P0304 Cylinder 4 Misfire - Headgasket Replacement

Exactly. At least it's not raining on me this weekend. Bolting on the heads in the rain was thrilling

 

Yuck.

 

Not sure if anyone has mentioned this, but bad head gaskets were a common issue on early 2nd gens. Toyota changed their head gasket design on the 4.0 in like 07-08ish

 

Some progress.

 

Nice and tidy! Becareful of those lower orings when reinstalling the cover. I like to place some silicone lubricant on them so they slide over the oil pan nicely.

I also recommend a little extra silicone on the crease from pan to the block. Some help installing the cover is a good idea due to the oil pump needing to be lined up.

I'd say good luck, but you are very meticulous and will have no issues.

 

Thank you for the helpful tips, I definitely review all recommendations before proceeding .

Man I hope you're right. I literally obsessed for hours preparing things, reading the instruction manual, and then to work as fast as possible with the sealant. I still fought the oil pump a bit even after several dry runs. I really have no way of knowing if the orings stayed put, I can't see them anywhere though so I guess that's good. I used a tiny bit of grease to help stick the orings in place. I put the sealant everywhere practically, wish I could've gotten a picture before I put the cover on but I was in a hurry!

 

Sorry for the plural, it's 1 oring from the oil pickup to the pump.

Looks good~!

 

I thought the other one you were referring to was the one closer to the top above the water pump. The one at the bottom definitely had me a lot more worried ( there's no way for me to be 100% that it's in place and didn't get smushed out, but I think I got it).
Disappointed I didn't finish today, but had to call it quits for the night:

 

Finally. I'm not gonna sugarcoat it, that was a pain in the ass. Moment of truth has arrived. Time to go start it and see if it explodes

 

I'm having a difficult time getting the oil pump to prime, dammit! I've got the spark plugs back out now and I'm cranking for 20 to 30 seconds and waiting a minute and then cranking for another 20 to 30 seconds so far nothing after five times. Argh. Suggestions?

 

Never mind, I finally got guts enough to put the spark plugs back in and start the engine. Oil light went off after a few seconds. Vrum vrum! Everything seems to be all good thus far.

 

So I suppose I can conclude the surgery was a success. I still got the P0430 Bank 2 emissions check engine light for the first 2 days after repair which had me worried, but I kept resetting the codes and monitoring the CEL tests with my reader, and yesterday noticed it cleared the tests, so I immediately went to the nearest smog station and about 20 mins later I passed the smog test. Just in time, my registration's up at the end of the month.

So far, no leaks, no funny noises, no issues. And there's something satisfying about seeing nearly crystal clear oil on the dipstick.

For anyone else who may come across this thread replacing a HG with a similar (minimal) mechanical skill set, here's a few things worth noting:

1) Pull the radiator. The extra space is a very good thing. There's still the air conditioning cooler in front of the radiator that you will need to take care around or protect.

2) When reassembling the drive belt, put the belt into place before assembling/mounting the fan/pulley onto the water pump. There was not enough space to slide the belt between the crankshaft pulley and the water pump's pulley after assembled, I had to learn the hard way.

3) Follow the suggestions others posted, like removing the studs near the oil pan, lining up the oil pump ahead of time, take care with the o-rings for the timing chain cover. I personally put sealant on somewhat heavy, applying it to basically all machined surfaces on the timing cover, then hitting the block with sealant at block to head joints, the 3-4 inside circular spots, and generously on the top of oil pan and inside connecting corner.

4) Study and follow your Haynes/chilton manual carefully. Label everything using sandwich bags and tape. I numbered each timing cover bolt on the picture in the manual and on the bolt itself, then used a black sharpie to mark the bolt number onto the cover itself to help speed up reassembly.

5) I cleaned my sealing surfaces with a ton of brakeclean, fine steel wool, my Dremel with an assortment of pads, and both non-scratch and regular scotch pads. I plugged my orfices to keep the debris out, swept with magnets to collect wool dust, and flushed and cleaned up thoroughly. I should note the crusted baked on goodness on the pistons practically fell off after a few days of sitting plugged with paper towels just due to the moisture in the air.

6) Get a master gasket set and replace all encountered.

7) I struggled to get the crank pulley bolt free, even wasted some money on a pulley holder that didn't work. Since mine's a manual, I put truck in 6th gear and yanked away with 5' worth of breaker and cheater bar. Felt bad yanking counter-clockwise with that much force, but it was the only way for me.

8) I struggled with disconnecting a lot of my coolant and oil hoses, ripped several in half actually trying to break the bond with pliers. Finally got a good technique going of cramming a small screwdriver between nipple and hose to break them free.

 

For 10 points, who can name this sensor:

I apparently broke the clip on this so I had to macgyver a zip-tie to secure it, although I may have pinched the hose a bit with the tie and it sits slightly differently with the tie than with the original clip, but I figure it should be okay... I have no idea what it is though, some sort of air tube sensor thing.

 

Glad it all worked out.

I always cut a piece of cardboard/plywood/sheetmetal/ styrofoam/etc and tape it to the condensor. It wont always stop a something like a screwdriver but it will help keep you from damaging it and adding to the cost of the repair.

 

Are you talking about the breather that has the black ziptie?

 

Great job on the repair, man! That mystery sensor looks like it is your front differential or transfer case breather. Just follow the hose to the other end to be sure. I'm not for sure on this, but I thought the breather worked better when installed pointing upwards.

 

Nice work man, without a garage to boot.

 

Yeah I kept thinking about putting up protection, but ended up just being careful around it. Only did very minor damage to the fins, but if I were to do this again I'd definitely get some styrofoam or similar.

Yes. So it's a breather, huh? Makes sense, I should've known.

Cool. I zip-tied it upwards, and it sounds like as long as I didn't pinch off airflow completely with the zip-tie I should be fine. Good.

Doing the repair outside during the winter months over a gravel driveway was not ideal. But its done. Thanks for this forum and everyone's pointers, very helpful. If I get enough energy to post final parts lists/costs, I will. But to approximate, all said and done, I was in to this about $2,700 + truck rental. Thats about $1,950 to the dealership for parts after returns, $125 to machine shop, and about $600 for coolant, oil, filter, rags, various cleaners, gloves, spark plugs, rags, tools, etc. Although I probably could've gotten a shop to do this repair for marginally more, I feel I did a more thorough job than a typical shop would have, plus I gained all new idlers, tensioners, belt, radiator, hoses, etc. that wouldn't have been otherwise included.

One final question: how many miles you think I should go until I change the oil again? my gut says maybe around 500 miles then change to get any residual crud out of the engine.