sudden head gasket failure - or something else?

I don't have the $300 or $250 manual set that may be next but then again maybe not who knows The section I read from the manual was what somebody else here copy down about the 5 hours after shut down and so on My pumps running just great It does exactly all of this but the car gets a code so I'm thinking it may be the temp sensor it's after 5 hours it turns on for a second to do exactly what does anybody know? My guess is to sample the temperature of the water that's in the CHS tank why 5 hours I don't know.

 

Well they'll be plenty of reading going on very shortly. A young lady about 3,500 mi away from me heard through the grapevine from other sites that I needed the three manual set for the '09 Toyota Prius and all its supplements she will be sending them to me free of charge needless to say I will be giving her a generous tip and a good thank you so I will have the hard copy in my hand soon I hope so I can read and not have to worry about finding crap behind paywalls to think the 2009 manual in 2023 or 4 is behind the paywall still holy Jesus.

 

5 hours after you park that generation 2 from a full warm up run that coolant heat storage tank pump should come on take a sample of water and shut off Is that happening only you will be able to tell so at 4 hours and 45 minutes after a shutdown walk out to the car sit on a milk crate next to where the fender liners removed and the heat storage tank is If you need to put your hand on the pump and verify that right at 5 hours the pump comes on? If that doesn't happen that's a clue The temp sensor that screwed into the side of the undamaged unmolested heat storage tank does it meet spec It's a pretty standard temperature sensor for Denso. Other than that there's nothing that really can happen to the coolant heat storage tank itself unless it's been pummeled in an accident there's nothing in it to just go bad so I have a car with this issue right now I'm thinking it's the pump I have not been able to go out and verify it that the fifth hour like I need to someone else drives the car it drives perfectly she just clears the code and moves on In the summer time this doesn't happen this is mostly a winter problem. I need to check the temp sensor also to make sure it's within the spec but if those two things are fine then I would think the computer that's controlling the pump maybe the issue but I'm thinking in my personal car that the other half is driving I'm thinking it's the pump itself I have two or three at the ready so I need to get out there and check it at the fifth hour see if it comes on in the morning when we start the car etc No one has done anything with it the car drives perfectly gets 48 mi to the gallon and win this CHS code pops up she has Bluetooth code clearing always on and she just clears it and keeps driving everything else with the car is spot on The only thing on on the dash is the tire light haven't had to change the tires yet to put the new sensors on this is the car we bought for $800 with brand new tires on it General something another the tires that is.

 

I'm confused. The original post talked about coolant in the engine oil, yet somehow the thread is now talking about the inverter coolant system.

Nobody has talked about the engine coolant pump, nor the tiny belt running the engine coolant pump. How did coolant get into the engine? Did someone cross-connect a coolant line to a crankcase ventilation line? Did someone try to add coolant in the wrong place, or take the thing canoeing through a puddle?

 

What code scanner gave you those codes? Most of them are not valid Gen 2 codes.

 

I agree. Holes in the block or hg that might connect a coolant passage to oil don’t just fix themselves. Either there never was coolant in the oil or somebody put it there and will never admit it. Maybe the op has an ex who doesn’t like him.

On the other hand P1151 and other codes should be easy enough to fix with the repair manual sections.



PDF

 

It seems to me I don't have all the literature to read just yet It's on the way. At 5 hours after shutdown the computer calls up the pump samples what's in the CH tank and if I guess it doesn't like what it sees when you come out and start the car whenever that is it sets the code because it didn't like the temperature of the water it's all for whatever reason that I can't answer but I can tell you that I have plenty of heat storage tanks sitting right here I'm staring at three of them I see no way without it getting smacked in an accident that the coolant heat storage tank would just be void internally that would be like my metal water storage tank for my well which does not have a bladder in it All of a sudden be not holding water and no way to tell where it went highly unlikely you'll be able to stand in front of that tank and find a hole or something it'll have to be on the ground whatever was in the tank same here if you get a chance to see a tank out of the car you will see what I'm talking about You can blow in and out of the passages through the tank very boring stuff but that's that The tank is double walled I think it is kind of like a yeti cup little thicker wall probably but that's about it so between the temp sensor and the pump and the computer sampling something that it thinks it doesn't want to be seeing whether that temperature is too low or too high or I have no idea.

 

The way I read the docs you have a bad storage tank unable to hold hot water for a length of time or there is an air lock caused by changing the coolant wrong. I suspect the air would be pushed through given a few cycles so that is less likely.

I think Toyota has enough tests to code on the other parts of the system. I would probably buy a used tank if they are expensive.

 

I would use a capable scantool and see what the system does during a cold startup. Normally the ECM adjusts the 3-way coolant valve and runs the CHS pump for several seconds before starting the ICE.

The CHS and ECT temperature sensors should go pretty high.

Here's a graph of some data. Cold start on a 40° F morning. I turn the car to "ignition on" (not ready). I turn off the HVAC - climate system. Then connect the scantool and select ECM data for RPM, CHS temp, ECT, (and coolant valve position). THEN go ready and watch / record the data.

I have fixed various problems with the CHS system, (CHS Temp sensor - wiring, incorrect hose routing, CHS pump - relay, 3-way valve) etc, but have never seen a bad tank.

Posted via the PriusChat mobile app.

 

You can try your adapter with CarScanner and see what the ECT (engine coolant temperature) does. You want to listen carefully for the CHS pump to run for 5 seconds or so before the ICE starts.

All of the "free" scantool apps I have looked at do not have Prius specific engine data. So there will not be CHS temperature (water outlet in my previous capture), or coolant valve position.

Here's a thread that reviews several apps and devices, including some that can scan all systems on a Gen 2 with codes and complete data.

I would confirm that everything else works correctly (CHS pump, CHS temp sensor, coolant 3-way control valve, and proper hose routing) before thinking about the CHS tank.

That said, it might take an hour or two to replace that tank.

https://priuschat.com/index.php?posts/3290690

Posted via the PriusChat mobile app.

 

CHS tank Will be a pretty easy job one of the easier jobs if you do a lot of work on your Prius break a couple of clips pull the fender line or back and do a couple of tens that hold the brackets in and the whole mess just falls on the floor Make sure you've unplugged your pump and your temp sensor so you don't jerk on the plugs and you're out of there going back in is just about as easy. If you're already missing your fender liner you're 10 minutes into the game or better so far I've replaced no tanks and I have about four of them sitting here unless they're wrecked visibly dented and damaged and they pretty much work It's a big yeti cup.

 

Tomorrow I should have access to a gen2 and will try to scan the chs system with Car Scanner. I know gen3 hybrid points are well represented in that app. Techstream is the gold standard and allows control of most actuators, pumps and the like so is the go to for most of us when things get serious. The app is great for a quick look anywhere by grabbing the $30 Bluetooth out of the glove box and connecting the phone. Techstream is more of a pain requiring a PC and hardwired adapter.

Because of the previous wreck and repairs there could be intermittent comm bus or wiring issues.

The fact you get multiple codes including P0003 and P1115 is concerning. Plus your codes can go months or years before returning.

I agree it would be better to see the coolant temp coming out of the tank after a cold start.

 

I checked a gen2 today with Car Scanner and found no points for the CHS system. One thing that is easy to notice is the pump runs immediately after shutting down with a warmed up engine.

Attached are the PIDs Car Scanner has on a gen2. They include most hybrid data.