Originally Posted by jr's3800

I haven't seen a write up on the thermostat replacement for the 87-91 bonnevilles either... But its fairly simple... On the 91, follow the top radiator hose to the thermostat housing next to the throttle body, it will look like an elbow of sorts, you may need to drain a little coolant out of the radiator... I have never bothered to drain the radiator to replace the thermostat, I just rine it all down after I'm finished and top it off with coolant.. Back to the program, there will be one bolt on the thermostat housing, it will need to be removed, after this the housing should be fairly easiy removed.. You should see 2 rubber rings one on the housing( basicly an oring seal) and one on the bottom of the thermostat housing, these rubber rings may need to be replaced...

Autozone and the like should sell the thermostats, but the Orings are a bit iffy sometimes, sometimes they have them, sometimes they don't... As for the thermostat there is a generation 2 thermostat, it costs around $6, I have to say its the best one I hve bought... It keeps the temps pretty much on the money... Also a good repair manual like Chiltons, may be of help for you... Its helped me a bit...

As for the throttle body cleaning, you don't really have to remove the throttlebody to give it a decent cleaning, but you will want to remove the MAF( Mass Air Flow ) Sensor, it will be a small looking black box on the throttle body, and it will have a 3 or 4 wire connector, you will not want to touch the wires on the sensor in any way, the sensor is super delicate... The reason you should remove it is because the throttle body cleaner can damage the sensor... To clean the throttle body you will need to remove the acordian tube duct that goes from the throttle body to the filter housing, after that you will need to carefully remove the MAF Screen, there will be a worm type clamp on the throttlebody, a good all should be ok to remove the clamp, but you will want to be careful when removing the MAF screen.. To clean the throttle body use Throttle body and intake cleaner( Made By STP )Sensor and plate coating safe, you can take a toothbrush and spray the inside of the throttle body while holding the throttle plate open, clean the throttle bore and the throttle plate with the toothbrush, spray the throttle bore and plate clean, once it looks good, reassemble everything and start the car, it may be a bit on the hard side to start but it will start... Let it idle for a bit to find its sweet spot, make sure everything has been put back in its proper place, once everything looks fine then its time for a test drive... Does this Help?


Jr ( Don )