How to Install a Thermostat in a 1992 E 150 5.8 Engine

Ford's full-size van line, known as the Econoline series in 1992, offered several size and engine options. The E150 is the half-ton variation, and the smallest of the vans. The 5.8-liter Windsor was the largest gasoline powered engine available from Ford that year. This engine is liquid cooled, employing coolant, a radiator, fan, hoses and thermostat to remove heat from the engine. The thermostat's job is to open or close for coolant flow regulation based on engine temperature. Since thermostats are inexpensive, it's good sense to install a new one every time you perform cooling system work.

Instructions

1

Open the E150's hood. Make sure the engine is cold to the touch before proceeding.

2

Remove the air cleaner lid, air cleaner and air cleaner bottom from the engine bay and set them aside.

3

Follow the upper radiator hose from the top of the radiator to the thermostat housing, on top of the engine. Slide the drain pan below the engine so it's directly beneath the thermostat housing. Remove the two bolts holding the thermostat housing to the engine using a socket set.

4

Pull the housing off the top of the engine. If it doesn't come off easily, you may need to carefully tap the side of it a few times to loosen it, and then twist it off to break the seal.

5

Note the orientation of the old thermostat and then remove it from the engine. Shove a clean rag down into the thermostat well. Clean the sealing surface on the thermostat well and the thermostat housing with the gasket scraper and then wipe both surfaces clean with a rag.

6

Remove the rag from the thermostat well and insert the new thermostat. Apply a thin layer of Black RTV to both sides of the new thermostat gasket and lay it on the well, aligning the bolt holes in the gasket with the bolt holes in the well.

7

Lower the thermostat housing back in place, using care not to displace the thermostat gasket. Thread the bolts in by hand and then tighten them with the socket set; never try to start these bolts with the socket set or you risk cross-threading them which leads to major engine work.

8

Note the amount of coolant you lost when removing the thermostat housing. Open the radiator and pour that amount of a 50/50 mixture of coolant and distilled water into the radiator. Reinstall the air cleaner assembly and filter.

9

Start the E150's engine and turn the heater on full blast. Wait until the engine has reached operating temperature and top the radiator with the 50/50 coolant and distilled water mixture. Shut the engine off and reinstall the radiator cap.

10

Inspect the thermostat housing for leaks. Inspect again after 50 miles of operation and also check and top the coolant level at that time.