Cylinder 2 Misfire - Is It The Infamous Headgasket Failure?

As someone who just replaced the engine in my 2010 Prius with head gasket failure, I can attest to a few things.

1. I can almost guarantee this is a head gasket failure. You are lucky, mine failed at 100,000 miles. These will fail, just if a matter of when. To inspect, you can buy a liquid to test for exhaust gases in your coolant. If the liquid changes color with the coolant, you have a head leak. Don't go to a mechanic and waste hundreds of dollars like I did to do what amounts to 5 seconds of work.

2. The head gaskets fail without any regard to overheating or maintenance, it is a fault in the engineering of this car. The consensus is that the water pump gradually fails to produce enough coolant pressure or circulation and gradually starves the cylinders of coolant just enough to kill the head gaskets but not enough to cause an overheating. (In my opinion, planned obsolescence from toyota).

3. Replace the engine. When the head fails it can cause pressure in the cylinders and mess up your rods, cause the engine surface to warp, or the head to warp. You don't want to waste 20+ hrs labor just to swap the engine anyway. Swapping the engine vs doing the head gasket is almost identical on cost so why not get something rebuilt with some kind of warranty?

Make sure the engine that is swapped has updated heavier duty gaskets and also better head bolts. Even with those two replacements my mechanic still said they've seen premature failures on these engines without regard to the water pump or the intake manifold (although keeping these working with preventative maintenance can't hurt).

At the end of the day, the Gen3 Prius is a lemon and Toyota should have to pay up. It's ridiculous in this day and age to see head gasket failures of this magnitude.

SM-N960U ?

 

All very good questions. I have a blown head gasket on my 2014 and am awaiting parts from Toyota. In the mean time I will be disassembling, cleaning EGR and getting things ready.

I’m very curious as to the root cause of the head gasket failures. I had a 79 FJ40 that had well over 600,000 miles on it. I want Toyota reliability to come back and this head gasket issue is puzzling

 

1) At your mileage, there is a strong possibility. You mentioned that the coolant level was low, but without knowing where it was previously, there is no baseline to work off of. I would fill the coolant level to the full mark so that you can have a reference.
2) Keep a pressure tester connected to the reservoir overnight and recheck each cylinder for coolant in the morning.
3) If the engine is clean, does not consume a significant amount of oil, and the bottom-end is still good, then a headgasket repair is a viable option.
4) No one really knows - we all have our own theories. On mine, the headgasket itself had a broken seal and between 1 and 2 and one of the head bolts got a bit loose.
5) Usually the block is fine, but be very careful about what you use to clean the surface. I suggest sticking with plastic razor blades and CRC gasket remover. You can use a fine-grade wire brush sparingly if needed. OEM head gaskets need a surface finish of <30rA to seal.

 

congrats!

 

Great news, no more misfires.

As for cooler, save money and time with pressure washer. At our last meet up Raytheeagle cleaned 3 coolers in 15 minutes compared to the traditional half day soaking and rinsing.

 

Sometimes a half day is a good result .

It could take more than a day or longer.

But we’ll employ the solution that is much less than that and allows 2 circuits to be cleansed at a meet up.

Probably 2 more to do at the next meet up, so be ready.

 

I have this infamous problem after just doing the head gasket, I also had the 0261b code but didn’t know if it was caused by low coolant, so I did the head gasket and reset the codes, drove the car for about 30 miles in 40 degree weather (never overheated) and the p261b returned. Now ordered the water pump and thermostat.

is it possible the 30 mile drive took out the head gasket