I'm an idiot - thermostat bolt

CamaroChriSS · 10-23-2025, 09:46 AM

Replaced my thermostat (had the issue of the temp dropping to zero and fans coming on full blast) and stupidly snapped the head off one of the bolts. Thankfully was able to thread it back out with pliers, but now I need a replacement. I'd really like to be able to use my car today, so I don't want to wait for something to be delivered - is this a bolt I can get a hardware store, or is there anything special about it? Looks the end end is a little tapered, and is there some sort of heat rating it needs?

Stupid situation, stupid questions, I know - need help!

Vtor_ZL1 · 10-23-2025, 09:48 AM

in pinch, same thread pitch / length from hardware store may be enough until you can source proper OE corrosion resistant bolt.

CamaroChriSS · 10-23-2025, 09:50 AM

Quote:

Originally Posted by Vtor_ZL1

in pinch, same thread pitch / length from hardware store may be enough until you can source proper OE corrosion resistant bolt.

thanks - I hadn't even thought about it being corrosion resistant. I'll order one now and see if I can get the same size locally.

Anyone know the specs on the sizes of these?

ctrlz · 10-23-2025, 12:32 PM

Why don't you just use stainless? Stainless are sold as thermostat bolt "upgrade" kits. The fastener boxes in your local hardware store should have a decent variety.

piening2150 · 10-23-2025, 01:24 PM

Quote:

Originally Posted by CamaroChriSS

thanks - I hadn't even thought about it being corrosion resistant. I'll order one now and see if I can get the same size locally.

Anyone know the specs on the sizes of these?

Take the bolt you didn't break with you to the hardware store and match it up. Most stores will have a thread gauge mounted nearby to help you figure it out.

speedyink1 · 10-23-2025, 01:33 PM

Even if they don't have one of those thread gauges just go to the selection of nuts and trying spinning them on the bolt to help determine the proper thread

CamaroChriSS · 10-23-2025, 04:01 PM

Thanks all! Took your advice, grabbed one of the non-broken ones, used their thread sizer, and got (a couple) stainless replacements - all buttoned up now. Thank you!

*Joshinator99* · 10-23-2025, 10:46 PM

FYI they’re M6x25 Hex Head Flange Bolts. I’m using titanium versions for my billet thermostat housing.

bishopts · 10-24-2025, 08:34 AM

Quote:

Originally Posted by Joshinator99

FYI they’re M6x25 Hex Head Flange Bolts. I’m using titanium versions for my billet thermostat housing.

M6x1.0x25
M6=bolt diameter
1.0=thread pitch
25=25mm long

2018 Blue 1LE · 10-25-2025, 11:34 AM

I know OP got it figured out, but found this with a quick search just for FYI to someone in the future:

https://www.autozone.com/nuts-bolts-...ece/848417_0_0

https://www.homedepot.com/p/Everbilt...e-more-details

Material is listed as steel, but it is in a auto parts store so it should be the correct bolt.

Home Depot is listed as zinc plated.

Either should work in a pinch.

bishopts · 10-25-2025, 01:34 PM

Its a pretty common bolt. No matter what your neighbor drives you can find one on their car.

ctrlz · 10-27-2025, 01:32 PM

Quote:

Originally Posted by 2018 Blue 1LE

Home Depot is listed as zinc plated.

Zinc plated I would use on the hinge for my backyard gate.

Thermostats on our cars seem to be an eventual maintenance item. I would use stainless, and probably anti-seize as well. No fun removing a corroded thermostat bolt (or any corroded bolt).

2018 Blue 1LE · 10-27-2025, 09:12 PM

Quote:

Originally Posted by ctrlz

Zinc plated I would use on the hinge for my backyard gate.

Thermostats on our cars seem to be an eventual maintenance item. I would use stainless, and probably anti-seize as well. No fun removing a corroded thermostat bolt (or any corroded bolt).

Agree, just throwing out options in a pinch.

