Sierra 142 Degree Thermostat KIT Original Equipment Mercury
( Old Style )
- Fits various Mercruiser V6, V8 small block and V8 big block raw water engines
- Kit includes 18-3551 142 degree thermostat, 18-2552 cover gasket, 18-2553 cover gasket, 18-2554 cover gasket, 18-7173 o-ring and 18-2917 housing gasket
- Replaces Mercury 807252Q4, 807252T4
- Replaces Mallory 9-43150
Make sure to use the Marine style thermostat and not an automotive style.
If you use an automotive style it will cause the engine to run very cool on the gauge but your exhaust manifold's will be very hot!