How to replace SS thermostat
Thread Starter
Senior Member
Joined: 03-08-2008
Posts: 303
From: los angeles
How to replace SS thermostat
Has this procedure ever been documented anywhere? My search ability seems to be failing miserably. I found one video on Youtube, but half the engine was already out so getting there was simple. I can see it, but it's not clear if I loosen the bolts what I'll find or what pieces I'll need or what I have to do to be able to get my arm there to replace the thermostat and any gasket that's required or what it all looks like.
I assume it's the thermostat not opening fully as it warms up when the engine is idling and cools off when the RPM gets higher. Heater on or off doesn't seem to effect the results much. If you at a light and it gets to 210, running through first ger will drop it to 199 or so pretty quick, I assume from the cold water in the radiator getting to the sensor. The coolant was a bit low, took about a quart in the engine. I think there's still a bubble somewhere as if I pull the cap and warm it up I have to remove 3 or 4 ounces of fluid so it's doesn't spill. I assume that's an air bubble expanding under the heat. We drove it on the freeway last night about 20 miles including up and down a mile of reasonably steep grade but there was no space to add more coolant today.
I assume it's the thermostat not opening fully as it warms up when the engine is idling and cools off when the RPM gets higher. Heater on or off doesn't seem to effect the results much. If you at a light and it gets to 210, running through first ger will drop it to 199 or so pretty quick, I assume from the cold water in the radiator getting to the sensor. The coolant was a bit low, took about a quart in the engine. I think there's still a bubble somewhere as if I pull the cap and warm it up I have to remove 3 or 4 ounces of fluid so it's doesn't spill. I assume that's an air bubble expanding under the heat. We drove it on the freeway last night about 20 miles including up and down a mile of reasonably steep grade but there was no space to add more coolant today.
Moderator
Joined: 05-01-2014
Posts: 8,511
From: California
I don't see anything in your post that warrants replacing the thermostat.
The only concern I have is that, even in these winter ambient temperatures, you're seeing 210* at a stop light. But that's not the fault of the thermostat.
Check out Oldblue's how-to on burping the cooling system. https://www.chevyhhr.net/forums/how-...-system-60614/
If you really want to replace the thermostat, it's no big deal. I had to loosen the big hose clamp to get better access to one of the bolts, but did not have to remove the hose. Put some electrical tape on your universal joint, so you can better control where the socket is going.
The only concern I have is that, even in these winter ambient temperatures, you're seeing 210* at a stop light. But that's not the fault of the thermostat.
Check out Oldblue's how-to on burping the cooling system. https://www.chevyhhr.net/forums/how-...-system-60614/
If you really want to replace the thermostat, it's no big deal. I had to loosen the big hose clamp to get better access to one of the bolts, but did not have to remove the hose. Put some electrical tape on your universal joint, so you can better control where the socket is going.
Administrator
Joined: 10-13-2011
Posts: 40,082
From: Welland,Ont Canada
An ‘08 SS hmm , if it’s the original thermostat, then yes change it and the coolant ! Dexcool should be replaced every 5 years!
Only use an AC Delco 131-158 180 degree thermostat and 50/50 Dexcool
Only use an AC Delco 131-158 180 degree thermostat and 50/50 Dexcool
Moderator
Joined: 01-23-2009
Posts: 26,532
From: Fredericksburg,VA
Just 2 bolts, remove them remove old t-stat replace with AC Delco 131-158 replace bolts. Real rocket science.
However, that is not the problem. The t-stats job is to keep the temp above 180F, not cooler. If it was a quart low you got other problems.
However, that is not the problem. The t-stats job is to keep the temp above 180F, not cooler. If it was a quart low you got other problems.
Senior Member
Joined: 03-29-2022
Posts: 1,241
From: Davison MI
Has this procedure ever been documented anywhere? My search ability seems to be failing miserably. I found one video on Youtube, but half the engine was already out so getting there was simple. I can see it, but it's not clear if I loosen the bolts what I'll find or what pieces I'll need or what I have to do to be able to get my arm there to replace the thermostat and any gasket that's required or what it all looks like.
I assume it's the thermostat not opening fully as it warms up when the engine is idling and cools off when the RPM gets higher. Heater on or off doesn't seem to effect the results much. If you at a light and it gets to 210, running through first ger will drop it to 199 or so pretty quick, I assume from the cold water in the radiator getting to the sensor. The coolant was a bit low, took about a quart in the engine. I think there's still a bubble somewhere as if I pull the cap and warm it up I have to remove 3 or 4 ounces of fluid so it's doesn't spill. I assume that's an air bubble expanding under the heat. We drove it on the freeway last night about 20 miles including up and down a mile of reasonably steep grade but there was no space to add more coolant today.
I assume it's the thermostat not opening fully as it warms up when the engine is idling and cools off when the RPM gets higher. Heater on or off doesn't seem to effect the results much. If you at a light and it gets to 210, running through first ger will drop it to 199 or so pretty quick, I assume from the cold water in the radiator getting to the sensor. The coolant was a bit low, took about a quart in the engine. I think there's still a bubble somewhere as if I pull the cap and warm it up I have to remove 3 or 4 ounces of fluid so it's doesn't spill. I assume that's an air bubble expanding under the heat. We drove it on the freeway last night about 20 miles including up and down a mile of reasonably steep grade but there was no space to add more coolant today.
BTW I do not see any reason to replace the thermostat.
Thread Starter
Senior Member
Joined: 03-08-2008
Posts: 303
From: los angeles
And then there's the unexpected twist. Decided I didn't want to do is so I took it next door to the auto shop. They decided there was nothing wrong but the digital gauge is reading high, but the analog one works fine. Weird, are there two water temperature sensors?
