Need help! Gas engine overheating. Cannot resolve.

The pump is electric. The dealership told me the parts numbers for 3rd and 4th gen were different, so they assumed they weren't compatible. First time they explained this to me they said the spline on the pump was too thick. Next time they said it was too long. It was the service manager relaying the tech's diagnosis to me. I initially had a 3rd gen pump on the engine, but it burnt out and gave a code P261B (I think, I didn't write that one down.. I am going from my search history). I then switched the 3rd gen pump out for the stock 4th gen pump and the code went away and it ran okayish for about a week (though I could only drive a few miles before it got up to 230 - enough to get to work and back). Now the 4th gen pump has the P148F code (and loud noise) as of today. I cleared the code and it has yet to come back, but it still is making a noticeable loud noise (video above) when idling. I haven't tried to drive it again.

I don't have TechStream, but I do have a OBD device that I use to monitor temperatures.

 

I wonder what would cause a P148F code in a water pump with only 47k miles? I've read some on this forum speculate that it is due to an electrical cause. The OP had this code as well, though he simply replaced his water pump and purged air and we assume that his problem did not return, indicating that his P148F was likely not a problem with the electrical system. I am wondering if my pouring coolant down the port of the coolant temp sensor above/behind the egr may have caused this? Perhaps the readings were thrown off and the ECU directed the water pump to run at high speed. Does P148F necessarily indicate a broken pump, or just that the pump was running at high speeds temporarily? Or does the high speed alone indicate the pump being broken?

 

Thanks for clearing that up: it was you divulging all that info. My memory sucks. Anyway: I wonder what @Ragingfit did with his transplant. Did he use the 4th gen water pump, or transfer over his 3rd gen.

Just a hunch, and I think you've run through all this already: there's something different enough with the 4th gen pump it doesn't play nice with 3rd gen ECU. Or maybe it does. If your third gen pump is toast, it's an expensive gamble to buy another third gen pump, only to find the problem persists.

 

What is the optimal RPMs of the water pump? I just put mine is maintenance mode and ran for several minutes and it maintained around 2250 rpms. Is there a website where I can find optimal values for various sensor readings? I have enjoyed my OBD tool, but without knowing the optimal values I feel I'm under-utilizing it.

 

You need to know how fast the pump is turning and if it's drawing too much current, or if it is NOT
drawing enough to turn fast enough, thus burning out. Maybe the wiring harness is pinched.

You really need TechStream to test the water pump. I can't remember anyone using anything else.
I could be incorrect, I just don't remember anyone saying anything about it.

You said it's noisy at idle, so it goes away when the engine stops?
Very strange 2 pumps go out so quickly. Seems like maybe something else is going on.
AND it's overheating? Probably because the pump is not working correctly. Or the thermostat is not
opening. Did you replace the thermostat?

Hard to diagnose without the proper tools.

 

I replaced the thermostat as well. My main reasoning for having not bought Techstream at this point is that I have read that you have to operate an older system of Windows, and I would have to borrow someone else's laptop, and would rather not install older operating systems on their laptop. Also, I've read too many bad reviews of people getting viruses from purchasing it off Amazon or eBay. I may need to just take my chances if I'm going to diagnose this problem.

Well, when I said "idle" what I really meant was the ICE was off, but still in ready mode. After driving home, with the P148F code, the pump was loud. I deleted the code and every time I've started it since I have not heard that sound.

From what I can tell, the coolant hose leading to the heater core is hot. I wouldn't think it would be if the pump were not operating. Also, the hose leading away from the heater core is warm (not as hot as the one leading to it, though I've read that's common).

I can take my multimeter and test the water pump sensor tomorrow.

 

don't know if my recent experience helping your situation. But thought I would share..

I recently had an overheating issue and it was the water pump. It made loud noises before it was totally seized, and I ended up replaced it.

After I replaced the water pump, I found that engine operating temperature is on the hot side. Never overheating, but around 199° and flirting. That's when I found the radiator hose from thermostat to radiator doesn't get hot like rest of the hoses, and it actually quite cold in comparison..
With the help of this forum, and after multiple attempts of asking questions and research I finally figured out!

The fix was bleeding out the trapped air at the top by temperature sensor, the trapped air I thought I had bleed out already, and turned out I didn't do a good enough job..

It's easier to bleed air out of a 2010, because of the bleeding valve. But there's a thread where the bleeding valve wasn't available, but by removing the temperature sensor to let air out while engine is running at temperature did the trick...

I hope this bit of info provide some help.. good luck!


Posted via the PriusChat mobile app.

 

My son had a a laptop he didn't need any longer, his wife used it for classes.
So I got mine for free.
I ran all the updates. What a royal pain in the butt! HORRIBLE! That thing rebooted
more times in one day then all my Mac together for the last 10 years!
I finally contacted the people I bought techstream from and they logged on and got it
working. Took them 3 or 4 hours! Another nightmare!!!
After that, I turned off wi-fi on it. It has not been on since, about 2 years.
And that is the only thing installed on it, it's the only thing I use it for.

You could try a pawn shop, or craigslist and find an older machine to use.

And I would not remove anything connected to the coolant system while the engine is running,
and hot! But it's YOUR skin!
You can remove the highest hose while you fill the system slowly. When you see the coolant
leaking out, re-install the hose, tighten it, then finish filling the system.

