TAMD41A Running Temp and Cooling System Questions

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bowler

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Hello all,

I have been experiencing a running temp problem on my port engine since new.

The temp guage reads 200 when pushed to WOT. However, no over heat alarms. An IR gun on the tsat housing shows temps around 85/86 degrees where it seemed to level off. Sadly, due the number of no wake zones I can't take it for an extended run until we are next at sea (which will likely be the next season). Both gauges above and below give inconsistent readings and appear accurate at low speeds but according to the IR gun read high when over 80.

Could this be the sender?

Since buying her I have rebuilt the water pump (which was leaking at the rear seal) and have replaced the seals on the heat exchanger which interestingly enough appeared pretty clean (perhaps not surprising as she has been in fresh water for the last 14 years) although a thorough clean in on the cards. I also noticed that the hoses where not lined up correctly on the end plate. The left image is after, right image before.

20190712_122638.jpg20190712_113146.jpg20190712_111628.jpg

The gauge downstairs always read about 10C higher than the one on the flybridge (which would climb slowly to 200 and appeared to be the more accurate of the two), but since this correcting the pipework they both climb to 200 quickly when pushed which seems odd, but the IR gun tells a different story so I am hoping it is electrical and a coincidence.

What would the effect of the hoses being lined up like this be? Running hotter I assume? Strange though as I never got an alarm even when they were like this and the gauges read high.

Moving forward.

Is 85/86 an ok running temp at high RPM, the manual says the operating range is up to 90 so this would be ok? I plan to swap the senders and see what happens, new ones seem to be over 100 quid. Then flush the system with rydlyme or similar to be sure.

Are there any other measurements for temp I should check with the gun?

Sorry for the ramble. All thoughts welcome.

D
 
Shouldn't the hoses align with the quadrants?
It is hard to tell from the pix also are there seals where the end plate sits against the three ribs that channel the flow?
There are manuals available for the 41 series engines if you look online.
 
bowler said:
Hello all,

I have been experiencing a running temp problem on my port engine since new.

The temp guage reads 200 when pushed to WOT. However, no over heat alarms. An IR gun on the tsat housing shows temps around 85/86 degrees where it seemed to level off. Sadly, due the number of no wake zones I can't take it for an extended run until we are next at sea (which will likely be the next season). Both gauges above and below give inconsistent readings and appear accurate at low speeds but according to the IR gun read high when over 80.

Could this be the sender?

Since buying her I have rebuilt the water pump (which was leaking at the rear seal) and have replaced the seals on the heat exchanger which interestingly enough appeared pretty clean (perhaps not surprising as she has been in fresh water for the last 14 years) although a thorough clean in on the cards. I also noticed that the hoses where not lined up correctly on the end plate. The left image is after, right image before.

View attachment 80559View attachment 80560View attachment 80561

The gauge downstairs always read about 10C higher than the one on the flybridge (which would climb slowly to 200 and appeared to be the more accurate of the two), but since this correcting the pipework they both climb to 200 quickly when pushed which seems odd, but the IR gun tells a different story so I am hoping it is electrical and a coincidence.

What would the effect of the hoses being lined up like this be? Running hotter I assume? Strange though as I never got an alarm even when they were like this and the gauges read high.

Moving forward.

Is 85/86 an ok running temp at high RPM, the manual says the operating range is up to 90 so this would be ok? I plan to swap the senders and see what happens, new ones seem to be over 100 quid. Then flush the system with rydlyme or similar to be sure.

Are there any other measurements for temp I should check with the gun?

Sorry for the ramble. All thoughts welcome.

D
Click to expand...

Hi, your coolant will boil and turn to steam between 110 and 120 degrees C (assuming your header tank pressure cap is maintaining the pressure) so unless the pressure cap is letting lots of boiling water/steam escape your engine is not overheating in a big way so the only problem you have is a faulty gauge. Is your water temperature alarm wired to a seperate sensor in the coolant circuit? If so, and it is not sounding, then that confirms. I assume the gauge on the other engine reads ok at around 85 so yes, swapping senders will be useful but first why not just extend the wires to the senders and swap them over so you can compare the gauges?

Www.solocoastalsailing.co.uk
 
End cap is on wrong looking at the angle on pic on right .
The 2 rubber hoses should be closest to the engine , the hose that goes to the exhaust elbow is also on the wrong outlet .
The pic on the left is correct
 
Check the electrical connections between sender and gauges and power. Any resistance causing voltage drop will also make the gauges read high.
 
Hi all,

Thanks for the replies. Yes, I believe there is an alarm but of course will have to double check! The boat is a Fairline Corniche for anyone who is familiar with them. I think volvopaul has had two.

I have already swapped the gauges to no avail hence my thought on the sender. Will swap and check the wiring.

I will be thrilled if that sorts it.

D
 
bowler said:
Hi all,

Thanks for the replies. Yes, I believe there is an alarm but of course will have to double check! The boat is a Fairline Corniche for anyone who is familiar with them. I think volvopaul has had two.

I have already swapped the gauges to no avail hence my thought on the sender. Will swap and check the wiring.

I will be thrilled if that sorts it.

D
Click to expand...
If your heat exchanger is piped as in the right side photo on your first post that’s the reason , basically the salt water passes through the cooler 4 times but how it’s piped now it only passes through half of it .
 
Thanks Paul.

That's how it was piped but now piped properly. I only noticed when I checked the anodes last month. I think the gauge/sender is a separate issue as both are still reading high compared to the IR gun.

D
 
bowler said:
Is 85/86 an ok running temp at high RPM, the manual says the operating range is up to 90 so this would be ok? I plan to swap the senders and see what happens, new ones seem to be over 100 quid. Then flush the system with rydlyme or similar to be sure.

D
Click to expand...
Manual says
Thermostat opens at 74-78C, 165-172F
Fully open at 88-92C, 190-197F
If temperature exceeds this but alarm does not sound then the overtemperature sensor may be faulty. Happened to me.
 
Hmmm. Good point. The alarm buzzer works but how can i test the sender in the dock? Can i ground it with the engine running or something?
 
Remove it, stick it in a pan of water and bring to the boil.
If it is open circuit when cold and closed circuit when hot or vice versa then it is working.
If there is no change between room temp. and boiling then it is not working.
 
Can you set your heat gun to Celsius? Sorry !
Gauges are pretty much not too accurate usually. My merc mpi shows 160+ on the gauge, but actual temp from the engine ecu sender shows 152.
You should be around the 85-90oC on that engine. Not sure if you are measuring in Fo ?
 
QBhoy said:
Can you set your heat gun to Celsius? Sorry !
Gauges are pretty much not too accurate usually. My merc mpi shows 160+ on the gauge, but actual temp from the engine ecu sender shows 152.
You should be around the 85-90oC on that engine. Not sure if you are measuring in Fo ?
Click to expand...

Sorry, I was jumping between units.

Gauge shows 95C but IR gun on the tstat housing shows 85/86C.

D
 
bowler said:
Sorry, I was jumping between units.

Gauge shows 95C but IR gun on the tstat housing shows 85/86C.

D
Click to expand...

I would imagine the outside of the housing would be cooler than the inside. Not sure the accuracy of an ir gun is such that you actually have a difference in temperature between both. Diesels tend to like higher temperatures, about 90c would be ok in my opinion. Temperatures locally within the engine will be higher than the bulk coolant temperature, cooling systems are pressurised to prevent local boiling in those areas and the subsequent damage the gas bubbles would cause.
 
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