Massive Coolant Leak!!! Please help. (Now $4,000 Engine Repair!!!). Fixed! (Post #48)

If you are using an android phone or tablet, you can use the Veepeak Mini Bluetooth OBD II Scanner for Android ONLY which is $14 on Amazon, and an app like Torque, or Car Scanner ELM OBD2, or Hybrid Assistant to monitor the engine coolant temperature.

A different option is to buy a display unit, which plugs into the OBD2 port on your car, to monitor the engine coolant temperature. The one I bought was recommended by rjparker. It is sometime referred as a P10 display unit. Here is one listed on eBay for $33.

 

That's a great tip for monitoring coolant temps. I love my coolant temp display in my 2014 Tundra and don't understand why Toyota wouldn't have it in ALL vehicles with ICE engines.

 

#1. Are you sure the head gasket is leaking coolant?

#2. Coolant pump is likely bad, but it's not over $250 when order online from a Toyota dealership. And a fairly easy job to DIY...

I did not read where your car has roung start, so you might be able to drive your car for a while after replacing coolant pump.. because head gasket may or may not be an issue..

Posted via the PriusChat mobile app.

 

Well first off I wouldn't get carried away with the water pump replacement is being the end-all be-all I forgot what your mileage is but this engine is known for overheating and head gasket problems but that's usually starts with rattling at startup and then more when driving as it gets worse but anyway I'm glad you for now have solved your problem with a water pump just beware and be proactive that this head gasket issue is quite normal in this vehicle at certain types of mileages I've had two of them so I have a little bit of an idea of how it will go. Do you have your old water pump does the impeller spin freely when you spin it just curious if you take the four bolts and take the backing plate off and lift the impeller out Is it all chewed up plastic? Which is kind of things you want to know with this particular model. But maybe the pump has been left where it was removed so on and so forth can't be looked at now who knows.

 

Did you replace the engine water pump yourself, or did you pay a mechanic to do it?

What engine water pump did you buy? OEM or aftermarket?

Did you use new coolant, or did you reuse the old coolant?

 

It usually goes like this

Failed water pump
Overheated engine
Blown head gasket
Coolant leaks out

a failed water pump usually would not cause your coolant to leak out. It may only seep out a bit, So you might have just put a band aid to fix your issue in replacing the water pump

 

Yes that was a bad impeller apparently now we can buy the impeller for the water pumps on Amazon or eBay for like $35 then if you to undone the four bolts or you can remove the impeller It's just a magnet like a washing machine impeller a mag drive type impeller The plastic swells up from the heat of the coolant or overheating coolant what have you splits the plastic makes it hard to turn replace the impeller plug the pump up before you even bolt it to the car boot the car watch the pump turn call up the speeds from tech if you like see it work bolt it back on off you go maybe you saved it because some of the cheap imitation water pumps will fail very quickly and if you have your old one you can just put an impeller back in it if that should happen and maybe be good for a while It seems the electronics in the seconds or lesser made water pumps just aren't up to snuff apparently they look good but they don't work well.

 

Has the miles on the car been mentioned?

EGR and intake manifold ever been thoroughly/completely cleaned? If so at what miles?

My 2 cents, if it's a gen 3 with 150K+, and the aforementioned cleaning was only recently done, or half-@ss done, you're in a fool's paradise to think the water pump is your only problem.

BTW, with head gasket failure coolant does not typically leak into oil; it leaks into combustion chambers, typically cylinder one or two, leaking at the adjoining wall.

(Damn, 'nother case of OP starting a new thread, continuation of the other thread he started. I've reported, @Tideland Prius may merge this one.)

 

I do not agree with your order of events. Based on reading many Gen 3 engine overheating problems in this forum over the past 3 years, I have concluded the following order:

1. The engine coolant pump begins to fail. The white plastic which covers the magnet on the end of the impeller splits. This causes drag and the impeller can not spin at the speed that is requested from the ECU. The flow of coolant through the pump is not high enough to cool the engine.
2. The engine overheats and the "High coolant temperature warning light" will come on if the sensor detects the coolant gets to 120C (248F).
3. Pressure builds up in the cooling system and coolant is pushed past the cap on top of the reservoir.

The overheating of the engine will occur during periods of high throttle usage, like highway driving more the 60 MPH, driving up a hill or mountain, etc. Sometime you will get a trouble code P261B and sometimes you will not get the trouble code.

There are also other failure modes for the water pump besides what I wrote in #1 above, but an overheating engine can force the coolant out of the reservoir without having a bad head gasket.

If the problem is detected early enough (before the engine severely overheats), I believe that you can replace the water pump and you will not have a problem with the head gasket. Most times the problem is NOT detected in time and the engine severely overheats which will lead to a head gasket failure. Only time will tell if the OP replaced the water pump in time.

I believe that the high occurrence of head gasket failures in a Gen 3 are caused by bad water pumps and overheating of the engine. So, I have been monitoring my engine coolant temperature staring 2 years ago. I now have 140k miles on my 2011 Prius, and I hope that I can detect that the water pump is starting to fail before I overheat the engine. Below is what I wrote on the OP's previous thread:

 

The water pumps are failing, but they aren’t the only culprit. I don’t think the engineers anticipated EGR passages choked with carbon.

 

You may be right about the pressure building up but not sure I'm convinced this is not a failed head gasket case.

If you are at 140k miles on your car, you should replace the water pump and not worry about it failing. This replacement is normally a 1 time replacement for most owners. I don't see many owners going to 300k with their car, so a second replacement is probably not going to happen. So it is better to do it early, since it is going to require 1 time, either now or a risky later time. Also these temperature readings you're looking at is from 1 place of the engine, the place where the sensor is at. The variable speed water pump does not do a good job since the engine temperature may be hotter in different areas of the engine and the water pump is not operating at a speed that will cool the hotter parts.

 

This.

 

It sounds like you bought a genuine pump at $200. There are counterfeits that fail in a few months.

Don’t get too emotional invested in a gen3. She will break your heart again and again. She is “high maintenance” as we used to say in the dating world. Keep throwing money at her and her shapely body will keep you coming back for more.