I have a 2013 G37x Sedan at 54k miles. However, the car was manufactured in September 2012 so planning to replace the coolant with OEM Nissan Blue since it is at the 7 year recommend mark. I am seeing many posts about coolant leaks with this car which is making me nervous. For a piece of mind, I want to replace the hoses and clamps.

I consider my self a noob but feel comfortable with this project. I do have some possibly dumb questions:

1. Hoses, where would be a good place to order them in the US? I heard about Z1 Silicone stuff being good from a friend but does that apply to coolant hoses or just intake? What exact coolant related hoses would I need to replace and which and quantity of clamps? Edit: After some research, it appears I just need the following hoses: https://www.z1motorsports.com/z1-pro...et-p-3716.html & https://www.z1motorsports.com/coolin...e-p-12050.html & https://www.z1motorsports.com/z1-sil...et-p-5202.html I am hoping the rear hoses behind motor by the firewall, the hoses can be replaced although tight fit?
2. Should I replace the thermostat? If so, does anyone know the brand of the OEM thermostat? I wonder if I can get that from Rockauto for cheaper.
3. Should I get an OEM radiator cap or can I just get one from Rockauto?
4. Does any one have the part number for the o-ring for the drain plug gasket and bleeder valves? I assume I would need 3 of these from the following video:

From the following DIY video:


Thank You!

 

Definitely replace the stock plastic heater core hose with the z1 unit.

 

Thanks! I am debating if I should do this all in the Spring, or think it is essential to do now since car is now 7 years old? Starting to get chilly outside and I won't be able to do it until next week or two.

 

I think if it's not leaking you can do later. But no guarantee it wont break this winter.

 

I wonder if more issues of pipes cracking in Summer with heat. Hmmmm. Anyone else have any advice/feedback? Thanks!

 

Do I need 2 or 3 gallons of coolant if I am replacing hoses? I heard it's 2 gallons but another DIY suggested 3 gallons for our car.

 

I used about 1.5gals when doing a drain/fill. I think 2 gals should be plenty. So long as you don't open the seal, it should be returnable.

 

Thanks for the help everyone. I made a list on what to order with links to make it easier as it took me HOURS searching numerous threads on what exactly I need when doing a coolant flush. I compared prices with local dealers, eBay and other online Nissan/Infiniti vendors. The combo below was cheapest. I ordered the thermostat and gasket from eBay since I had some coupons and eBay bucks which made it cheaper. Surprisingly, cheaper to buy coolant with Z1 since shipping increased just by ~$4, saved few dollars compared to the $20.99 local Nissan dealer prices. Hopefully I am not missing anything else.

Z1 Motorsports:
Z1 Silicone Heater Hose Set - Link
Z1 Metal Coolant Bleeder Port for Heater Hose + Spring Clamps - Link
OEM Radiator Cap - 21430-8999C - Link
OEM Thermostat - 21200-31U03 - Link
OEM Thermostat Gasket - 13050-31U00 - Link
6x OEM Heater Hose Clamps (Need only 6, since cheaper to get the other 2 when adding on with the Bleeder Port package as need a total of 8 clamps per the diagram) - 01558-00521 - Link
2x OEM Nissan Blue Coolant - Link

Concept Z:
4x OEM Upper and Lower Radiator Hose Clamps - 01558-00731 - Link

Amazon:
Lisle Coolant Funnel -
Also, if one on a budget they could also just get the Dorman 56438 metallic heater hose connector instead of the Z1 bleeder one as suggested in another thread.

 

I ended up doing this job the other month, luckily it was on a nice enough day. I did it at a friend that has hundreds of tools, I am very thankful I did this. The job took about 3-4 hours but I was taking my time. The hardest part was removing the rear hose on the passenger side where the plastic piece connects the two hoses. In the end, had to cut it it and even then it was hard to remove so it required 4 hands at the same time pulling in opposite directions to finally get it loose. I did not bother replacing the hose that connects to the back of the motor to the plastic piece. I tried various tools including the clamp that is like a wire but unable to loosen it but no luck. Same thing for the hose at the firewall behind the driver side. The spacing behind there was even tighter, I gave up after 5 minutes as I knew it would be too tough to do especially with it starting to get dark.

I am hoping I won't have issues with those hoses, but will keep the spare Silicone ones just in case. Anyone out there that was able to remove those hoses with ease? The other hard part was to close the brand-new 01558-00521 clamps. That took way too long especially in the odd angles by the firewall. This was the toughest job I have ever done on my car, but due to the tight space and weird angles. I had to use WD-40 to slide the new OEM clamps over the front Gates hoses too. At least I have peace of mind for several more years now.

 

I used worm clamps when I replaced the OEM heater hose coupler. The stock clamps are a pity to work with in tight spaces.

 

I use to do my own rad fluid but dealer charges 80 bucks