Engine temperature seems cool

[Sergy]

Engine temperature
Hi everyone I have a Volvo Peta 62 hp that runs fine but I have a concern that the temp. Is not getting hot enough. It usually runs at 165*f to 170*F if worked hard. This is with a new temp sending unit. I have a separate temp gauge with magnet that sticks to head and it also indicates 155 * F
I would like to see 186*F The previous owner had a new thermostat installed a couple of years ago, so I do not suspect it.
1- The average water temp. Here is 48*F with a new heat exchanger installed is it possible that the volume of cold water through the heat exchanger does not allow the engine to heat up to 185*F
2- I thought of partly closing the 11/4” sea cock valve to restrict the amount of cold water going through heat exchanger but I figured I better ck with the experienced cursers first
3- Any Ideas or recommendations appreciated
is 165*F OK

[skipmac]

Hi Sergy,

I would check the thermostat. Even if relatively new they can fail. Have not done this in a while so assume the design of thermostats has not changed and this will still work.

Put the thermostat in a pot of cold water with a thermometer that reads to at least 212F (100C). Slowly heat the water and watch the thermostat and check the temp when it opens.

I would not restrict the flow of cooling water. Too easy to burn up the engine.

With 48F water temps you might try a thermostat rated at a slightly higher temp.

[delmarrey]

You can install a bypass line with a metering valve in front of your heat exchanger, routed to the exhaust, to slow down the rate of water passing thru the exchanger.

I had the same problem. I even went to a 190º t'stat and it still wouldn't get above 120º. But I'm in the colder climates right now and may end up closing the bypass when in the tropics.

BTW- Is this the same Sergy that I talked to on the phone a few years back about Clippers?

[Sergy]

Thanks guys for your advise. I had another thought the sending unit is not on the head or block but in the coolant just below the (looks like pressure cap on radiator) which would lead me to believe that this coolant is waiting for thermostat to open so it can enter the block and cool the engine ???
If this is correct then it would make sense to have cooler water temperature than what the engine temp. Is
Any thoughts
Sorry delmarrey though we are neighbours we have not spoken on the tel.

[Cheechako]

maybe talk to Volvo about it. If it's a "recent" engine I'm pretty sure they want it to run hotter than that. Sounds like the previous owner may have had the same issue and tried the T stat.... possible to put a restricting valve on the "out" side of the heat exchanger?.... forcing the water to flow slower through the exchanger?

[Sail Warehouse]

A couple of thoughts;
1. Does the engine coolant also run through a water heater heat exchanger? That will make it run cooler. I have twins and the engine that runs through the water heater always runs around 10 deg cooler.
2. I would recommend investing $35 in a handheld Infrared Thermometer to get an accurate read on the real temp since you are getting different readings. In the long run you may find like i did it is more useful than expected

Jim