HG questions. Background first: Long time Prius owner (14 years, 2010 w/~255k miles, most miles were from 80mi/day commute at 72-82MPH, now retired), long time lurker, rare poster. I'm in the middle of a head gasket job, my first after 255k. Uses 0.5-1qt per 10k oil change, Mobil 1 0w20. Besides DIY suspension work, rear hubs, and upstream O2 sensor, the car has been rock solid. I've not even changed plugs in 255k. Just religious 10k oil changes and several sets of tires. Issue started years ago, maybe once a month would have the shake at start up, gone in 2-3 seconds. Never paid no mind to it, as it was rare and didn't last long (I wasn't aware of clogged EGR valve and HG issues.) Then one day 2 months ago, it decided to start shaking all the time while my daughter was out with the car (it's her daily driver now). We had it towed home. I'm fairly handy with a wrench and YouTube videos, so I thought I would tackle whatever it is when I got home 2 months later. Well, I'm home. First thing I did was remove the plugs and check the cylinders for coolant on top of the pistons. None seen. Coolant in the tank has gone down, below the low, but not empty. All pistons looked roughly the same amount of carbon, nothing obviously washed. Put the plugs back in and decided to start it up and have a listen for myself. Engine started, and the shake didn't start until several seconds later. Shut it off. I saw a couple videos where they diagnose EGR Valve vs. HG by inserting a blocking plate/putty knife between the EGRV and tube. I did that, started, and zero issues. Decided to take it for a short half-mile drive...no issue. Came back home, shut it off, started it again a few minutes later, and about 15 seconds after the engine was running, the shake started. Shut off. Repeated test, same thing, shake about 10-20 seconds later. Got out the OBD2 and had 3 pending faults in Torque Pro: P0300, P0301, P0302. Oh, never had a check engine light ever (in the last many months, not since I had an upstream O2 fail). Swapped coil packs 1 & 2 with 3 & 4 just to make sure that wasn't it. Fired up car and OBD2, same pending faults. So, I'm thinking not EGR related, and head gasket related. After arming myself with lots of YT video knowledge in the order of removal, I finally just got my head off. I'm not a pro, but this head gasket doesn't seem to have an obvious blow out like I've seen in YT videos. First question, how does this gasket look to you? Still on block, and piston tops: Top: Bottom: EGR Valve had some carbon on it, but wasn't really caked up. EGR tube to intake wasn't bad either. Intake manifold EGR ports were not fully clogged (maybe 50%?). But the EGR Cooler appears to be 100% clogged, brake cleaner wouldn't drain a drop. (And again, never any check engine codes.) It's taken 2 days of oven cleaner and pressure washer to get a few of the passages passing light. Could this have been my problem and not the head gasket? I have Fel-Pro gasket set, new head bolts, water pump, thermostat, and finally some spark plugs. Is having the head checked and machined required/highly recommended? Besides flatness check and machining for that, what else is typically done/recommended?
2z not good candidate . Mileage is wer gen3 are buried generally . But you can play all ya like .you've time now. But daughter may need to get to work reliabley. Gen2 if you can believe . Or electrify her or another gasser . From one old retired military guy in the business don't do it .. piddle around play with all ya like . Don't depend on it . 2010 is when Toyota became like all the rest look all from 10 forward . Race to bottom buddy .
I don’t see any obvious failure on head gasket either, though there is general “erosion” of the black zones around coolant passage holes. cylinder one piston looks somewhat cleaner, say compared to four. Maybe coolant incursion into cylinder just starting. the FelPro gasket kit is apparently one custom head gasket, and an incomplete assortment of “this’ll do” smaller gaskets. The Toyota “overhaul” gasket kit is much better option.
