Okay, I have posted about this problem several times, but I am going to post another one of the same thing. My car runs like crap. It stumbles while driving and stalls but starts back up after a few cranks. It is idling rough and it is getting very very hot. I am going to replace the optispark because it looks awful so hopefully that fixed the stumbling. I drained the radiator and flushed it because it was gross. I think there is sludge in the engine. So I figured I might as well clean out the sludge since I'm going to redo the optispark. Does anyone have any tricks to changing the optispark and cleaning out sludge? By the way, I just changed the thermostat. Thanks!

 

how is the oil looking??? sorta milky? are you losing coolant?

 

The oil isn't milky at all. Its not a blown head gasket, that was my first thought too.

 

best to get some flush additive and follow direction. once done with that take the radiator out and run water threw both ways. take the thermostat cover off and remove the thermostat and run water threw the motor both ways. take the heater hoses off the water pump. hook your garden hose to one and turn on slowly and not to full open (heater core is made to withstand 25 lbs of pressure normal house is usually 50lbs or more) and see how the water comes out. if its coming free and the core appears to be unplugged open a bit more. then switch to the other hose and do it again. some lt1s will have a oneway valve or a restrictor valve that will not allow much water threw and you may have to try and get the hose off at the firewall and do it that way. once done there put er back together and add a gal of straight antifreeze and fill to full with 50/50 antifreeze and water. then bleed several times.