MD6a Operating Temperature

tiempo2010 · Jul 1, 2013

Is it a raw water cooled engine? If it is the thermostat should be changed
to 140. If a closed system keep the one you have.

stevebirch2002 · Jul 1, 2013

Hi Bob

Dont worry about the temp until it gets over 90 degrees C

Usual problem is overheating and in that case I take the thermostat out completely

Cheers

Steve BFrom: whiskerpole
Sent: Monday, July 01, 2013 5:04 PM
To: AlbinVega@yahoogroups.com
Subject: [AlbinVega] MD6a Operating Temperature
My Vega MD6a Running temperature is about 70 C (160 F). This seems inline with the MD6a manual, but I've read the raw water cooled diesels should run at 60 C (140 F).

The boat is in salt water now, but was previously used in fresh water.

Should I change the thermostat, or is all OK?

Bob Fuchs
V 2194
Solentium

tiempo2010 · Jul 1, 2013

If a thermostat is used in salt water that is too hot - 160 F for example -
salt deposits will develop rapidly in a raw water cooled engine. That is
why salt water cooled engines use 140 F thermostats.

dougpol1 · Jul 1, 2013

My Md6b runs right at 140 F. The last owner had a 160 deg thermostat in
the engine and she has a lot of salt in her. I hook up the fresh water
hase to the engine every chance I get to run water through her. Mine
now has no thermostate and runs 140 anyway I guess there just happens to
be enough salt in her to cause that. She will be cooked out this fall
when my Mechanic rebuilds her if we decide it is needed. Any body know
how to get the salt out without cooking her. Doug

tiempo2010 · Jul 1, 2013

Doug

You use Ridlime, run the solution into the block and let it sit for a while
and then flush. Specially formulated to get salt out of engine cooling
passages. RID LIME RIDLIME MARINE

vegatern · Jul 1, 2013

Although I can't put the boat in gear I run the engine periodically to keep it lubricated. A while ago the temp gage pegged so I shut down. I couldn't fine anything wrong and the engine did not feel hot so the next time out I ran it again . . . until it pegged again. Checked and nobody is living in the intake so I pulled the thermostat. The gage is still pegged so it must be the gage but, if the engine was actually hot would not the exhaust water feel hot? (It is cool). MD7A

Craig

pjacobs55 · Jul 2, 2013

Do beware of not trusting the gauge.

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From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On Behalf
Of Craig
Sent: Tuesday, July 02, 2013 1:19 AM
To: AlbinVega@yahoogroups.com
Subject: [AlbinVega] Re: MD6a Operating Temperature

Although I can't put the boat in gear I run the engine periodically to keep
it lubricated. A while ago the temp gage pegged so I shut down. I couldn't
fine anything wrong and the engine did not feel hot so the next time out I
ran it again . . . until it pegged again. Checked and nobody is living in
the intake so I pulled the thermostat. The gage is still pegged so it must
be the gage but, if the engine was actually hot would not the exhaust water
feel hot? (It is cool). MD7A

Craig

tiempo2010 · Jul 6, 2013

Yes, you are correct. Running a raw water cooled engine in salt water with
a higher than 140 degree thermostat will let salt deposits build up in the
passages in the block.

lewills30 · Jul 20, 2013

Closed coolant system

Can a closed coolant system be installed and use the salt water to cool the closed system. Are they called heat exchanges? The coolant is in the tank and the salt water flows inside a or through the sealed double walled tank?

Sent from Windows Mail

From: Brian Stannard
Sent: ?Saturday?, ?July? ?6?, ?2013 ?8?:?43? ?PM
To: AlbinVega@yahoogroups.com

Yes, you are correct. Running a raw water cooled engine in salt water with
a higher than 140 degree thermostat will let salt deposits build up in the
passages in the block.

dougpol1 · Jul 21, 2013

Yes you can convert a volvo to a fresh water system. I don't see much advantage in it unless you will be using the boat in very cold weather where the engine will have to be winterized every time you use it in cold weather. The salt water will not hurt the engine block as the castings have a lot of nickle in them and will last many years after the engine is worn out. DougOn Sun, 21 Jul 2013 04:41:20 +0000
lewills30@... wrote:

dougpol1 · Jul 21, 2013

I had intended to also mention that the freshwater cooled system can be more efficient as instead of running at 140 degrees to not make salt crystals It can run at 180 deg. or more. The the one and two cylinder Volvo engines were the state of the technology back in the 1920's when they were designed. The engines could run at 2400 rpms at a time when many marine engines ran at 700 rpms and had no oil filled crankcase but instead had oil cups that you had to fill every few hours. So a freshwater cooling system would be an advantage from an efficiency advantage but not likely one of longevity of the engine. Doug

On Sun, 21 Jul 2013 04:41:20 +0000
lewills30@... wrote:

MD6a Operating Temperature

Whiskerpole

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Whiskerpole

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tiempo2010

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stevebirch2002

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tiempo2010

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dougpol1

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tiempo2010

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vegatern

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pjacobs55

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tiempo2010

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lewills30

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dougpol1

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dougpol1

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