Urgent help with replace thermostat please.
 

Hi all,
I changed my 89 300 ce coolant this morning. I tried to replace the thermostat as well. I opened the housing and pulled the thermostat. No matter how hard I pulled, the thermostat not moving at all. Is there any trick to replace it ? Thanks.

I've had to take a screwdriver and pry em out of there before. Make sure you have a new thermostat and gasket.

Hi Eagatwork, I did try to use screwdriver and pry it out, no luck. I almost broke the thermostat (I brought the new one). I just do not know what to do next. Should I just broke the thermostat in pieces?

Spray it with some lubricant and use a very small screwdriver to pry on the rubber seal to cut it or move it out. I did it this way on my 420SEL and it worked. After you break the seal you will be able to remove the thermostat with your hand. Before that I tried turning it with pliers but to no avail.

Roman
87 300 SDL 158K
86 300 SDL 216K
86 420 SEL 227K
81 300 D 148K

The last 2 thermostats I replaced. '83 300D, '84 300CD both came apart while I was removing them. Quite a bit of scale around them. I took 2 screwdrivers, put one through the thermostat and the other put the handle in the outlet tube for the housing. You sould be able to force the thermostat out.