P0172
Senior Member
Joined: 03-18-2018
Posts: 148
From: USA
Like I was telling Blue, thermostat is replaced and added marvel mystery oil to the oil change. Got all air out of system and temp up to 180.
Took stuff apart again and still no vapor coming from valve cover area. Used my air compressor which is stronger then works and it made some vapors come out. Still couldn’t figure out if pressure was blowing out of system or around my air hose nozzle. As I was putting all intake stuff back I noticed valve cover had some oil on it and looked like it wasn’t tight all the way. So tightened it and snap bolt broke off. Still not sure why that was loose. So now I have noticed a possible valve cover leak and now have a bolt broke in the head! Not sure how I will get the bolt out. No way the valve cover gasket could be causing my P0172 code. Hopefully that’s just the thermostat and the valve cover valve that’s acting clogged which marvel should clear that up.
Took stuff apart again and still no vapor coming from valve cover area. Used my air compressor which is stronger then works and it made some vapors come out. Still couldn’t figure out if pressure was blowing out of system or around my air hose nozzle. As I was putting all intake stuff back I noticed valve cover had some oil on it and looked like it wasn’t tight all the way. So tightened it and snap bolt broke off. Still not sure why that was loose. So now I have noticed a possible valve cover leak and now have a bolt broke in the head! Not sure how I will get the bolt out. No way the valve cover gasket could be causing my P0172 code. Hopefully that’s just the thermostat and the valve cover valve that’s acting clogged which marvel should clear that up.
Administrator
Joined: 10-13-2011
Posts: 40,097
From: Welland,Ont Canada
Here’s a how to get the valve cover off
https://www.chevyhhr.net/forums/how-...er-2-4-a-8554/
As for the broken bolt you might be lucky and have enough to grip and turn out with a set of vide grips or a pair of pliers, you might have to drill into the centre of the broken bolt and put the drill in reverse, sometimes that will unscrew it.
https://www.chevyhhr.net/forums/how-...er-2-4-a-8554/
As for the broken bolt you might be lucky and have enough to grip and turn out with a set of vide grips or a pair of pliers, you might have to drill into the centre of the broken bolt and put the drill in reverse, sometimes that will unscrew it.
Senior Member
Joined: 11-16-2021
Posts: 622
From: MN
Better off using a reverse twist drill bit to drill it out. Other option is to drill it oversize and use a heli-coil or thread insert to make it back to stock size. There are a number of different products to remove broken bolts on the market.