Need help! Gas engine overheating. Cannot resolve.

@ASRDogman I bought this used not too long ago. Hence I am not familiar with the history. It was indeed a bad decision to buy this car, already wasted around 6 months troubleshooting issues with no positive results. I guess I will keep troubleshooting, and one day I will be able to drive it ... Thanks for your suggestion!

 

I would wait on the egr valve until you get a better idea about this engine.

Keep in mind you could get a guaranteed used in Japan (JDM) engine with accessories for about $1k from "JDM Place of Houston" located in NW Houston. 713-742-5000

You could use distilled water for testing and then drain at least a gallon and fill with Toyota concentrated coolant.

 

Okay, so I take it that it was NOT running, running correctly?

That is always risky. You should do a lot of research on what the cost's of repair
will be.

Despite what some say about the 3rd generation Prius, it IS a good car.
And just like any other car, there will be cost to keep them running and repair them.

And not knowing how the Prius works makes it more difficult for you. And you have to have
the proper tools to work on them and repair them. And those tools cost money.

If you are patient, and go step by step, you will eventually figure out what the issue is.
I do believe it is something simple, I could be wrong. But from what I've been reading on here,
it usually is.

 

I don't see why a water pump or thermostat would make a car run like that so before I spent money on new ones I would try to figure out the misfires. Just don't run the car long enough to overheat it.

The P0101, the recent work, and the fact that earlier you said giving it gas helps smooth out the engine... would have me looking for a potential vacuum leak. You may consider pulling out the air filter box and properly examining the intake manifold.

Next would be looking for liquid in the cylinders with a borescope.

After that I would pull the valve cover and make sure the timing is correct.

 

You're spot on! The issue is 100% Water pump. Today I removed both water pump and thermostat. I could barely rotate it. Thermostat - I am not sure if it is faulty. It looks ok. Below are couple pics. Is there a way to check thermostat? I also removed cooling fan relays, all three of them. When I used multimeter to test them, all three looked fine. So, not sure how to diagnose radiator fan issue? Could it be Cooling fan switch/sensor? Do you know where is it located? I googled and tried to find troubleshooting method and location of the switch/sensor but have not come across any useful info yet.

I had thought about replacing engine couple months ago, just nervous about it since I have never done it. I have watched many videos, I think it may be possible. Before deciding to do that, I wanted to rule out other parts. Are you in Houston? Which part?

Now, I need to decide whether to try replacing water pump and thermostat or just replace engine (knowing that both components will come attached to JDM engine). If replacing the water pump and thermostat makes the car drivable, it'll definitely be worth it. Otherwise, I'm not sure ...

Thanks so much again!

 

Great suggestions! Please check post #265. One of the issue is definitely water pump. What you suggested is lots of work for an unexperienced person. But I guess I will do it patiently. At this time, I am trying to decide whether I should try new water pump first or simply replace the engine. Thanks again!

 

Thanks for encouraging me! Today I found out that one of the issue is water pump. Please check post #265.

 

since you have the thermostat out, you might as well replace it.
With a Toyota OEM part. Same with the coolant pump.
Yes, they cost more, but you know they are the correct part and not chinese copies.

When you fill the coolant, go very slowly, only a cup or two at a time. And wait 10-15 seconds,
then add more. That will allow the coolant to push the air out. It will take longer, but you won't
have to waste time and fuel trying to get the air out.
Fill the tank to the "B" mark.
Then start the car, and wait for the engine to start, and wait until it shuts off on it's own.
Then check the tank, it's probable close to the full mark, top off if needed.
Then drive the car for 10 minutes and try to keep the engine running. Return home, shut it off, park it as
level as you can. Then clean up and check the coolant level. It's likely at the full mark. I like to put it
just over the full mark so I can see it. It will go up and down as you drive it.

The coolant fans probably didn't come on because the coolant pump wasn't circulating the coolant so the
sensor never got hot enough. And even if the did, it wouldn't help if the coolant isn't flowing.

I'm glad you found the issue!

 

The cooling fans should operate with the ac regardless of coolant temp.

The fans are ecm controlled using the engine temp sensors you know work because you were reading them.

It is most likely one of the fuses or relays here assuming the fan connectors are attached.

No I am not in Houston but almost all big cities have JDM engine distributors. I looked them up, called them to verify stock and price - all in about three minutes.

Given you have the water pump out I would change it with oem. Most likely the thermostat is ok but you could take it out and watch it open in hot water.


A new water pump is a good idea even if you swap engines.

I suspect there are still engine problems but you should fix the cooling and see where you are at.

 

.The thing about jdm engines, you do NOT know what you are getting.
You could be getting another engine like what you have now. There is no way to check
the actually miles on the engine.
There are places that at claiming they are jdm engine, but aren't.

The better thing to do is getting a remanufactured engine.

 

Actually you can tell if its a jdm engine by the model plate.

Look for X2ZR-W20 on the engine instead of your engine’s X2ZR-W25. The injectors should be tan rather than blue. tthe US engine's pulley is grooved for a serpentine belt (w no belt used), the JDM's is smooth. Both are used as a harmonic balancer. A JDM engine's flexible fuel line is a smaller diameter at one end. Replace it with the original line.

When you have a number of JDMs to choose from, look for obvious shipping damage incurred during the long transport and salt air transport from Japan. Some aluminum oxidation is ok. Bring a big ratchet to turnover the engine by the crank bolt to choose the engine with the best compression.

You do get a warranty long enough to verify operation and test for excessive oil burning, a rare occurrence on a genuine jdm with far less than 100k. You might think you have Mendel's pristine garage queen.