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LS Swap Coolant Temperature Sensor Sending Unit Adapter M12 1.5 to 3/8 NPT LS1

In stock
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Male M12-1.5 to Female 3/8"-18 NPT Adapter

This adapts SBC/BBC (3/8" NPT) coolant temperature sensors to fit into LS series cylinder heads

  • Compatible with: all GM LS Series Engines
  • Made in Wichita, Kansas from aerospace grade, USA produced, billet aluminum
  • Includes: 1 aluminum adapter, 1 sealing washer
  • Will fit sensors with .85" length, measured from probe tip to the outer edge of adapter. Most aftermarket gauges will use a 3/8" NPT thread adapter (usually included with gauge)

More Information

Bullet Point 1 Factory LS cylinder heads are machined with metric M12-1.5 coolant sensor ports, so your factory Small Block Chevy sensor won't thread in to them. This adapter allows you to keep your original sensors and integrate them into your swapped LS engine.
Bullet Point 2 Adapter has a female 3/8" NPT port, .85" deep. Refer to thread chart to check your correct fitting size.
Bullet Point 3 Made in Wichita, KS from aerospace grade, USA billet aluminum
Bullet Point 4 This adapter will fit all LS series engines.
Bullet Point 5 Adapters are sold individually, and include 1 sealing washer
Manufacturer Part Number 551179
UPC 656729846810
Weight 0.180000
ICT Manufacturer ICT Billet
United States United States
Length Inches 2
Width Inches 1
Height Inches 1
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WARNING - This product can expose you to chemicals including lead, which is known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to


ALUMINUM: Most of the aluminum alloys used today contain some level of lead, usually less than .1%. Lead is known to the state of California to cause cancer and reproductive harm. Most aluminum alloys are physiologically inert in their solid form, and the lead is contained within, however user-generated dust and/or fumes may pose a hazard if inhaled or ingested. Heating beyond a certain temperature may also provide avenues for exposure.


STEEL (steel bolts):  Steel is an iron alloy with several metals including Nickel and Chromium. Both Nickel and Chromium are known to the State of California to cause cancer and reproductive harm, respectfully. This warning applies to stainless steels as well.