I read the previous posts about the radiator problems here. I have an experience to share, and hopefully get a little guidance. My 2010 EX35 radiator sprung a leak this past summer at a little over 90K miles. Sounds like the same side as the others, too, passenger. I was on a trip at the time and it was at night, so I had to go to an unfamiliar shop to get it fixed the next morning. I think the radiator part was fairly straight forward, but they mentioned it would be a good idea to replace hoses and thermostat at the same time. Sounded reasonable to me, but it has been a nightmare ever since. They screwed something up either removing or remounting the new thermostat and it has leaked since then. I have pics of the screws and bolts they used to effect the repair if anyone is interested... I got tired of the leaking and refilling the reservoir and decided to take it to a local shop a couple weeks ago to get it repaired. About $600 later and much trial and error by this shop and it's still leaking. As info, it was ok for about 1 day. This local shop tells me there are three bolts that hold the tstat to the head. And, that if his first attempts to repair didn't work, the head can be removed and the holes filled and redrilled and retapped so the tstat can be properly attached. So, 1. are there in fact three bolts, 2. is the tstat mounted to the head (and not the block?), and 3. would his suggested repair be valid? I'm thinking I'll need to go to Infinity for this eventually. Anyway, any advice or help understanding this would be appreciated.
Thanks,
Dave.

Sorry to hear about your leak. One of the wonderful things about this forum is the inclusion of the factory service manuals. They have saved me a few times!
Click here and go to page 20 for the thermostat....andh good luck! Hope this helps.
https://www.nicoclub.com/FSM/EX/2010/CO.pdf

Dave,

Sorry to hear about your troubles.

Looking at the cooling section of the factory service manual linked by XIS, it looks like your mechanic is right about the mounting and location of the thermostat. I'm not sure what fixes your local shop had attempted. But if they took the trial and error approach, and also couldn't fix it after a few tries, I'd start to question my trust in them.

The repair sounds valid to me. Most of the cost here looks to be tied to the labor. If you go to Infiniti, I think it's likely that the dealership will just go ahead and replace the entire head. That seems like it would cost a lot more. For me, what makes the decision tough is the projected cost vs. peace of mind. If you have a strong feeling that you'll eventually end up at Infiniti, maybe you should skip the local guy altogether.

I don't know what your situation is in regards to availability of transportation. I once had a costly repair on my EX that required a couple of days of downtime for the car. In my case, the dealership cost was almost the same as the local mechanic, but the dealer was able to get me a loaner for the days my car was out of commission. If I had gone to the mechanic, I would've had to get a rental car, which is obviously off-site. Now if you have an extra car around, or primarily rely on mass transit, this may not be an issue.

I know your situation must be frustrating, and I wish you good luck. I'd also be interested in hearing about what route you end up taking.

i don't mean to hijack your thread, but i'd be curious to find out if i have a similar defect as others. i recently acquired a 2012 ex35 with <50kmiles. i noticed the temperature is not as cool as the same setpoints as my G35. i thought i might have been low on AC fluid but i wasn't. perhaps this is a thermostat issue too?

Thanks for the info and the service manual section. It makes me feel a little better about a simpler fix than a new head. I did take the car back to the local guy,since he said it was fixed, who worked on it again saying the leak was at the head of one of the bolts, but that the threads seemed to be holding since he applied some kind of material he referred to as perma thread?? Something he had done years ago for someone else and found some on Amazon. Not sure what that is. He thought he might be able to find a soft metal washer-type piece that might compress and stop the leak, but he was unsuccessful in finding what he wanted. He said he had another idea, but I was in a time crunch and, after working on it a bit more, he had it back together and said he would need to drain the system to try to make some kind of permanent-type sealing repair on that bolt. After that, it is removing the head and going that route. It has actually been ok for several days, but now there is some decrease in the fluid level in the reservoir. I think I may be done with "maybe" repairs and might have to get over to Infiniti. I don't have any desperate needs for the vehicle the next two weeks, as, I drive a school bus and we are off for Christmas/New Year's Break. I hate the thought of paying a lot for the fix, but as you mentioned, it's peace of mind. And, I like the car.