Mercuiser 5.7L Temp Gauge Reads about 178 with 160 degree Thermostat-gctid816756

[Bigbryz]

I called the mechanic that just put this motor in, and, he says that lots of Bayliner gauges read high,

and, he had verified the 160 degrees, I told him the Flybridge I had for 18 years always readt exactly 160,

Anybody else heard of this? it doesn't get any higher than that, and, always sits at the exact same spot when cruising.

bigbryz

[builderdude]

Mine is the same. Gauge reads 180 + ish but when I hit various areas of the engine with my IR temp gun the hottest area (base of t stat) is closer to 158. Get yourself one of those temp guns from harbor freight to verify your temps.

[yachtman]

160┬░ is when the thermostat opens up that doesn't mean that is the temp the engine runs at. My engines run at 170┬░ and 175-80┬░ port and starboard. If it start pushing 185+ or raises from previous normal temp that is when you should be concerned.

[bucluv]

all my byliners with the 160 stat always read 175 on the nose,,,,, but now with the 160 on my new bayliner I'm getting up to 190 on the gauge & risers getting hot & everything is new. smh...just put in a 140 & now stays at 160 on gauge

[pgiconch]

Just got a 98 Ciera 2655 with the 5.7 package and the original guage. The temp guage read 175 all the way home from the launch point. Can't say what thermostat is in it. In warm Florida shallow water (kinda like bath water this time of year). It didn't seem unusual for a V8 to be running at 175. My Vette (similar Chevy small block) often runs at 200 here in the FL heat.

[yachtman]

A new engine may run a little hotter. There is a lot of break in friction going on. A car engine runs somewhere around 200 at times splits not going to kill a boat engine to get to 200 . Tbe issue is when it does get that high something is wrong and it needs fixed asap.

If it goes above 200┬░ and starts to blow a lot of steam better shut it down. At that point heads can start to warp. If a engine is run hot to the point it dies well then the possibility that major damage has occurred is real. If it dies it is probably because it seized. Rings can break rods can bend valves can be damaged heads can crack and warp cylinders can be scored.

[MikeACY]

Same here as what the others have said. My 2011 2855 5.7 MPI has a 160 thermostat, but reads 180 on the helm. A shot with my IR gun shows temps are normal around the engine.

One thing that helped....I drilled 2 - 1/8th in holes in my thermostat at the beginning of the season, and the temp holds steady at 180. Before it would fluctuate between 180-200 without those holes.

Mike

[706jim]

My gauge reads just above 175. No idea what thermostat is in there.

[Saturday288]

My 288 with a 5.7 MPI has a 160* stat...upper & lower helm temp gauges read 180-185, yet MercMonitor shows 161* when running at cruise

[Redwngr]

WHEN DOES A THERMOSTAT START TO OPEN?

The thermostat starts to open at the rated temperature, plus or minus 2 degrees (F).

WHEN IS A THERMOSTAT FULLY OPEN?

The thermostat is usually fully opened at 15 - 20 degrees (F) above the opening temperature.

http://www.stant.com/index.php/engli...rmostats/faqs/