To keep the engine temperature the same in all weather conditions, engines have thermostats.
On a water cooled engine, the thermostat blocks off the water flow to the radiator until a certain temperature is reached (usually 165 to 195 degrees). As the motor warms up, a paraffin pellet in the thermostat expands against a piston in the thermostat, pushing it open and allowing water to flow through the radiator. On a very cold day, the radiator may cool the water jacket of the engine too much. The thermostat will then close a bit, reducing the flow of coolant through the radiator and thus maintaining a steady operating temperature. .
When an engine is overheated, the seal on the paraffin pellet is compromised, and the thermostat often fails shortly thereafter. They also fail from corrosion, and wear from many many cycles.
A motor with a bad thermostat will run fine for the first few minutes, then overheat rapidly. Often it will make a rumbling, gurgling, boiling sound: like a steam pipe knock, if you've ever heard one of those.
Below are pictures of a thermostat replacement in a Jeep Cherokee 4.0 Liter Motor.







The Economechanix Cyber Mall
We also serve the surrounding communities of Alachua, High Springs, Hawthorne, and Newberry!
Thank you for visiting the ECONOMECHANIX WEB SITE. Please feel free to comment. We also serve the surrounding communities of Alachua, High Springs, Hawthorne, and Newberry! Gainesville has been my home since 1974, and I've loved Gvl and the Gators since I came here in the fall of 1974 to attend the University of Florida. I loved it so much I stayed and opened my car repair business. Originally it was out of the back of a 1963 Chevrolet wagon, but in 1977 a fellow mechanic and I opened an auto repair shop with actual walls, etc. I stayed in the same location for 26 years, and recently moved my operation to property I bought 15 miles east of Gainesville. I am doing most all the repairs myself now, having reduced my overhead from $1500 per month to practically nothing. I do work by appointment only. I mostly work only on my established customers cars, but I will occasionally take on new clients. E-mail me and I will either make arrangements to look at your car, or I will recommend you to someone who will.
George G. Scott, Jr.