Temperature issue

[Distant]

Hello from Distant.

Just had my perkins 4236 completely reconditioned. When I open valve to direct coolant through hot water tank,temperature increases,when it reaches 200 I shut the valve of and temperature drops back down to 185. I don't know how high it would go if I left valve open.

 

[Swfla]

Did it behave that way before engine work?

 

[Island Cessna]

Not much information here for remote troubleshooting but three thoughts for you:
1. If that is your temperature sender in the photo, with the water heater shutoff valve next in the same pipe, it could be that the actual coolant temperature does not change when the valve is opened. The increase could be due to coolant flowing past the sender when the valve is open, but the sender is in a blind pipe when the valve is closed.
2. The coolant flowing through the water heater is not being cooled nearly as effectively as the balance of the flow going through the heat exchanger. You could have too much coolant bypassing the heat exchanger via the water heater. Partially closing the valve would fix this. A globe valve is better for bypass coolant flow to bus heaters or water tanks as you can modulate the flow better.
3. Don’t forget that electric temperature gauges are notoriously inaccurate, and a different sender will give a different reading. Your 200 degree reading could be higher than the actual temperature, and hence less scary.

I would test with the heater valve cracked slightly, just enough to have flow, and see if the temperature stabilizes.

 

[Distant]

I had different engines before,did not have this issue.
I did open valve slightly to see if reduced flow would correct problem, but temperature still increased.
I am wondering if the location of the sensor is giving incorrect read out with valve open or closed,and which would be correct,valve open or closed. It is not actually in the head ,instead T'd into a line coming from the head

 

[Swfla]

With different engines, isn't it possible that the plumbing needs to be different? This sounds a lot more complex because of that. I suggest a pro to figure this out. I'd even talk to the shop that put this engine in because they didn't plumb it correctly and they should correct it on their nickel. Have you spoken with them?

 

[Distant]

Yes,did discuss it with them,and they don't understand why this is happening. However have recently discussed it someone who has been involved with marine engines for sometime,he' will look more closely at the issues and also will discuss further with those who did the work on the engine.
Thanks

 

[Swfla]

In person, tracing hoses and knowledge of different cooling setups is your best bet. Please keep us posted as we all learn from this type of situation. Cheers.

 

[Distant]

Thanks for your input....,cheers.
It would be interesting to see how someone with the same engine has their hot water tank connected.
Thanks again.

 

[Island Cessna]

Thanks for your input....,cheers.
It would be interesting to see how someone with the same engine has their hot water tank connected.
Thanks again.

I have a Perkins 4.236. My coolant for hot water tank circulates through a small heat exchanger on the hydronic heating system, which services the hot water tank plus the space heating. This makes no difference to what the engine cooling system sees, other than I may get a bit more cooling in the rare event that I use the engine heat for space heating. I leave both globe valves on the heating circuit wide open as I have never had an issue with overheating.

I do have two engine temperature senders. One located on the thermostat housing which serves the gauge on the flybridge. The second is located where yours is, serving the lower helm gauge. I do see a 20 degree lower temperature on the lower gauge, which I have never investigated, as they are both steady and consistent at all operating conditions. An IR gun on the head reads 185, which is what the upper gauge (sender on thermostat housing) reads.

For info I have the Bowman mani-cooler system. The engine is a 1999 vintage.

Photos below.

 

[Distant]

Thanks for the info.
Both engines recently reconditioned,right engine runs and indicates 20° cooler than left, sensors in same location,however will check them more closely. Still working on some issues.
Thanks again.

 

[Distant]

My engines are around mid 80'S but recently reconditioned. Have not checked the make of the heat exchanger ,but will do.

 

[Giggitoni]

Thanks for the info.
Both engines recently reconditioned,right engine runs and indicates 20° cooler than left, sensors in same location,however will check them more closely. Still working on some issues.
Thanks again.

Swap the sensors just for grins.

 

[Distant]

Maybe will do.
Thanks.

 

[DrissZougari]

Your issue sound like the water is not circulating through the water heater properly. Also, the location of the temp sensor looks like its giving you the temperature of the dead leg. I suggest that you check the location of the return leg from the heater back to the engine.
Regards

 

[Distant]

Thanks,will check return leg.

 

[OldDan1943]

Quick question and then I will observe.
Is the hot water heater electrically on, at the same time?

 

[Distant]

No,no electrical on to tank at same time.
Thanks.

 

[OldDan1943]

Hmmm restricted water flow, perhaps. Blow the coils of the hot water heater out.

 

[sunchaser]

Distant
Buy an IR gun. Your troubleshooting will be quick and accurate.

 

[Distant]

Yes,just recently started checking it all out,so will take all sugestions into consideration.
Thanks.

 

[Marco Flamingo]

Swap the sensors just for grins.

Or just swap the leads. Faster and not as messy. Might need some alligator test leads, always a good thing to have onboard. Somebody mentioned having a pro look at it. I've always opted for becoming the pro.

 

[Distant]

Thanks.....haven't looked at it lately,but will ,look at whole system again soon.

 

[ksceviour]

Airlock? If you’re losing circulation (valve open) the engine temp will increase and decrease when circulation is regained (valve closed). With a recent overhaul in the equation my suggestion is to make sure you have proper circulation through the water heater/hydronic heater system.

 

[timb]

i don't know if it matters but you may be letting the water flow needed for engine cooling go through the water heater my boat has a ford diesel but it has a flow control in the fitting in the engine that limits flow(to the water heater to keep engine flow /pressure normal . is it a missing valve that didn't get reinstalled? or is adjusted incorrectly?

 

[Distant]

Will check,for air in system. Have thought about to much coolant flowing to heater with valve opened,Will eventually take it ,run engine out and open valve just a little.
Thanks.

 

[ksceviour]

Will check,for air in system. Have thought about to much coolant flowing to heater with valve opened,Will eventually take it ,run engine out and open valve just a little.
Thanks.

The coolant flowing through the heater does nothing more than prolong the warmup time. Unless your heater has an electric element that's set higher than the engines thermostat everything should stabilized at about 180°F.

Without knowing the plumbing setup I would be concerned that metering the valve like that would restrict proper coolant flow through the engine.

 

[ksceviour]

Another possibility (after looking at the pic again) is that your engine is actually running hot. I would think the only way for that sender to read accurately would be when the valve is open. Otherwise it's out of the loop.

Is there a way you can bypass the water heater at the heater? If it runs hot then with the valve open you'll know it's a real indication and has nothing to do with the loop.

 

[Distant]

That valve is strictly controlling flow to the heater.
Yes I can disconnect hoses from the heater and then connect hoses to complete the loop. However the loop is complete now,coolant is flowing to the water heater and back into the engine,so you may be correct,the true reading is when valves are open.
Thanks

 

[ksceviour]

How did you make out with the temp?

 

[Distant]

I am checking out the stb engine. I ran a hose between the connections for the tank and ran that engine today,it seems unaffected no increase in temp., so will connect tank to that one.
The port engine without tank connected runs at 180.
Still a mystery why temp increases with tank connected.
Thanks for input.