I buy a lot of parts from Walt and rockauto, compare prices. The two securing nuts are 15 mm, I don't know the terminal ones, easy replacement. The mains plug-in heater is a block heater element, low down on the drivers side of the engine, half way along, it heats the water in the engine. I have never had a GP relay break, and the retaining threads on the suburban one, must be nearly worn out from removing it so many times to remove the head. Someone else had the breaker pop from the block heater, and I think it was because of salt on the heater. It is difficult to remove, even with the engine out of the vehicle. If you are thinking about replacing it, let me know, I will send photos of one removed, and how to release it, I deleted it on the new engine, because the temperature here does not drop below 60 deg F, I also only have one battery in each vehicle.
Last edited by grancito; 03-19-2022 at 07:12 PM.
Grant H.
1995 6.5 turbo GMC K2500 extra cab 4x4 pickup, PMD under bumper, mechanical wastegate, 228,000 miles, rebuilt engine, 4.10 diff, 16 mpg
1994 6.5 turbo GMC K2500 4x4 suburban #9 resistor, PMD in the bumper, mechanical waste gate, 226,000 miles, new engine, 0 miles. 3.73 diff, 16 mpg
1982 4x4 shortbed 6.2 Chev 260,000 miles untouched motor 17 MPG 4.27 diff. Best thing I ever owned, since 1992.