W126

I have a 1984 300SD & it has developed a "groaning" sound when I turn right. I jacked it up & with the car running turned the wheel, no sound (most likely because it does not have the weight on it). I grabbed the tire I turned the tire hard manually & got a little noise from what I believe to be the "Guide Joint" on the top of the Steering knuckle. It looks to be in great shape. Any tips to solving or isolating the problem?

85 300SD 231,000 - bought with 180,000 in Oct 2005 - used for communting from Tennessee to Maryland and back a few times each month. Just useless FYI!! Problem is.. at low speeds taking off, it can hardly get out of it's own way especially with A/C - was going to give this to my son when he gets his license but i'm a little worried it is too slow and he'll have no power to get out of trouble if he pulls out in front of someone. i hooked up a pressure gauge between the switchover valve and the line to the ALDA. when taking off i get 1-3 psi until about 2500 rpm when the pressure starts climbing. at about 3000 rpm i'm getting 7.5 psi. is this right?

Whats the proper way to bleed the coolant lines for an 84 300SD. I have just acquired an 84 300 SD and have put in a new thermostat. I turn the car off when the temperature gauge is just shy of the mark between the 80C and 120C (I assume this is 100C). There is also no heat out of the heater where there was once before. So I probably still have air in my collant lines. What is the proper way to bleed the coolant lines? As an aside question, is there a way to tell if there is air in the coolant line versus the thermostat being bad?