Seems the Prius is known to blow head gaskets, reason being attributed to the hybrid system, the engine switches off and on so often, heating up and cooling down all the time.
I am using the official TIS repair manuals. I am warning you, this is a lengthy job, it is not something you can finish in a day.
Tools
There are plenty of tools that you will need along the way, everything from the tools needed to take out the EGR, to a triple square bit to remove the cylinder head bolts, in any case, here is a list of tools i recall needing
- A ratchet, breaker bar, and a cheater bar
- A torque wrench (I use ACDelco’s ARM302-4s)
- Oil filter removal tool
- 10mm bi-hexagon wrench (An M12 (12mm triple square) bit will do if you fail to obtain the bi-hexagon ! but you will feel a bit of wiggle in it)
- A pair of pliers
- 12mm socket (Many screws)
- 14mm socket (Many screws)
- 19mm socket (The harmonizer / crank pulley)
- Feeler gauges down to 0.004 (0.004 is the maximum acceptable engine warp)
- A super straight bar to assess the engine against (Laser cut)
- Harmonic Damper removal tool such as Schley 64300 (I made my own simple tool that works)
- A tool to take out the valve stem seals (I made my own)
- Patience
The Harmonic Damper removal tool
There are many ways to remove the pulley (Harmonic Damper), 1- the most common of which is using a torque impact drill, it just works, but my gut feeling tells me it might not be wise, if it was, Toyota would have approved it, 2- another popular way is to use a belt or strap and tie it to a strong part of the vehicle and around the pulley to use friction to hold the pulley in place, problem with this method is that if it is not 100% horizontally aligned, and the pulley is being pulled in or out, it might cause damage, 3- and there is the Toyota way, which is based on using a tool to hold the pulley in place while you loosen the screw, examples of such a tool is the Schley Products 64300, I don’t have access to such a tool, so I improvised a tool that holds the pulley against the engine mount
Parts
Distilled water
7 Liters of distilled water, You are probably going to need to use distilled water before engine coolant to flush the engine from the contaminated coolant in the car, it was contaminated because your head gasket broke, and exhaust went through that coolant.
Engine Coolant
(Applies to both Fix and repair)
If the coolant has been contaminated with engine exhaust, you will need to flush and add distilled water, then after a day (a day of light use, and zero days of the car sitting), remove as much of the water as you can and add the SLLC coolant (Do not run on distilled water for more than 1 day).
Totota’s coolant is super expensive, if you are looking for something other than the OEM, or want to understand the risks and advantages, check out my Toyota’s coolants post
The car takes 6.5 liters of coolant, every container is 2 liters !
Oil and oil filter
(Applies to both Fix and repair)
if the engine oil has been contaminated (And it has), you will need a new filter and new oils
Expected cost (35JD)
Gasket kit
PN: 04111-37316
The repair manual states that you will need a new gasket kit, the gasket kit has the following parts.
FIPG 103
PN: 00295-00103
The form in place gaskets from Toyota are best, but they are very pricey, I went with an aftermarket German brand (Victor Reinz Reinzosil) that is high quality (Used by German brands as OEM !) and have my fingers crossed, the Toyota FIPG costs around $50, the Victor Reinz Reinzosil (Universal) aftermarket brand costs less than 6 dollars
Cylinder head bolts
(90910‑02164 and later was superseded by 90910‑A2009)
Those are Torque to yield bolts, when you install them, they are stretched, and should not be used again, In my case unfortunately, Al markazeyah Toyota does not provide them, I was told today that they did have them at one point, and they cost $5 each (10 of them is $50), but they no longer carry them ! yes, I know, what the duck, as an exclusive dealer in Jordan, they absolutely should have them.
The Toyota repair manual often tells you to measure the bolts after removal, and replace them if they are out of spec — a classic sign of TTY design, even if not spelled out.
The process
Removing the spark plugs
Getting started with a big surprise !
I started by removing the spark plugs, like you normally would, and to my surprise, those brand new spark plugs (Less than 5000 KMs) are broken, and the ones that were broken are not even the ones where the head gasket leaked into ! Here is more about the failing spark plugs