Head Gasket Failure

25K miles ago, the P0300, 01, and 02 codes indicated EGR clogging which was thoroughly cleaned, along with intake manifold cleaning and input damper plate was replaced. Everything was going well, until I hit a block of ice causing gradual oil starvation. I got my passengers to the airport (probably ten miles). Although the oil light was on for about 5 of the 10 miles, the light went off briefly when parking, showing there was at least something left on shutdown. Adding new oil and liquid head gasket fix, the car ran great and mileage went from the 42 mpg of the past 25K miles to 48 mpg for the last 500 miles.

I thought of myself as a genius...for awhile. Then the coolant started disappearing with at least one episode reaching 240 degrees coolant temp. Also, there was excessive crankcase pressure, although I'm thinking this may have been going on previously. Whether the liquid gasket repair failed because I didn't follow instructions I have no idea. I've read that some people have had long term success with such products but the Gen 3 Prius seems to have a real vulnerability between Cylinder 1 and Cylinder 2 with combustion gasses bypassing into coolant or into the adjacent cylinder.

Anyway, the engine block and head seem flat and there is still some cross hatching visible so I'm putting things back together with new gasket and bolts. I know a new motor or even JDM is probably a better long term play but don't want to part with $2K or $6K or whatever the current numbers are.

 

The head gasket is bowed about half an inch although the block deck and cylinder head are flat. There's a clear defect between Cylinder 1 and Cylinder 2 on both the upper and lower surface.

 

I think you're right that the head gasket might have been compromised by the earlier EGR problem. I think I remember doing a leak down test when the damper plate failed but not sure on that and wondering whether that would've shown the problem. Combustion gas bypass between 1 and 2 might have caused the 42 mpg which spiked to 48 mpg with the short lived liquid gasket fix? Basically the problem would have been present for 25K miles with no codes or symptoms except maybe excessive crankcase pressure.

 

I'd probably do a JDM or junkyard motor (maybe $2K or $350 respectively) if the head gasket replacement doesn't do the trick. I basically will have $300 in parts and 40 hours of time that I usually spend watching TV otherwise. I'm going to thoroughly flush the cooling system which I'm hoping will get any foreign matter out.

 

Interesting. Yeah, I've been seeing the JDM motors with around 40K for 2000 or so. reman if good quality would probably be superior. Would consider that. This 2013 is probably gonna need some HV battery help as well as it's in the 60 percent range and I think at 230K miles it's the original OEM item.

 

I have a 2007 and 2013