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Update folks, decided to hit the hardware store while waiting for the exhaust guy to come past and I grabbed bolt and a nut to make into a stud in case it could be welded. Decided to check to see if it'll fit into the hole and long behold it screwed into the block and caught the threads with no issue at all. Sooo now I have 2 good holes (thread locker will be used for sure) and I have to grab a shorter bolt because the one I grabbed was to long. Now to figure out the top left bolt 🤔
I would change the head if it was my car. The factory service manual will be your friend on a job like this. The exhaust Y pipe has to come off, the driver catalytics, driver exhaust manifold, balancer, timing cover, timing chains, driver valve cover, upper and lower intake, rear head coolant tube, and then the head can be removed. The service manual will have the timing chain alignment procedure which will be the scariest part of it all. It will also have the head bolt torque procedure. You will need a new head gasket, some say head bolts but I have reused head bolts so many times with zero problems that I wouldn't buy new unless you just want them. It would be best to have help from someone that has changed a head on a OHV type engine if it's your first time. Or plan on taking a lot of time reading up and doing it slow.
I know engines are only $700 - $1200 with low miles but it's probably more work and time to swap it out. With the head, gaskets, rtv, ect ect you'll probably be in it $300 or less.
It's definitely a daunting task, but like scumbagsleeper said, it'll likely be significantly easier and cheaper than an engine swap. You'll end up with a better understanding of how your engine works and a good knowledge bank for the future. I rebuilt a straight 4 back in high school, took the whole summer to do it, had a few hicups, but all in all, I knew that engine (and engines in general) much better than before, and it was very satisfying having her fire up the first time.
Honestly I really feel like the swap would be easier if it's setup closely to my previous g35 (which it looks like) I've done a 2 swaps since my first and I pretty much can do it in a few hrs through the front. Not saying this is what I prefer but the unknown is always a bit scary lol
I want to thank everyone for chiming in and trying to help. Hopefully this issue can come to a resolution this weekend. Hopefully lol.
OK welding was a no go, no one felt comfortable doing the work and I understand that. So I decided to take a leap of faith and do it another way.
So out of the three holes on the block for the thermostat I only had one usable hole which was the top right.
Bottom hole was enlarged so the original bolts didn't fit. I
got lucky while at the hardware store grabbing some bolts to make a stud using jb weld and apparently one of the bolts I grabbed was longer and it actually threaded in.
So now we have 1 hole left and it was very bad so I took a leap of faith and cleaned it up sanded and cleaned it again then applied some jb weld epoxy and let it sit for 48 hrs.
Then I proceded to drill a small hole in the jb weld and gradually went up in drill bit sizes until I could fit a bolt inside and this is what I have now after sanding it smooth to make it flush
So after making some adjustments and getting some washers for the bottom bolt (it was a tad bit to long) here's where I am
The top left bolt is going to be converted to a stud and a liquid jb weld will be applied to the stud before inserting it into the hole. I've thought about threading the hole with a tap or even the bolt itself and using red thread locker but I don't know if that'll be sufficient enough.
I've really been taking my time mainly because life is so busy so I never really get time to myself but I have to say this seems like it'll hold with no problem after some black rtv is applied as extra insurance.
Hopefully I can be done on Thursday after I finish up conducting interviews for new hires at work. ☺
Honestly I'll just plug the hole like it was before. I grabbed a Shorter bolt to take the place of the long bolt that was there before. Drove it like that for 5 months and so no ill effects so I'm hoping that stays the same. I'm hoping it seals as well, I have the oem gasket that came with the thermostat and some rtv black so I'm praying for no leaks lol
Ultra black RTV will be the strongest sealant you can use for the gasket surface. I used Ultra black on my oil pan set once instead of grey and I had to pull them off later that year.... I had to use a mini sledge to break the casings apart I'm guessing that hole on the inside is standard threads and not a sealing NPT thread. If I was going to seal that hole up I would use marine weld and the bolt for sealing. It will be permanent. I fixed a water jacket that way before and never had it leak again. I guess at this point trying anything won't hurt since the outcome will be the same if it doesn't. (replacement engine or head)
Yeah I have some of the original jb weld instead of the steel stick I used for the bolt hole. I'll just put some on the threads and screw it in and let it sit for 24 hrs before applying the rtv. Marine weld would be better to use since it's going to be submerged in coolant right? Hence the name marine lol
And thanks for all the help so far man I appreciate it
Last edited by eazdaskeez; 09-16-2019 at 07:26 PM.
Marine weld is very thin metal epoxy and seals very well and is also water,oil, and chemical proof. I found JB weld is lot more porous and harder to make a seal. JB weld is harder and more machinable - better for drilling and tapping.
Now that we are talking about uses of JB weld, here is a instance you shouldn't use it for. We just bought a 08' G35x for my brother this weekend and the AC didn't work even though the guy had receipts of over $1k in work done to the system this summer. We found that they couldn't figure out where the leak was so they packed JB weld into the condenser service quick disconnects.... Well the real problem was the condenser o rings were sheared when they installed the lines wrong... fifty cents in o rings and a r134a recharge fixed it.
Thermostat mounted and rtv is on, hole has been filled. Go time is in the morning. Waiting for the rtv to cure and had to head to work. Everything torqued down nicely so I'm hoping for no issues
09-11-2019, 12:03 PM
I'm guessing that hole on the inside is standard threads and not a sealing NPT thread. If I was going to seal that hole up I would use marine weld and the bolt for sealing. It will be permanent. I fixed a water jacket that way before and never had it leak again. I guess at this point trying anything won't hurt since the outcome will be the same if it doesn't. (replacement engine or head) 
