2002 Chevy Impala (187,000 miles - I know she's near the end of her life). My car was getting overheated. There was no visible leak and no coolant dripping beneath the car. I topped off the coolant and it continued getting hot.
I took it to the shop and there was still no visible leak anywhere even as the car continued running and we revved the engine
, but there were signs of a previous (recent) leak (some dried dark orange splatter stains on the air filter box, near the throttle body and outlet pipe, etc. that wasn't there last week). The mechanic checked for leaks and topped off the coolant and checked to see if it was flowing out of the radiator
opening. There were no leaks and the coolant was flowing out of the opening. There was sludge on the radiator cap and in the reservoir.
The mechanic said he felt no pressure in the upper radiator hose. They said to "start" by replacing the thermostat (I purchased a duralast 180 thermostat). After they installed the thermostat, a leak cropped up along the radiator hose connection to the pipe near the throttle body. They then said I need to replace the pipe that runs along the engine (part #626-107, because the ends - where the bypass hose and pipe bolt connect to it - were corroded and breaking down, and they also said they needed to replace the intake manifold gaskets. I purchased an intake manifold gasket set and they replaced it.
I'm very upset because after I picked my car up (the shop was closed), the car started getting hot within minutes of me driving home and eventually approached the red portion of thermostat. The car is also running more rough than it was before they worked on it (almost feels like it's choking or struggling, with a fluttering type noise, when I drive), and there's fairly thick smoke coming from the exhaust
now (wasn't there before the repair).
They must have cleared the codes because I had a catalytic efficiency below threshold, and a P0128 Coolant Temperature Below Thermostat Regulating Temperature, but they're gone.
I don't feel they took the time to properly diagnose the leak, and just began indiscriminately working on the engine with an expensive job. In hindsight, I'm not familiar with Intake Manifold Gasket problems causing overheating. I'm hoping you can provide insight.