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Ir temp reading dilemma

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Northwest206

New member
After servicing my 1980 mercruiser 470, I decided to take ir reading on my motor. Every where is checking out normal around 155Ish but when I point the laser towards the link between head & exhaust manifolds the reading goes up to 220 highest reading. Is this something I should worry about? This readings were taken on muffs, impeller has been changed.
 
johnnygjr said:
How warm is the water exiting the exhaust, If you can keep hand in it indefinitely your fine.
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All readings are normal below 155, exhaust manifold, intake manifold, head, heat exchangers & rubber hosings, exhaust elbows etc. Only just those sections were head & exhaust manifold are areas where thr heat is passed 200+...I guess normal temp on running speed can get up to 175 for these type of engines, but Im just a bit curios as to why that's the only area were the reading is above 200's. Need exchange my temp sensor or gauge as their faulty & not working at the moment
 
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I'm actually a bit surprised that it's that cool! No cooling jacket there, since those points are only indirectly cooled, i.e., are mechanically connected to parts that are water cooled. All the points that you indicated had 155 temp are directly water cooled and effectively run at or near (offset) the actual water temperature in the engine. Not to worry.
 
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sandkicker said:
I'm actually a bit surprised that it's that cool! No cooling jacket there, since those points are only indirectly cooled, i.e., are mechanically connected to parts that are water cooled. All the points that you indicated had 155 temp are directly water cooled and effectively run at or near (offset) the actual water temperature in the engine. Not to worry.
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They are showing surface rust, so maybe it could use some bolstering from a machin shop, but their holding pressure and no signs of leaks. Im going to take a lake run and perform another ir temp reading.
 
On Mopar small blocks, the short length of metal between the head and water cooled manifolds always rusts. To me, that means it gets hot enough to burn the paint off, hence the high temp readings.

Jeff
 
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