3126 thermostats

[markrinker]

Appears that thermostats were not changed when impellors were, and after-coolers tanked winter 2011-2012.

I'm seeing ~175port and ~190starboard when running the boat on plane at 2300-2400 rpm for extended periods. From a 'cool start', and running >2200rpm they will both run an even 170. However, go above that and once the starboard is 'heated' it doesn't drop back (even if you return to lower RPMs) until off plane and then temps fall back and even up both sides.

Nothing too alarming, but I thought I'd start with thermostats before digging any deeper, and see if they even up when running cruise RPMs of 2300-2400. Strainers are clean, impellors have ~120hrs and of course its the starboard side that is a PITA to pull and inspect...

Q: How hard are thermostats to get to and change out? I have to admit I haven't even spotted their location yet...

 

[peterkvs]

Assuming the 3126 is similar to the 3116 I have it is pretty easy. If I remember correctly you loosen the bolts that hold the coolant tank so you can move it out of the way and then disconnect the hose that runs from the heat exchanger to the top front of the block. The flange that hose connects to is removed and the thermostat is behind it. You will of course need to drain the coolant first. And you will need the thermostat and flange gasket.

When I did mine I flushed out the system with water and refilled with new cat ELC extended life coolant. The life of that coolant is 5 years.

Pete

 

[markrinker]

Agreed! The coolant tested okay, but is likely overdue for replacement. As always, its cheap insurance.