engine cooling loop and be done.

An ounce of preventative maintenance (water pump & coolant), is worth a pound of cure (engine replacement or vehicle replacement).

 

Yes the cap in yellow remove it and fill the rad back up with Toyota LLC coolant.
For some odd reason the overflow tank level does not move. The rad can be empty and the overflow tank will still be sitting at the same level. Its crazy.

 

The rad level and the inverter coolant reservoir level should not move one drop. If its showing lower all of a sudden you have a leak.

 

1) Check by looking directly into the radiator. YES the radiator cap. Open when it is COLD; let the car sit overnight, check in the morning before driving off.

2) Overflow is full b/c air has likely gotten into the engine cooling loop, due to leakin engine water pump. Air prevents the system from being a closed system. Some coolant should flow into the overflow as pressure builds up due to rising engine/coolant temperature. As the engine/coolant cools, coolant should be drawn back into the radiator from the overflow. Air in the system prevents this from occuring.

Internet Search: how does radiator overflow work.
There are nice diagrams to help comprehend this process.

READ the owners manual; boring to read but useful info. It will increase your limited auto knowledge as some of your questions are well answered with nice illustrations.

 

A known leaking engine water pump, producing a visible spray pattern, for me would be an urgent fix.

Why? Leaks get worse over time. Loss of coolant could lead to an overheated engine and warped cylinder head. What was a $300-$500 repair (water pump, belt, coolant, labor), is now a $2k+ repair (used engine replacement). This is obviously a worse case scenario, that has occurred a few times here. An ounce of prevention (water pump replacement) is worth a pound of cure (engine replacement). Decision is yours.
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The leak sealing itself (TEMPORARILY) is possible. But it has already failed, and the leak will get worse in time.
Ask your mechanic if he topped off the radiator.​

$55.33 engine water pump at Camelback Toyota; some get greater longevity, others shorter longevity. Sorry, are on the short end.
$14.99 engine water pump belt at Camelback Toyota.
$33.90 (two gallons of SLLC at $16.95/gallon); Cabe Toyota in Long Beach; local dealer

$49.59 idler pulley (belt tensioner) at Camelback Toyota; optional IMO for you, if you wanted to save some money; FYI still on original bearing at 157K miles.​

$104.20 (most parts); $153.81 (ALL PARTS)

Call your mechanic and inquire about water pump replacement cost.
Call Avi at Hybrid Fix, near USC. He's a member here and posts occasionaly; very knowledgeable and competent for Prius repairs.

Engine loop is a harder loop to properly bleed trapped air. Mechanics not familiar with the Prius seem to not get it correct the first time.

 

Since you're in Torrance. Doesn't hurt to call Hillside Auto Repair (Hawthorne/Newton). I can't comment on their knowledge and competency, as I only know about their existence b/c of their mailers I get, saying they specialize in Hybrid repairs. They do have a new customer coupon ($25 off $100) and $20 coolant exchange, should you decide to go there (I would insist on being able to use both coupons, although they say you can't).

FYI, maintenance intervals are based on time/mileage, whichever occurs sooner. The 1st coolant drain/fill for BOTH loops (engine and inverter) is to be done at 10years/100K miles. Your mileage is inferred to be around 75k miles, based on post #1. Given your 2008 Prius (possibly purchased in 2007), you are possibly overdue (11 years old) or approaching the 10year mark (2018 minus 2008). Since the water pump is getting replaced, you may just want to have both loops serviced at the same time and be done. 5yr/50k miles becomes the new coolant replacement interval per maintenance schedule.

Ask Avi and Hillside if there is multi-service discount, which there should be. See what parts they use (OEM parts, Toyota SLLC). Avi is a known. Hillside is an unknown. You will have to decide.

Be happy your oil overfill did not result in catastrophic engine failure. Read this post: Another Walmart oil overfill, Toyota is hinting at new ICE | PriusChat

Be sure to check your engine oil level regularly, on level ground (every gas fill-up/weekly/monthly/etc) and top off UP to the FULL mark. You may find it easier to read the dipstick after the car has sat overnight.

Remember, the parts prices I listed are if you order or try to shop around and see if local dealers will match. Mechanics will markup their part price acquisition, as they have to earn a living too. But, you'll see how much their mark-up will be; minimum 50% is my guess.

 

You don’t need a specialist to change the oil but you do need to be in charge of the oil level.

Jiffy lube for instance in there records says the G2 takes 5 quarts.

So what you need to do is go to Walmart buy a 5 quart jug of Mobil 1 5-30 for $25 and then pour out 1.5 quarts of oil out of that jug into another container. Now you have a jug of high quality oil with the exact amount the g2 requires which us 3.5 quarts. You bring that jug to the mechanic this way you have circumvented
Any confusion. Make sure you get the empty jug back so you can use it as a container for the 1.5 quarts you removed and future exchanges of oil.
This is what I do when I Have someone else chnage the oil. Never ever any mistakes.

And the rad is full because your mechanic filled it up. Change the water pump and belt ASAP. There is no dash temp gauge in this car you will never know if the pump has failed till it severely overheats the engine and a check engine light comes on. Too late engine damaged usually blown head gasket. New engine time.