I have an 1988 CD28 flybridge w/ the Volvo TAMD41A, 200 hp diesel. I have owned the boat for 3 1/2 yrs. The heat exchanger core was removed just before I bought it and "boiled" because the previous owner was having overheating problems. I have had no overheating problems although the engine does push the limit 205 degrees and the over heat alarm starts to "sqeek" (meaning not fully on) when I run at WOT (3800 rpm) for more than 5 minutes. I run at this speed rarely, but I'm concerned as the overheat alarm suggests I'm on the verge of overheating. Is this normal operation in your experience? What temp do your boats run at? At cruise speed (3350 rpm) the coolant temp is 185 all the time.
Thinking about preventive maintenance I'm wondering about pulling the heat exchanger and having it boiled again? Can I / Should I use some the cooling system flushing stuff sold in autoparts stores to clean the system on an annual basis. I want to replace the antifreeze this year as it's been 3 yrs. The manual says to replace it yearly I believe.
I may have to pull the heat exchanger this season anyway as my hotwater heater looks like it's starting to leak and I fear it will need replacement. As far as I can tell the only way to replace it is to remove the engine heat exchanger to make clearance.
So, I would appreciate your thoughts and comments on :
1. Normal operating temperature and WOT operating temp
2. Removal and Replacement of the engine heat exchanger,
(I'd love to get a good Volvo service manual. But the two flimsy manuals "Owners" and "Shop" they publish don't address this.) Can anyone talk me through this? I'm not a novice mechanic, but this is my first diesel. I'm also a bit afraid of some Volvo idiosyncrasy that may not be obvious.
3. Any experience replacing the domestic hotwater heater. Any experience on a good replacement brand or model.
Thanks
Tony
tonyraymond@digital.com
Heat exchanger, Volvo TAMD41
Moderator: Jim Walsh
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Tony Raymond
Re: Heat exchanger, Volvo TAMD41
Tony,
If you don't have a data sheet for the TAMD41, you need to get one from your Volvo marine dealer. Take a look at the speed/power curves for your engine. The main curve you are interested in is the torque curve. It will be a "hill shaped" curve and you want to set your cruising RPM at just after the peak. This will give the best fuel and least stress on the engine. This curve will also be affected by your choice of prop ( diameter and pitch ). For most of the diesel pleasure craft engines I've looked at, the torque curve peaks at 60-70% of MAX RPM. This would put your cruising range RPM somewhere around 2700-3000 RPM. You probably want find much difference in speed and you want thrash your boat and drive gear.
The Volvo homepage - www.penta.volvo.se - shows the RPM range for the TAMD41P ( turbocharged ) to be 188HP @ 3700-3900RPM. This is MAX RPM and for pleasure craft rating should only be used for very short periods of time. If you look at this same engine rated for commercial use, you will see that the MAX RPM is 3200. The commercially rated engine can run at this RPM for long periods of time with no ill affect, but again there is a time limitation on how long - I'm guessing about 6 hours. Again, check with your Volvo marine dealer giving him your engine, prop, boat ( hull shape, displacement, etc. ) specs and he can probably advise you on what will be your best cruisong RPM and also the duration you should use MAX RPM.
Hope this helps.
Jim Jones <jjones@intergate.com>
tonyraymond@digital.com
If you don't have a data sheet for the TAMD41, you need to get one from your Volvo marine dealer. Take a look at the speed/power curves for your engine. The main curve you are interested in is the torque curve. It will be a "hill shaped" curve and you want to set your cruising RPM at just after the peak. This will give the best fuel and least stress on the engine. This curve will also be affected by your choice of prop ( diameter and pitch ). For most of the diesel pleasure craft engines I've looked at, the torque curve peaks at 60-70% of MAX RPM. This would put your cruising range RPM somewhere around 2700-3000 RPM. You probably want find much difference in speed and you want thrash your boat and drive gear.
The Volvo homepage - www.penta.volvo.se - shows the RPM range for the TAMD41P ( turbocharged ) to be 188HP @ 3700-3900RPM. This is MAX RPM and for pleasure craft rating should only be used for very short periods of time. If you look at this same engine rated for commercial use, you will see that the MAX RPM is 3200. The commercially rated engine can run at this RPM for long periods of time with no ill affect, but again there is a time limitation on how long - I'm guessing about 6 hours. Again, check with your Volvo marine dealer giving him your engine, prop, boat ( hull shape, displacement, etc. ) specs and he can probably advise you on what will be your best cruisong RPM and also the duration you should use MAX RPM.
Hope this helps.
Jim Jones <jjones@intergate.com>
tonyraymond@digital.com
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Jim Jones
Re: Heat exchanger, Volvo TAMD41
Tony,
Not sure why I stuck your name and e-mail address at the top. Also I posted this to the wrong query - you had two. Sorry, but still hope it helps.
Jim Jones
jjones@intergate.com
Not sure why I stuck your name and e-mail address at the top. Also I posted this to the wrong query - you had two. Sorry, but still hope it helps.
Jim Jones
jjones@intergate.com
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Joe Merenda
Re: Heat exchanger, Volvo TAMD41
Tony,
I have a Cape Dory 30 with twin TAMD41B's. My engines do not normally run hot. However, I have noticed that if the coolant is the least bit low, the operating temperature increases considerably. With my boat, checking the level visually is not always a good indicator as to how much coolant is in the system. I can add coolant and not visually observe any increase in the level. Unfortunately, the only way I have found to insure that I have eneough coolant is to fill to overflow and then run the engine to operating temperature. My engines have an overflow tube which is used to drain the excess coolant off. I don't recall ever running hotter than 190 deg for any rpm(185 being the average)using this method.
One other thought, have you replaced the thermostats? The TAMD41 has two per engine and the kit(876128-0) costs about $30.00.
Good Luck
Joe Merenda
emerenda@nassau.cv.net
I have a Cape Dory 30 with twin TAMD41B's. My engines do not normally run hot. However, I have noticed that if the coolant is the least bit low, the operating temperature increases considerably. With my boat, checking the level visually is not always a good indicator as to how much coolant is in the system. I can add coolant and not visually observe any increase in the level. Unfortunately, the only way I have found to insure that I have eneough coolant is to fill to overflow and then run the engine to operating temperature. My engines have an overflow tube which is used to drain the excess coolant off. I don't recall ever running hotter than 190 deg for any rpm(185 being the average)using this method.
One other thought, have you replaced the thermostats? The TAMD41 has two per engine and the kit(876128-0) costs about $30.00.
Good Luck
Joe Merenda
emerenda@nassau.cv.net