COOLANT and TEMPERATURE SENDER (Part 2 of 2)
I tested the sender and found that it was 2.4 kohms cold and around 400 ohms at 212 F. With the sender connected to the gauge wire and grounded, I stuck it in a soldering iron for toomuch heat and watched the gauge run full range (stop, don’t peg it, dude) so I knew the gauge and electrical were working. I found some info on an appropriate sender at
http://gmcmotorhome.info/engine.html#sender. The NAPA Echlin site catalog has the tech specs on resistance vs. temp but it's a huge .pdl and doesn't always DL. I bought a NAPA Echlin TS6469, the cheapest one I found on eBay. The existing sender was mounted in a 3/8 NPT hole in the cylinder head. The TS6469 is ½ NPT, so I installed it in the intake manifold. I didn’t have enough clearance at the thermostat housing so I installed it on the opposite side, abandoning my heater hose connection for the time being. The wrap on the OG sender wire is thrashed but I secured the wire better than it was. I get a decent indication on the gauge now, a little below halfway when fully warmed up. I’ve driven it a couple of times since changing the sender. The gauge hovers around where you see it in the pic below so I’m good with it.
The total below surprised me a little but at least I didn’t have to buy hoses or a water pump, and the radiator looks to be in good shape.
Coolant (2 gals)….…$ 23.90
Thermostat………….....13.04
Radiator cap………….....4.34
Fan clutch………........35.88
Temperature sender..10.45
3/8 NPT plug………....…3.03
½ NPT plug…………......3.80
Total……......……….$.94.44
(P.S. I took the day off from stressful truck repair duty and vented here all day instead)