Thought I’d post my results.
So like my Bonneville, which also had a leaking thermostat, my 1988 Caprice has a small leak now as well.
Both had the housing with the EGR vacuum plugs on them, but the Chevrolet has a coolant temperature sensor as well.
Because a replacement thermostat housing with the plugs and sensor, is twice the cost of what a normal one would be with only brass fittings- I decided to see how I could unplug the sensor, but have the check engine light remain off.
After some research, I discovered for LS engines a chart that shows resistance values for the sensor, and what ohms a healthy operating temp is determined to be.
Since I couldn’t find one for regular SBC’s, I decided to guess a range of what might work.
It became clear that between 600-1000 ohms was a good place to start, so I tried 1 kilo ohm- and the check engine light is back to off.
Now code 15 is still in the ECM, but so far the light hasn’t come back.
So like my Bonneville, which also had a leaking thermostat, my 1988 Caprice has a small leak now as well.
Both had the housing with the EGR vacuum plugs on them, but the Chevrolet has a coolant temperature sensor as well.
Because a replacement thermostat housing with the plugs and sensor, is twice the cost of what a normal one would be with only brass fittings- I decided to see how I could unplug the sensor, but have the check engine light remain off.
After some research, I discovered for LS engines a chart that shows resistance values for the sensor, and what ohms a healthy operating temp is determined to be.
Since I couldn’t find one for regular SBC’s, I decided to guess a range of what might work.
It became clear that between 600-1000 ohms was a good place to start, so I tried 1 kilo ohm- and the check engine light is back to off.
Now code 15 is still in the ECM, but so far the light hasn’t come back.