3GM30F temperature gauge

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May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
My 3GM does not have a temperature gauge. I bought a VDO gauge with the metric to SAE brass adapter sleeve for the sender unit but I do not see a plug in this engine I could use. It looks like I will have to add a T to the original sender or maybe T into the line going to the hot water tank.
I'm wondering what others have done. Anyone with experience doing this have a good solution ?

thanks Bob
 
Dec 19, 2006
5,733
Hunter 36 Punta Gorda
Tee

Don't tee in to the sender unit,many years I did that and about a year after it was working fine the brass fitting snapped off and lucky no damage.
I have photo which I need to find to tee into the hose that comes out of the engine cooling.
Nick
 
Jun 7, 2007
515
Hunter 320 Williamsburg
Alternative

Overheating doesn't just happen, usually you can sense it by sound and performance. Buy a $30 heat gun and target the hot spots in the center of the engine. Works for me on my 18hp Yanmar (320H). Get a refund on your temp gauge.
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
In a post back in December, Joker460 showed this for installing the sender in the hot water line to the water heater..
https://www.pegasusautoracing.com/p...//www.pegasusautoracing.com/keywordsearch.asp
This location will measure the temperature accurately and will avoid the innacuracy and breakage you'll have if you try to tee the alarm sensor and temp sender together..
Claude, thanks so much, exactly what I needed to know, I will order one and install it when I flush the cooling system and replace all my hoses.

Nick thanks for sharing the experience, I don't want to go down that road.

Deadline, I have an infrared thermometer and have used it on the engine, all seems fine at this point. If I was just sailing in and out of club I would not bother with this mod. We do have to deal with strong currents at times, waiting for a bridge opening, coming in an inlet or through a cut, knowing the engine temp. is fine will lower my stress level a bit, so well worth the little time and money expended.

thanks, Bob
 
Jan 22, 2008
1,591
Hunter 34 Alameda CA
Bob,

Just in case you don't have too much information:) here is where I mounted mine. There was actually an extra port on the thermostat housing that I used. Some have it and some don't. You can see in the photo both the analog sender on top (with adapter bushing installed) and the original buzzer sender just below. Having that monitoring capability has been great in diagnosing plugged strainers, mixing elbows and bad thermostats over the years.

Allan
 

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May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
Bob,

Just in case you don't have too much information:) here is where I mounted mine. There was actually an extra port on the thermostat housing that I used. Some have it and some don't. You can see in the photo both the analog sender on top (with adapter bushing installed) and the original buzzer sender just below. Having that monitoring capability has been great in diagnosing plugged strainers, mixing elbows and bad thermostats over the years.

Allan
Allan, thanks for taking the time, I don't think I can ever have too much information ! I do not have a port like that on my thermostat housing. So I guess I am going to go with the water heater line.

I did look at Joker460 posting Claude referenced on this. He says the temperature sender was installed in the water heater return line, but I think the picture shows it in the supply line, his picture is below.

If it were installed in the return line then you would have to add the temperature drop of the coolant as it went through the water heater and that changes with temperature of the hot water !

regards, Bob
 

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Nov 6, 2006
9,225
Hunter 34 Mandeville Louisiana
You are right, Bob.. That's why I noted: sender in the line to the water heater.. Joker 460 did say from .. but he has the sender in the line to .. which is the correct placement. I am considering doing this as well.. let us know how it works out !
 
Jun 4, 2004
812
Hunter 340 Forked River, NJ
Digital gauge with alarm

Several years ago I installed a CruzPro T30 digital temperature gauge with alarm on my 2000 H340 with the Yanmar 3GM30F engine. This way I have a digital temperature gauge with the benefits of an adjustable over-temp alarm and with only one sensor on the engine. I replaced the original Yanmar temperature sender with a Telflex 3/8” sensor. The alarm was set at 190F. I used the original blue/white wire from the old sensor to the new gauge in the pedestal. The ground for the gauge was tapped into a common ground wire on the fuel gauge and the Positive wire was tapped into the Positive lead on the ignition switch. The gauge workes great and was calibrated for the Telflex sensor (U-4). I have used it for several years now and it gives me good continuous reading of the engine temperature. http://www.cruzpro.com/t30.html.
 
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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Perhaps putting the inline close to the water heater might simplify installation in SOME cases- without much of a temperature drop compared to the engine end of the same hose?
 
Jan 22, 2008
1,591
Hunter 34 Alameda CA
I guess I was lucky to have that extra port on my thermostat housing for my extra sender. Rather than Tee-ing off the current temperature port, how about a Tee in place of the connector to the heater hose? Then the sender can be mounted there and the hose continues on to the heater. Just a thought and it would be cheaper than the in-line solution presented.
 

galynd

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Nov 1, 2009
170
Beneteau 36cc port arthur, tx
I T'd mine on the hose to the hot water heater just off the engine. It works well. same engine.
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
up date

I ordered the in-line temperature sleeve from Pegasus.

I found that the brass sender almost completely blocks the brass sleeve when it is screwed in. I expected the brass would have a bit of a bulge in it but it is smaller ID than the 5/8" hose ID. So when the 3/8" sender goes right through the center it reduces the area of the pipe by 80 or 90% ! I guess others have used it and it works but I don't think I will. I have a metal lathe at home and may make one up next summer and finish this project when I come back south next winter.

In desperation I went to Home Depot and looked at a 1/2" brass plumbing T with two 5/8" nipples. The problem is a 1/2" to 1/8" brass adapter is so long it covers the whole sender unit in brass and also it does not extend down into the middle of the T.

Bob
 
Apr 27, 2010
931
Beneteau 352 Hull #276 Ontario
Bob 04 H260

What I did (and forgot to mention, sorry), I used a 1/4 npt tap to enlarge the existing sender hole. Then used a brass reducer between the sleeve and temp sender. That gives the clearance you're looking for.

You can see it in the previous picture. I have blown it up and attached.
 

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May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
Joker, thanks for the come back on that.

After I posted that I went to Home Depot got the brass T, two brass nipples for 5/8" hose, and 1/2" to 1/8" pipe threaded plug. Then stopped at Harbor Freight to buy a tap & die set on sale, it had the 1/8" pipe thread tap. Then back to the boat and assembled the parts. Then hacksawed off the end of the 1/2" to 1/8" plug so it was flush with the T. I re-tapped the 1/8 thread deeper into the plug so the temperature sender extends down into the middle of the T. Then drilled and tapped a small hole for a 10-32 brass bolt for the ground wire. It all went on the engine fine.

I've now replaced all the engine hoses and clamps. I used the new to me ABA hose clamps (http://www.bakerprecision.com/hoseclmp.htm) I really like these hose clamps.

Now waiting for the new Lifeseal raw water pump plate and I can start the engine and test it all out.

Bob
 
Apr 27, 2010
931
Beneteau 352 Hull #276 Ontario
That will work. Sorry again for forgetting the additional mod I made. You may be able to return the Pegasus part since you didn't use it. It's worth a try.
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
Joker no problem, if I don't use it for something one of my friends will mod it for use on their vehicle. Not a concern at all.
thanks, Bob
 
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