opened up a 254K mile prius. plus some mods

hello all ,

New guy here. My wife bought a 09 with a blown head gasket. I was not very excited about the job ahead but was very excited to get into a vehicle with high potential for MPG.

Did not know much history on the car but I will give you a rundown. Blown headgasket and would not hold its water. Idled very smooth had ok power. Everything else was in good shape. New traction battery.

After a test drive to confirm engine was not a waste of time I tore into it.

The head did not require any head work. Valves all were in specs. The Buckets were needing larger size. I measured them all only Cylinder 1 was withing spec. I absolutely did not want to go through and get buckets for this car. So I put the old ones back in. No sludge, just varnish. Lots of carbon. Spark plugs were cleaned and reinstalled. Not sure if they were original or not.

Pistons (not pulled) had carbon all over them. Cleaned them up. Piston walls had very slight traces of original honing. I soaked the piston with seafoam for a couple of days. Cleaned them up nicely.

Oil pump was within specs and did not need to be replaced.

I replaced the chain and exhaust sprocket and chain guides with chain tensioner. Guides were technically in spec too. Chain was still in spec. Wanted to change the VVT but was lazy. VVT Actuator was still functioning good and kept it. (No CEL or code for it)

I looked at the intake for possible porting. There not bad at all for this car. I felt no need to clean or gasket match anything. I just cleaned the intake.

Exhaust header was untouched. I simply wrapped it with header wrap to hold the heat in better.

I also wrapped some hoses to help hold the heat in the car. The hose to the heater core, thermos and back. The heater core loop. I wrapped the thermos cause I had extra wrap.

I removed the resonator from the intake and removed the (screen?) in the filter box cover.. That gave some pep to the car. Focusing more on efficiency.

The Post cat was sent to the big "litter box" in the sky. Again focusing on efficiency.

I was encouraged to see how well all the parts have gently wore down. With that many miles I was dreading the idea of finding so many things to replace. I dont believe the engine was opened up. But I can tell clearly the CVT was rebuilt or remanned.

I just took her out for a drive today and its running very good. once the computer gets everything figured out I will see where the MPG sits. Not sure how long it will take to relearn everything.

I wanted to post this to help give and receive information.

Hope everyone is having a good day. =0)


CJ