beasleyiv

I guess what I'll do is pull the cord and check with a meter. If I don't get continuity I'll cut the end off and check the bare wire.

Oh, and by the way, my new block heater doesn't work, at least not in the balmy 25 degrees here.

Check this out guys: Techlink December '04 Engine Coolant Heater and P0116 Owners of some 2005 V8 trucks and V6 cars with the factory optional engine coolant heater (also known as a block heater) may comment that the heater does not work unless the air temperature is very low. This is normal operation, intended to avoid setting a DTC P0116. TIP: This operation is described in the owner’s manual. The power cord has a built-in thermostat that allows operation only if the temperature of the surrounding air is at or below 0°F (-17°C). Also, the heating element has a low power rating to limit the amount of heat in generates. TIP: The air temperature thermostat is part of the cord set, not the heater. A DTC P0116 may set if the vehicle has an aftermarket engine block heater installed that is more powerful than the factory-installed one and/or that is not equipped with the thermostatic AC power cord. Explanation of Rationality Check The P0116 diagnostic (engine coolant temperature sensor rationality check) can fail if the indicated coolant temperature is too high at engine startup, after an extended time sitting without the engine running. After a vehicle has been parked for a number of hours, the engine coolant temperature is typically very close to ambient air temperature. This is the definition of a cold start. After startup, OBD regulations require that the PCM look at the rate at which the coolant temperature sensor heats up, from a certain starting point. If the coolant temperature sensor does not heat up according to expectations, a DTC P0116 will set. The new heater described above has been designed to keep the coolant temperature sensor operation outside the range that would cause a DTC to set. - Thanks to Jack Woodward and Guy Winohradsky

Arcticj, I think your theories are probably accurate. What about buying the same heater I did, just for the cord, and trying that? I know, expensive cord, but it might be worth the peace of mind to solve the mystery.

I don't see a part number, but here is the end of the cord for reference. I don't see the buldge that everyone is talking about.

Ok, I just couldn't wait any more. I bought one. The one I got doesn't have any bulge on the plug end. Looks like a standard three prong plug. I won't know if there is a stat until I get it installed, but I can hope.

Hmm, thanks for checking. Are guys just cutting off the end and wiring in a replacement plug? Is it possible for you or someone to call the techline and get a confirmation?

Hey, I thought of a couple more questions. First, how much coolant am I going to lose? Second, I've seen the recent posts about these heaters possibly having a thermostat that keeps them from working above 0 degrees C. Is this true?

Sweet. Thanks for all the help. I'll be doing this in a couple of weeks.

Oh, so I'm not taking out a freeze plug? This is what's going in: That looks to be the standard freeze plug size. If this is just unscrewing a plug and putting this in that seems much easier than yanking out a freeze plug. My only other experience with doing a block heater was on a 1979 Toronado 350 diesel conversion motor.

Thanks for the insight. Which plug do you take out? The rear most? Does anything else have to come off to reach up in there?

I have found 12497459 as the possible part number for an engine block heater. The description is: 5.3 liter MFI 8 cyl engine, 6.0 liter MFI, HO, V8, iron engine (6.0N), 4.8 liter MFI 8 cyl engine, 8.1 liter MFI 8 cyl engine (496 CID), 5.3 liter flexible fuel (gas/alc) 8 cyl engine with MFI. Notes: t/w gasket 12560438 for vehicles w/LQ4 or LQ9) Can you verify this would work on my 2003 5.3L 1500 4x4? Will I need the gasket? Thanks!!