Temp Gauge

[2004SSI180]

Just wondering if anyone has any idea why the temp gauge is not working. Any tests i can do to find out. The boat is a 2004 ssi180 chaparral 3.0l volvo penta

Thanks,
mike

 

[thannah84]

Re: Temp Gauge

Take the lead (Wire) off of the temp sending unit and ground it to the engine block. The gauge should go all the way to Hot. If this happens, the gauge is working fine..If not, then it's bad.

 

[HT32BSX115]

Re: Temp Gauge

Howdy,

Your temp gage is a fairly simple device.

Think of it as an ammeter (it actually IS)

It measures the current passing thru the sender (which is grounded to the block).

The sender is a variable resistor that changes resistance INVERSELY with temp.......I.E. temp goes UP, resistance goes down. (when the resistance goes DOWN, the gage indicates MORE current and goes higher.)

If you (like suggested above) short out the sender with a piece of wire to anywhere on the block. (with the gage still connected) the gage should go to full scale.

If it doesn't, the wire from the gage to the sender is "open" or broken.

OR, the 12v power to the gage is disconnected, or a fuse is "open" (blown)

OR, the gage is defective.


Your oil pressure gage works (and is wired) the same way.


Cheers,


Rick

 

[2004SSI180]

Re: Temp Gauge

Thanks Rick I'll try all that and see if it works or not.

Mike

 

[jam1ej20]

Re: Temp Gauge

Has the temp gauge never worked? Just stopped working recently? Stopped working after you performed some maintenance? My gauge wasn't working and I found that my thermostat housing wasn't grounding properly which doesn't allow the sender to work properly. The trouble shooting portion of the manual steps you through how to test the gauge and sender separately.

 

[HT32BSX115]

Re: Temp Gauge

Has the temp gauge never worked? Just stopped working recently? Stopped working after you performed some maintenance? My gauge wasn't working and I found that my thermostat housing wasn't grounding properly which doesn't allow the sender to work properly. The trouble shooting portion of the manual steps you through how to test the gauge and sender separately.

damn! Left that one out!!! Thanks to jam1ej20


If the gage goes full scale when you short out the sender, also try connecting your ground-test wire to the part of the sender that is (or should be) grounded thru the housing (the engine will have to be warm enough so the gage will indicate *some* temp if it's going to work though.........

If the above has happened, it'll start working when you ground the housing or "ground" the sender.


As an aside, Mercury puts little brass rivets in some of their t-stat housing gaskets to help keep the housing grounded....

Most or all aftermarket gaskets do not have the rivets.... so if you get a little corrosion on the bolts you lose the ground path for the sender-gage.

 

[2004SSI180]

Re: Temp Gauge

yes the gauge worked before no problem. I havent had a chance to test it yet.

 

[ken_23434]

Re: Temp Gauge

The Instrumentation section of the Mercruiser Service manuals have a section on testing all the guages. There is a chart in there that shows the resistance value of the sending unit for 3 or 4 different temperatures.

The advice given above though is part of what is in the manual. A high resistance should read a low temp, and a low resistance will read a high temperature.

I just had to replace my sending unit. As soon as the key was taken to the <RUN> position, my temp guage would jump to about 200 degrees. After running a while, the guage would end up dropping to 160 and appear to work correctly. With a cold engine, I know the 200 reading was bad. I am not sure what about the sensor caused it to read correctly at times and bad at other times. Luckily, an easy fix, though.

 

[2004SSI180]

Re: Temp Gauge

It ended up that the gauge was bad. I ordered a new one it'll be here tuesday from west marine $29.99. It is a teleflex gauge. Come to find out that teleflex is not making gauges no more I'm lucky i found one that matches.

Thanks all for your help.

Mike

 

[Timbolex]

I see this post was from Years ago, but if I can stir it up again, just bought a 2003 chaperral 230ssi, temp was reading high...very high, changed tstat and impeller and again reading just above 210ish, I used an IR thermometer and the heads read around 175° so I did the unthinkable and ran it 40 minutes straight at 35/40 mph engine ran perfect, no smoke and oil looked great, I'm guessing it's the guage?