View Full Version : 454 MAG Temperature Problem

Roger P.
03-20-2006, 08:04 PM
According to owners manual - operating temperature should be 160 deg. F. My guage reads 180. It is not running hot. Is it the sending unit or the guage that's faulty (or something else). Where is the sending unit located?

03-20-2006, 11:08 PM

Are you RW or FW cooled? It makes a difference in the operating temp. Sender should be located on or near the thermostat housing. Your best investment will be a lasar pyrometer. This innexpensive tool (approx. $75.00) will prove invaulable over the life of your boat. It will give you an accurate accessment of engine temps, as well as locating hot spots which could be areas in need of attention.

Good luck


Capt William Myers
03-24-2006, 12:11 AM
for a 454 170 to 180 is the right operating temp. Guages in most boats are not spot on. As Rick said the only way to do it is to get a correct reading as he said. I would not sweat it. If its making power and exhaust smoke is light gray not black. Just run it. The guage appears to be good enough to watch for over heating. I have owned a lot of boats and the guages are never right you just get used to them

Dennis Dunlap
05-12-2006, 02:43 PM
"I have a similar question. I Have a temp laser and show around 160 degrees at base of temp sending unit however the temp on gauge shows about 180 & higher. Can't find any higher temp than 160 anywhere around the thermostat, however still think I have an issue. This "was" a salt water boat (now on Lake Erie) and question is could the intake be blocked around the thermostat housing and if so, would this be the only area inside the intake that would give me a problem?? I think I might have "stalagmites, stalagtites, (or what ever grows in caverns)inside the intake. Also, is there a specified length of the hose from the outdrive (Alpha 1) to the transom? This is a 454/330 HP 1987 Searay"