NZuercher · 12-05-2025, 12:56 PM

Quote:

Originally Posted by CamaroChriSS

Replaced my thermostat (had the issue of the temp dropping to zero and fans coming on full blast) and stupidly snapped the head off one of the bolts. Thankfully was able to thread it back out with pliers, but now I need a replacement. I'd really like to be able to use my car today, so I don't want to wait for something to be delivered - is this a bolt I can get a hardware store, or is there anything special about it? Looks the end end is a little tapered, and is there some sort of heat rating it needs?

Stupid situation, stupid questions, I know - need help!

Did you replace the thermostat only, or, did you also replace the temperature sensor? If you only did the thermostat, did that fix your issue?

10-23-2025, 09:46 AM	#1
CamaroChriSS Drives: 16 1SS M6 Black -previous 00 Z28 M6 Join Date: Oct 2018 Location: DC Posts: 261	I'm an idiot - thermostat bolt Replaced my thermostat (had the issue of the temp dropping to zero and fans coming on full blast) and stupidly snapped the head off one of the bolts. Thankfully was able to thread it back out with pliers, but now I need a replacement. I'd really like to be able to use my car today, so I don't want to wait for something to be delivered - is this a bolt I can get a hardware store, or is there anything special about it? Looks the end end is a little tapered, and is there some sort of heat rating it needs? Stupid situation, stupid questions, I know - need help!

10-23-2025, 09:48 AM	#2
Vtor_ZL1 Who Needs to KNOW? Drives: 18 ZLE Join Date: May 2018 Location: Left Side of the Moon Posts: 1,839	in pinch, same thread pitch / length from hardware store may be enough until you can source proper OE corrosion resistant bolt. __________________ ing for grip. Are you in the NY/NJ/PA/CT region? Join us for autox fun at MetLife Stadium. HUGE lots, tons of runs. http://www.motorsportsne.com/

10-23-2025, 10:46 PM	#8
Joshinator99 Moderator Drives: 2017 Camaro 2SS A8 Join Date: Aug 2018 Location: Petersham MA Posts: 6,192	FYI they’re M6x25 Hex Head Flange Bolts. I’m using titanium versions for my billet thermostat housing. __________________ 2017 Chevy Camaro 2SS A8 Whipple 3.0, Mast Black Label heads, ATI 8L90, Fore triple in-tank pumps, 112mm TB, LPE +52% injectors & BB HPFP, TooHighPSI/Katech port injection, 15” conversion 1066 WHP STD/1027 SAE, 9.10@152.5 (new times coming)

10-23-2025, 12:32 PM	#4
ctrlz Drives: 2017 2SS, 50th pkg, M6, MRC, NPP Join Date: Jan 2016 Location: Ocean City, NJ Posts: 3,555	Why don't you just use stainless? Stainless are sold as thermostat bolt "upgrade" kits. The fastener boxes in your local hardware store should have a decent variety.

10-23-2025, 01:33 PM	#6
speedyink1 Drives: 2023 Camaro 1SS 1LE 6MT Join Date: Nov 2023 Location: Vancouver Island Posts: 552	Even if they don't have one of those thread gauges just go to the selection of nuts and trying spinning them on the bolt to help determine the proper thread

10-23-2025, 04:01 PM	#7
CamaroChriSS Drives: 16 1SS M6 Black -previous 00 Z28 M6 Join Date: Oct 2018 Location: DC Posts: 261	Thanks all! Took your advice, grabbed one of the non-broken ones, used their thread sizer, and got (a couple) stainless replacements - all buttoned up now. Thank you!

10-25-2025, 11:34 AM	#10
2018 Blue 1LE Drives: 2018 Hyper Blue Metallic 2SS 1LE 6M Join Date: Nov 2024 Location: here Posts: 194	I know OP got it figured out, but found this with a quick search just for FYI to someone in the future: https://www.autozone.com/nuts-bolts-...ece/848417_0_0 https://www.homedepot.com/p/Everbilt...e-more-details Material is listed as steel, but it is in a auto parts store so it should be the correct bolt. Home Depot is listed as zinc plated. Either should work in a pinch.

10-25-2025, 01:34 PM	#11
bishopts Drives: 2017 2ss 6mt Join Date: Mar 2024 Location: dallas Posts: 941	Its a pretty common bolt. No matter what your neighbor drives you can find one on their car.

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