Bankswood

Ok, so I'm riding down the road and my sc 400 has been running great. Stop at a light and see my temp gauge pegged at hot. Pull over and steam and coolant leaking out of upper hose. Have the car towed to my local shop where they pressure test for coolant leaks. They put new clamps on both ends of the upper hose, refill with coolant and go for a test drive. Car overheats again. During all this time engine is running smooth just getting to hot. Think maybe there is air in the system so we bleed the system add more coolant and go for a ride, still over heats. Now we are pretty sure the thermostat is stuck so we let the car cool then replace the thermostat. Crank the car and it's starts misfiring bad, like maybe 2 or more plugs are misfiring. Check the codes and it's 13 (rpm signal), WTF? Any suggestions on what might have happened in that small widow of time? Remember, the car was running great just had a overheating issue.

Bankswood

Nevermind, ended up being a blown head gasket.

Htony

Pressure test did not catch it? Or they put exhaust gas detecting dye in the water to catch it?

Bankswood

before we replaced the thermostat is would run fine but over heat. When we pulled the thermostat is was stuck closed. Once we put the new one in it opened up and allowed coolant into the block and the coolant leaked into several of the cylinders. Makes me sick. I bought this car 5 years ago and one of the first things I did was replace the thermostat because it was stuck open and the car would not reach running temp. 5 years and 80,000 miles I should have replaced it. This car has been a joy to wrench on and I learned so much. Before I blew the head gasket it was running as smooth as ever. 201,500 and I thought 300,000 was in the future. Even though I think I could pull the heads and have them machined I'm just to old to mess with that. I have really enjoyed this forum and the members have been great. Best of luck to all you young guys and keep the 300 and 400 on the road.