96 cooling system air bleed valve
Thread Starter
Drifting
Joined: Feb 2009
Posts: 1,302
Likes: 2
From: colchester CT
96 cooling system air bleed valve
I was just making one last check for air in my cooling system by opening the air bleed valve on the passenger side thermostat cover/housing. It is a 7mm bolt head screwed inside a female piece which is then screwed into the thermostat neck. I tightened it up a bit too much and broke the head off. I don't know if this is stock or not as the FSM said it should be a regular screwdriver used to open and close the valve. Can I just find a screw/bolt that will fit in there or do I need to buy a whole new thermostat housing with air valve? Just got done putting the whole new interior in and all new cooling hoses. I don't want to further complicate my problems by doing something hack and stupid and end up with coolant all over my opti. any help would be appreciated and if anyone has a few pics of their 96 throttle body area it would be helpful so I can figure out what is stock and/or missing. Thanks
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I was just making one last check for air in my cooling system by opening the air bleed valve on the passenger side thermostat cover/housing. It is a 7mm bolt head screwed inside a female piece which is then screwed into the thermostat neck. I tightened it up a bit too much and broke the head off. I don't know if this is stock or not as the FSM said it should be a regular screwdriver used to open and close the valve. Can I just find a screw/bolt that will fit in there or do I need to buy a whole new thermostat housing with air valve? Just got done putting the whole new interior in and all new cooling hoses. I don't want to further complicate my problems by doing something hack and stupid and end up with coolant all over my opti. any help would be appreciated and if anyone has a few pics of their 96 throttle body area it would be helpful so I can figure out what is stock and/or missing. Thanks
For now just buy a bolt, use a little teflon thread sealer around the threads and you'll be good to go.
GM used to sell the fittings, not sure if they still do or not but it's be worth a check.
Not a very good pic, but hopefully it'll help...
Thread Starter
Drifting
Joined: Feb 2009
Posts: 1,302
Likes: 2
From: colchester CT
Stock is a brass fitting and bleeder screw. If it has a bolt in it, then it was replaced at some point.
For now just buy a bolt, use a little teflon thread sealer around the threads and you'll be good to go.
GM used to sell the fittings, not sure if they still do or not but it's be worth a check.
Not a very good pic, but hopefully it'll help...
For now just buy a bolt, use a little teflon thread sealer around the threads and you'll be good to go.
GM used to sell the fittings, not sure if they still do or not but it's be worth a check.
Not a very good pic, but hopefully it'll help...
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
yeah, it was a bolt not a screw. problem now is that I broke the head off so I have to take the whole thing out using the bottom nut. I found one at ecklers. Thanks for the pic. one more question, on your throttle body, what is that line that is blocked off and has blue tape on it? It's just left of your thermostat housing, it would be bottom left of TB if you are looking head on at it. Mine is also blocked off as is the one on the driver side in the lower right on the TB. Are these just to block off coolant flow to the throttle body or is it stock? thanks
- The line on the left is the hard metal line that runs from the back of the passenger side cylinder head to the front of the intake. It now connects to a rubber hose that goes to the radiator. It used to connect to a small elbow shaped hose that went to the tb.
- The middle fitting is on the water pump and is where one of the heater hoses connects
If you look in the middle of the two, below and slightly to the left of the throttle position sensor, you will see the tb cooling line that is capped with a black rubber cover. That is where the rubber elbow I mention above ran.
The tb bypass is easy on the '96....remove the long rubber hose from the driver's side of the tb. Remove the rubber elbow from the passenger side of the tb and the hard line. Connect the long rubber hose to the hard line. Store elbow for future NCRS member
Thread Starter
Drifting
Joined: Feb 2009
Posts: 1,302
Likes: 2
From: colchester CT
okay. If you are looking straight ahead at my TB, the line on the lower left hand passenger side is blocked off, just plugged. The line on the lower right hand driver side is blocked off, just plugged. They don't connect to anything. I am just trying to understand what they are supposes to do or if they are supposed to be plugged. Not really sure what is going on
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
okay. If you are looking straight ahead at my TB, the line on the lower left hand passenger side is blocked off, just plugged. The line on the lower right hand driver side is blocked off, just plugged. They don't connect to anything. I am just trying to understand what they are supposes to do or if they are supposed to be plugged. Not really sure what is going on
Leave it be and you'll be fine
Thread Starter
Drifting
Joined: Feb 2009
Posts: 1,302
Likes: 2
From: colchester CT
Someone already did the tb bypass for you. From the factory, the coolant lines connect to the tb as I described above. Having coolant run thru the bottom of the tb prevents icing on the blades which can happen under certain weather conditions. It's overkill on the part of GM. I've never heard of anyone having icing issues with their tb. Mine has been bypassed since the car was nearly new and I've lived in the midwest....cold winters, lots of humidity in the summer, every weather condition you can imagine in between...as well as the west coast, all without issue.
Leave it be and you'll be fine
Leave it be and you'll be fine
Race Director
Joined: Oct 2005
Posts: 11,772
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
But I sure do remember the days when my Holley 4-barrel would do it.
Didn't take extremely cold temps either. High humidity and temps around freezing was all it took.
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