temp sending units - 1988 mid cabin

BobCT · Post by **BobCT** » Wed Dec 09, 2009 11:34 am

Have any of you guys replaced the coolant temp sending units?

Both my gauges are off (one by 20 degrees) and it's driving me crazy. I cleaned up the connections on both engines but haven't looked behind at the actual gauges yet.

Does anyone know the correct part # for the sending units? Would they be the most likely suspects?

I also have oil pressure gauges that work but bounce around. I was thinking of doing the same for these.

Bob

S.A.M. · Post by **S.A.M.** » Wed Dec 09, 2009 3:11 pm

Bob,

Through the years, what I've found, is in older boats the wiring begins to lose it's impedance, which causes the gauges to read off and work sporadically.

Run jumper wires to your gauges to check them before you replace them.

prowlersfish · Post by **prowlersfish** » Wed Dec 09, 2009 6:51 pm

Check you grounds

reelfishin · Post by **reelfishin** » Wed Dec 09, 2009 8:17 pm

I would definately be checking all my connections before I would condemn the guage. Grounds as Prowlerfish said can definately cause those kind of problems.

BobCT · Post by **BobCT** » Thu Dec 10, 2009 8:28 am

I was thinking more along the lines of bad sending unit vs. the gauges being bad. I think they work, they're just not accurate.

Sounds like a wiring/connection issue is more likely from what you guys are saying.

Bob

koviak · Post by **koviak** » Thu Dec 10, 2009 5:00 pm

I have replaced both of mine this past year with crusader parts. Sending units were bad (high readings), will try and find the part number for you.
1989 engines,they don't last forever!

BobCT · Post by **BobCT** » Thu Dec 10, 2009 8:43 pm

do you have a single helm and/or mid cabin also?

I know that makes a difference....

I checked the wiring behind the gauges and it cleaned up fine. Pretty sure new senders will do the trick.

thanks,
Bob

koviak · Post by **koviak** » Sat Dec 12, 2009 7:19 am

I have a 10 meter mid-cabin (1989)

prowlersfish · Post by **prowlersfish** » Sat Dec 12, 2009 9:10 am

The fact there both off by 20 derg. make me think its a ground issue as thats something they share on both gages. the power for each one comes from different sources . also the senders may be they wrong ones for your gages ( need to match) How do to know they are 20 Deg, off ?

BobCT · Post by **BobCT** » Sat Dec 12, 2009 9:55 am

the IR gun. The other is off about 5 degrees doing the same test. I can live with off 5 but not 20. Nothing has been done to the boat so I'm positive the sending units are original.

I'd rather not do a "conversion" everytime I look at the gauge....

Bob

prowlersfish · Post by **prowlersfish** » Sat Dec 12, 2009 10:06 am

a IR will normally read lower then the gage as your reading the outside of the engine as the heat bleeds off some . I find about 10 degrees difference ., are you checking both engines in the same spots and near the senders ? there can a temp difference on each side of the same engine .

Of 9 out 10 gage issues I have fixed have been ground problems

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temp sending units - 1988 mid cabin

temp sending units - 1988 mid cabin

I guess I'll clean up the wiring behind the instr panel 1st

that would be great, I haven't had any luck otherwise.

Paul, one is off approx 20 degrees according to...