Mercruiser Temp Question

[bryantjb3]

I have a mercruiser 5.7L 220hp. Last year the engine was running cool so in the off season I replaced the thermostat (160), and also the water pump. We took her out yesterday and I carried my IR gun to double check. Guage read about 175 and IR around engine head and pump was in 155 range. 175 was higher than I expected but my concern was when I shot the oil filter. It read 220. Does anyone have an idea what the oil temp should run or what is too high.

 

[Bondo]

Re: Mercruiser Temp Question

220* is the Bare Minimun for Oil temps......<br />Hot enough to Burn Off any water or Condensation.......<br /><br />220* to 270* are Normal Oil Temps.........

 

[trog100]

Re: Mercruiser Temp Question

certain parts of an engine are way hotter than the water temp gauge suggests.. good job u cant poke that ir gun inside the engine else u might really have a shock.. he he<br /><br />oil is heated by friction.. the harder u work the engine the hotter it will get.. some engines are fitted with oil coolers to prevent this happening..<br /><br />as it passes thru the main and big-end bearings it will be hotter still.. the hottest points would be at the main and big-end bearing themselves.. if it gets too hot there the bearing material actually melts just like solder.. your oil filter is probably the coolest part in the entire engine..<br /><br />i must admit to not knowing just how hot it can get thow.. but as bondo says it does need to be hot enough under load to boil off water and crap that would otherwise accumulate in it..<br /><br />trog100

 

[bryantjb3]

Re: Mercruiser Temp Question

Thanks for answering my question so fast. The temps you quote make me feel alot better. We probably will not go back out for another week or so but I plan to keep a close watch on the temps just in case. Thanks again for the help