1976 1977 1978 1979 1980 Cadillac EFI Air - Coolant Temperature Sensor replaces GM 1609968 /AC Delco 213-188 / EL31 Hewitt Industries PN 021-104 / Bendix 1181447 I have seen other eBay listings where these are referred to as MAP sensors (*See note below regarding 1975 and early 1976 Cadillacs using originally using PN 1606011 with flat blade connection)

This is a replacement for GM PN 1609968 also known as AC Delco PN 213-188 and Bendix PN 1181447. Two sensors are used per car; one for the coolant and one for the intake air (Coolant and Air sensors are the SAME part number). Both are threaded into or near the intake manifold. This offer is for one replacement sensor with the original style OEM connector. I tried to sift through the applications to the best of my knowledge. You should verify your application. In 1980 these were only used on the 5.7L (350 cubic inch with California emissions option CA only). If you have a 1976 to 1979 Cadillac and it has fuel injection this should be the correct sensor. For 1976 early cars the OEM connector may be different (see additional detail below). I have not been able to confirm if the same PN was used on the diesel 5.7L for a similar function. The note in the GM parts manual lists 1980 as ALL (350-8)

I own one of these cars myself. If the coolant temperature sensor goes bad you will have issues with cold starting. I researched the sensors and I replaced the original sensing device with a modern alternative with the intent of improving the durability. Electronically the resistance curves follow extremely closely in the most critical temperature range. The wire is GXL multi-strand all Copper wiring (not Copper clad Aluminum). The sensor housing is custom made and is one piece brass. One of the failure modes of the original was due to a leak between the bulb and housing. Efforts have been made to allow the internal sensing element to maintain thermal freedom.

My original is shown for reference only in some of the photos (Not being sold as part of this offer). You will receive the new replacement part as shown which includes the following:

-Sensor "plug-and-play" direct replacement (1 pc which includes the assembled housing, wire, OEM plug and terminals assembled)

The sensor which this replaces is known by several PNs and names depending on the seller and manufacturer. Some names/ PNs include: EL31 Hewitt Industries PN 021-104 GM 1609968 AC Delco 213-188 Bendix 1181447 This is a new replacement but it is not NOS

This sensor varies in resistance based on temperature. You can easily test your sensor prior to even removing it. There are some rare cases where the sensor is good but the terminals on the ECU have some corrosion preventing the ECU from getting a signal. I encourage you to test your sensors before you buy a replacement.

The wiring harness side mating connector is often brittle after years of service. I do offer an OEM mating connector assembled with terminals (contact me as I have not listed it here yet).

*Note: These will also work on the 1975 and early 1976 Cadillac EFI cars, which used sensor PN 1606011, but for the 1975/ early 1976 (see below) you would need to update/change the wiring harness side connector as well (or splice in the new sensor before the factory connection). The sensing part of the sensor is the same in 1975/early 76 but Cadillac used a rectangular plug with flat blade terminals instead of the round one pictured. I have the mating connectors needed for the conversion available. My understanding is GM moved to the round connector because they were better at preventing moisture from getting inside the connection (under hood moisture had the potential for corroding the terminals).

If you have a 1975 or early 76 with the flat blade style connector PN 1606011 I and maintaining the original connection is important to you I can very likely move your original connector to a new sensor (avoids splicing). If you prefer that option please contact me before buying. You would need to send your original to me first.

If you prefer a more updated Weatherpack connector I also have them available to adapt the car to a Weather-pack connector. Please ask about this option before buying.

According to the GM parts manual the applications using the older 1975-76 version versus general 1976 and newer PN are defined below. There was also an Adapter GM PN 1605641. I suspect that allowed the newer 1609968 work directly on the older 75-early 76 cars without changing the wiring harness side connector.

1606011: Used on 76 K on cars before VIN 480001

1609968: Used on 76 K on cars after VIN 480000

1609968: Used on 76-77 C,E (Also see note** below)

1609968: Used on 77 K W/EFI

1609968: Used on 78-79 ALL series W/EFI