Hello
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Joined: 03-15-14
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From: California
Hello
Hi everyone,
I got on here looking for an OBDII drive cycle to get ready for smog but also wanted to post a tip on overheating I came up with. I have a 2006 Cobalt with the 2.2 liter engine and after some engine work the mechanic could not get it to run under about 250 degrees. He put in 3 thermostats, finally including a chevy unit from the dealer, followed the bleed procedure, and still too hot. I finally had him just leave the thermostat out which made the car run around 150 and a trouble code for not up to thermostat temperature. That was fine until time to smog it. The solution I came up with may seem kind of extreme but I just drilled a few little 1/8" holes in the thermostat diaphram. I think that does two things, first it makes the system way easier to fill. Just take off the top hose at the engine and fill it up until coolant comes out at the top of the engine. Second, the piston that opens the thermostat is on the side away from the water flow and the thermostat on these models is not on top of the engine where it would heat up naturally so if you have any air bubble in the system the thermostat can stay cooler by closing more so it makes the car run hot. Anyway that's the theory. In fact it solved the problem immediately and the car runs around 210-220 now. If you drop the thermostat in boiling water you notice that when it opens the opening is much much larger than 3 or 4 little 1/8" holes so I dont see what it could hurt. (As long as you're careful when you drill). Of course YMMV.
Anyway that's it. Love my Cobalt again.
I got on here looking for an OBDII drive cycle to get ready for smog but also wanted to post a tip on overheating I came up with. I have a 2006 Cobalt with the 2.2 liter engine and after some engine work the mechanic could not get it to run under about 250 degrees. He put in 3 thermostats, finally including a chevy unit from the dealer, followed the bleed procedure, and still too hot. I finally had him just leave the thermostat out which made the car run around 150 and a trouble code for not up to thermostat temperature. That was fine until time to smog it. The solution I came up with may seem kind of extreme but I just drilled a few little 1/8" holes in the thermostat diaphram. I think that does two things, first it makes the system way easier to fill. Just take off the top hose at the engine and fill it up until coolant comes out at the top of the engine. Second, the piston that opens the thermostat is on the side away from the water flow and the thermostat on these models is not on top of the engine where it would heat up naturally so if you have any air bubble in the system the thermostat can stay cooler by closing more so it makes the car run hot. Anyway that's the theory. In fact it solved the problem immediately and the car runs around 210-220 now. If you drop the thermostat in boiling water you notice that when it opens the opening is much much larger than 3 or 4 little 1/8" holes so I dont see what it could hurt. (As long as you're careful when you drill). Of course YMMV.
Anyway that's it. Love my Cobalt again.
