I have tried the search feature and the sticky and looked there before I posted this.
2005 LS V8 124k. Some background, in 8/2011 the t-stat housing broke at the nipple inside the house that the t-stat uses to push against to open up. replace the housing and t-stat with one from O'Rielys. Car ran fine through the rest of the summer here in GA even took a trip to NYC in September over Labor Day weekend and it ran great. In the past two weeks I have noticed after driving the car for about 20 minutes and coming to a stop i will here the engine cooling fan coming on high and the heat "hotness" will decline. Start to move again and the cooling fan seems to turn off and the heat returns to normal. The temp gauge on the dash will barely raise above the 9 o'clock position when driving. Hooked a scan tool up to it and when the cooling fan is running the coolant temp is 238F if you get the engine speed up to about 2,000 rpm the temp comes down to 224F and the fan shut off. If you touch the upper radiator hose when the engine is warmed up it is extremely hot, when you touch the t-stat housing it will be cool to the touch.
I am thinking that the radiator is clogged. If I understand the cooling system flow the t-stat controls the return flow from the radiator which is the exact opposite of how other engines operate. I have tried to bleed the cooling system multiple times and it seems to bleed out correctly, now having said that it seems to need coolant added to it before each time it's being bled. The other thing i noticed tonight is that the upper hose seems to be very "hard" to press when the engine is running like something is either pressurizing it or it's flow is restricted.
I am beginning to wonder if the degas bottle is leaking after reading the threads on this but i don't think that covers my whole problem.
Any ideas would be appreciated as to where I should look to sole this problem as it will only get worse when spring gets here.
Thanks
2005 LS V8 124k. Some background, in 8/2011 the t-stat housing broke at the nipple inside the house that the t-stat uses to push against to open up. replace the housing and t-stat with one from O'Rielys. Car ran fine through the rest of the summer here in GA even took a trip to NYC in September over Labor Day weekend and it ran great. In the past two weeks I have noticed after driving the car for about 20 minutes and coming to a stop i will here the engine cooling fan coming on high and the heat "hotness" will decline. Start to move again and the cooling fan seems to turn off and the heat returns to normal. The temp gauge on the dash will barely raise above the 9 o'clock position when driving. Hooked a scan tool up to it and when the cooling fan is running the coolant temp is 238F if you get the engine speed up to about 2,000 rpm the temp comes down to 224F and the fan shut off. If you touch the upper radiator hose when the engine is warmed up it is extremely hot, when you touch the t-stat housing it will be cool to the touch.
I am thinking that the radiator is clogged. If I understand the cooling system flow the t-stat controls the return flow from the radiator which is the exact opposite of how other engines operate. I have tried to bleed the cooling system multiple times and it seems to bleed out correctly, now having said that it seems to need coolant added to it before each time it's being bled. The other thing i noticed tonight is that the upper hose seems to be very "hard" to press when the engine is running like something is either pressurizing it or it's flow is restricted.
I am beginning to wonder if the degas bottle is leaking after reading the threads on this but i don't think that covers my whole problem.
Any ideas would be appreciated as to where I should look to sole this problem as it will only get worse when spring gets here.
Thanks