2001 Monte Carlo 3.4 LS

I was wondering if anyone here may know what type of screw it is so that I can buy a replacement.

I can't seem to find where I placed the bottom screw to close it back up. I have the top screw in but I am missing the other.

I have looked all around for it but I just can't seem to find it.

Also is it safe to drive the vehicle without that 1 screw. I have the top one in tight and I placed sealant around the house for a good seal.

On head piece of the top screw says 98 but i noticed a lot of other screws in my vehicle have that number to.

 

It sounds simple, but you might be able to take the one you have and go to Lowe's or Home Depot and replace it. Might go to an auto part store as well. I would say no, it's not safe to drive around like that. The cooling system is under a lot of pressure and would blow through the housing for release, possibly breaking it.

Other place to check, junk yard.

 

The 98 (9.8) on the head of your metric screw is the grade classification indicating it is made from either low or medium carbon steel and tempered. As suggested, a replacement screw can be obtained at a wrecking yard or hardware store using the one you have as a sample to match the diameter, thread pitch and length you need. I would not recommend driving the car with the lower bolt missing.

 

You definitely want BOTH of those bolts. It would not take much pressure in the cooling system to spring a leak. Your BEST bet is:
- Dealer (but you will PAY for it)
- Take the other bolt to a hardware store and match it up
- Junk yard (get OEM quality at non-OEM price)

 

thank you all for the responses. I took the bolt down to Lowes and found a good match. After I went to Chevy Dealer next door and it was 88cents for one but they didn't have any in stock and I would have had to wait 5days.

So now my thermostat house is tightly secure.

I have another question but not sure If I should make a new thread on it so I'll post it here.


I put in coolant through radiator and took off the bleed screw. Put everything back on and ran the engine for 10m with heater on blast.

I then drove the vehicle just a bit and when i got home, where the coolant reservoir is it was smoking a bit. The smoke was not black it was kinda white like steam but It didn't look like it was coming out with pressure so im unsure of what it could be.

2001 Monte Carlo 3.4L It's night so tomorrow I'll post a pic of where im talking about. I can't really describe the smell however it smelled kinda like coolant but I didn't splash any in that area when I put some in the reservoir.