5.7 GXI San Juan partially closed cooling running cold.

[Sand Man 1]

System installed this spring. Runs 135-140 degrees constantly. Doesn't rise to 160 even before thermostat opens. Never above just over 140. Kit included new thermostat. Tried a new thermostat this weekend. Went to Mercruiser type with baffle. If you idle around long enough it will go to180 at dead idle. As soon as you give it any rpm it drops back to under 140. I surrender. Any ideas?

 

[Sand Man 1]

Re: 5.7 GXI San Juan partially closed cooling running cold.

To be clear, we have used the thermostat that came in the kit all season. NEVER getting above 140. Just this last week we tried a new thermostat. With baffle. Idling around cove it gets to 180 and stays there. As soon as you give it ANY rpm it drops to 135 and stays there. Even just increasing rpm enough to go a few mph.

 

[Scott Danforth]

Re: 5.7 GXI San Juan partially closed cooling running cold.

first, get an IR thermometer to verify temperatures. the dash mounted gauge is highly inaccurate.

secondly, test the thermostat.

 

[Sand Man 1]

Re: 5.7 GXI San Juan partially closed cooling running cold.

All readings except the last time out idling around were with a gun. Don't see any reason to test both thermostats. Can't see them both being bad.