 

Things break.
Obsessing over knowing WHY will make you crazy.

 

I have done 2) swaps into 2012 Prius v's. You know about the second one cause you saw the video. The first was my Black v. I used an engine from a 2016 with 3200 miles on it. It was my first and I had to burp like all Prius', but it would overheat occasionally for a number of weeks.
I put my scan tool on it so I could see what temp I was running. You don't need a scan tool - light flashes at 240, light stays on over 250.
The Black v settled in and is fine with no overheating. The Gray v went very much the same until I replaced the coolant in the winter. It overheated every day on the way to work, all winter. Very stressful. I think air would get in the thermostat housing, insulating it, keeping it from opening. Why every day, 10 miles in, right after I went through the toll booth? IDK. I would pull over, add coolant and it would be fine for 35 miles.

I tested everything by eliminating them from the system. I concluded the heater core was restricted. I'm not gonna' replace my heater so what I did was cut the jiggle pin out of the thermostat. I drilled a hole in one first, but that makes 2 holes including the jiggle pin hole.
My Gray v HAS NOT OVERHEATED SINCE.
Cut the jiggle pin. It keeps the coolant flowing over the thermostat. When it gets hot it opens. No more overheating.
It takes a bit longer for the engine to warm up when it's cold out. That's the only drawback. You can put in a new stat if you change your mind.

 

Today I drained all of the coolant and then removed the water pump to inspect it. I really can't tell a difference between it and a new one - it spins like it should, and has the appropriate amount of resistance.

I'm going to assume that the P148F code doesn't necessarily indicate a broken water pump, just that there was over revolution at that particular time, perhaps at the directive of the ECU due to overheating (?).

I'm going to refill the system with coolant and this time follow the advice in this thread about removing the temp sensor above egr to allow an escape route for air. Hopefully this will fix my problem. Will update.

I am somewhat relieved to hear that overheating is a common problem after refilling coolant, if for no longer than a few weeks. I may have to bleed air several times as the air works its way out.

 

Is the temp sensor what was also the bleed valve then? I wasn't clear on that.

 

A temp sensor is located beside what used to be a bleeder valve on 2010's-11's. Mine is a 2012 and it's closed off and serves no function. From what I can tell, the temp sensor port is the highest point in the cooling system (at least if you jack the front of your car up). Once you fill your coolant to the point in the picture below, raise the reservoir until coolant pours out over the temp sensor port, then close it off by screwing the temp sensor back in and put the reservoir back. That guarantees that there is no air in that line. Before I attempted this the coolant was up to the full line in the reservoir. I dumped the coolant in two empty containers. After pouring the coolant back in the system (with temp sensor port opened) the same coolant was around a couple of inches below where it was before (picture below). From there to the full line is how much air was in my system before. I then squeezed the lower radiator hose a few times to force coolant through the radiator and it went down a few millimetres more. I've yet to take it out to drive.. I'm still researching water pump specs.

I rotated the plastic piece that the temp sensor is located on, so that the sensor port would be oriented vertically. Not sure if that makes a difference. Oriented vertically, it is a little higher than horizontal.

 

I ran the car in maintenance mode, after refilling the coolant with the above method. I've never kept track of water pump RPMs until now, so I'm not sure what I should expect. It stayed around 3300 rpms until it hit 180 degrees(f) then it went up to 4000 rpms. I still do not have a P148F code. Not sure how high the rpms have to be to trigger that.

 

That's a good sign.

 

I hope this cures your problem.
Filling slowly helps a lot. But taking the sensor out certainly helped bleed the air out.

 

Took it for a test drive. It didn't spike up to 240 degrees within a mile, so that's good. However, it still hit up to 215 degrees after several miles of driving (with acceleration). It seems the average is around 200-210, so I wonder if there is still a small amount of air left to bleed. @Ragingfit has stated that it's not uncommon to have mild overheating for the first few weeks until it settles in. I am hoping this will be the case with mine.

However, I did notice that once the temperature rose above 200, the water pump was hitting 6000 rpms, and would periodically cut out to 0 rpms (only for a few seconds). It didn't seem to matter whether I was accelerating or not when the pump cut out. I'm not sure if this is normal, as few post about their normal water pump RPMs. I checked for codes again and have none. There is another thread (Water pump failure Symptoms | PriusChat) where this very same thing is discussed. @m.wynn notes that it sounds like an electrical problem, perhaps with the harness. That may be my next course of action is to replace the connector that attaches to the water pump. This would be the second connector I've had to replace since doing my engine swap (the other was a camshaft position sensor connector). Perhaps I was not as gentle with the connectors as I should have been. I also used dielectric grease on every connector. Maybe that was not the wisest thing to do?

 

That's pretty hot. Maybe still some air in the system. Did you replace the thermostat or reuse the
one that was in it?
You really need someone with techstream to test the waterpump. You keep replacing stuff, but haven't
verified if the pump is good or not.

 

I replaced the thermostat last week. I'm really leaning towards the idea that there's still some air in the system (though I'm probably biased). It's demonstrably better than yesterday, even with the wild readings on the water pump.

 

Better is good. Once you are SURE the air is completely out of the system, and it's till getting to hot,
find someone with techstream.... Don't know what area you are in, but there is probably someone on
Prius chat near you... And test the water pump.