I've swapped My prius 2016 engine (had 330k) with 2019 engine with 20k miles. Old Engine problems: The old engine was overheating as well, I replaced waterpump & thermostat on it and also bypassed the catalytic heater exchange. I had used Bar's Head Seal and cleaned with Ironite TheroFlush. New Engine: It's from '19 with 20k miles. I put new water pump but kept the new engine's thermostat and coolant sensors and the EGR. Now even with the new engine, it's overheating and spraying coolant all over the engine bay. I noticed even while engine was above 200F the engine fan's are not running. These are some tests that I run with xtools d7: - Engine Fan Low & High modes are working when I commanded from the obd tool. - Water pump RPM is also responding properly from 0 to 3000 - heater works and AC doesn't have freon yet so it doesn't work now. - I've replaced the engine coolant reservoir with the one that has a bleeding hex bolt some of the gen4s don't have bleeder valve on coolant reservoir. I've ran out of ideas what could be wrong and not sure what to test now. Any ideas what could be wrong?
Winner, Winner, chicken dinner!!!!!! That Bar's head seal not only seals head gasket leaks; but they plug up any narrow passages (ie. radiator cooling, and heater coils). Did you replace the radiator when you dropped in the newer engine? Could some residual "stop-leak" have jammed up the thermostat? Check/feel the hoses for flow. What are the temperature sensors readings going to the cars CPU? I know the fan activation signal is way below 200 degrees.
Seems like my heater core was clogged. I bypassed the heater core now it seems better. I’ll drive tomorrow more to see if that was the problem. I didn’t flush the system before the new engine. I should have done the flushing. Better late than never
I noticed the passenger side of the heater is not pushing hot air like the driver side. So this could support heater core clogged assumption?
I just did a test drive after bypassing the heater core still getting overheated. I had connected the 2way obd tool during the trip and the fan is not spinning even when temperature got above 225f so I had to turn on the water pump to max rpm and engine fan to high manually via obd tool. so now next option is to flush the system from bars head seal residue. Will it clean the coolant passage from engine as well?
Engine coolant passages are larger than radiator- or heater- coils. If the heater coil is blocked, there's a good chance your radiator is too - about the same size passages. Your coolant thermostat probably isn't engaging the fans because of insignificant coolant flow - it doesn't see the true coolant temperature. An IR temperature gun would confirm. hit the 4 corners and center of the radiator; all temps should be the same. Any cold or hot spots is a clog. Make sure your electric coolant pump is working. Also, if you car has an electronic coolant diverter valve - check functionality - it may be stuck diverting all coolant to the heater; not allowing any coolant to the radiator. hope this helps
50/50 water/vinegar “may” dissolve your stop-leak product. One such product manufacturer recommends it. Test on a “chunk” if you can extract one, say from the reservoir. Some more thoughts on how to do such a flush, and return the system to a 50% coolant mix, in my signature.
Many years ago I purchased a radiator power flushing kit that was marketed by Prestone I believe. Came with a tiny jug of the flushing fluid, A water hose T fitting that hooked to a heater core line, and a spout to connect to the radiator neck to divert water away from the car. I was expecting the system to be very dirty and hooked everything up an tried it without the flush chemical first, Got some of the junk out but nothing like what came out after putting the flush chemical in. Each time you powered up the hose, there was lots of flow and lots of muddy water coming out until the thermostat would close. I would turn off the hose and wait till the engine came back up to temperature. After just a few cycles it was running clear water. I was very impressed with that system. I have never had such a neglected system since then but I also have not seen the flush and fill kit offered in a long time. I would confirm that the sensor for the radiator fan is seeing the high coolant temps.
I think I still see those kits for sale at Walmart; though I would double check that chemical to see if it's safe for aluminum block engines. I've also used them, 30 years ago, when I was too poor to repair a small hole in my radiator. Used that aluma-seal stuff and flush it out a few hundred miles later. Those old cars had much larger coolant passages, when compared to today's cars..
Update: I’ve replaced the radiator with new one from duralast without testing for blockage or infrared temperature readings. I’ve had 30-40 mins drive mixed highway and city driving on power mode engine(after running on maint. mode for 45mins) didn’t go above 204F. It’s mostly around 195F. And low engine fan mode is also auto starting @200F. So I guess the culprit was the radiator. Thank you everyone for your inputs!! I’ll keep driving and monitor the temperature.
Probably this. Bar's Leaks HG-1 HEAD SEAL Blown Head Gasket Repair https://a.co/d/7Y1dxfR Posted via the PriusChat mobile app.
I've driven for past 2-3 weeks while coolant temp is below ~202F but somehow it doesn't have any pressure buildup if I open reservoir cap. I replaced the cap as well but still the same. The coolant level is at the full mark and not losing any coolant. Any air leak or an air pockets? The coolant lines still bypassed the heater core and heater core exchange
