Testing block heater cord

[spidey]

Usually I don't need to plug my vehicle in, heated garage at home. But still, it is an item that you should have working for when you do need it.

I went to test it like I usually do for any vehicle, plug it in, and wait for the hiss.  I will admit I have never tested it since I bought it.  I even have something I found locally that you can plug in between the cord and the extension cord, and will light up each side to prove you have power, and that your block heater is connected.

Well on 5 vehicle in our house, both things don't work like they should.  No hiss, and no connection with the little tool.  Every other car, each one works.

Anyway, reading more, it shows this block heater will not work until it hits -18 degrees.  Now I don't know if that's -18 Celsius or 1- 18 Farenheight.  I live in Canada, and it was bought here, so I assume -18 Celsius.

anyway, how can a person actually test if it works, unless it kicks in at -18?  Is that why I don't hear the hiss in the garage., becaue it wont activate until that temp?

Any help would be appreciated, as I am going to a part of the country where bthe night time lows will be hitting -40 with no wind-chill next month, and I definitely want to make sure this is working

Really though GM, why make something so simple so complicated.  Why not have it, it just works no matter the temp.

 

[buickwagon]

anyway, how can a person actually test if it works, unless it kicks in at -18?  Is that why I don't hear the hiss in the garage., becaue it wont activate until that temp?

I like to test block heaters with an ammeter using a plug-in adapter. However, even that wouldn't show anything if the block heater has such a temperature control. If your block heater plug has the thermostatic control, it will be pretty obvious. The plug has a big wart on the top.

As for the "why", it's not exactly GM's fault. They had to meet the OBDII regulations and stipulations. Apparently a block heater could interfere with the required self-tests and they had to keep it out of action above a certain temperature:

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.

 

[buickwagon]

I plugged mine in last night. At 5 am ambient air temp was -14?C and the ECT was +17?C. It didn't throw any codes.

I got to thinking about this further. I have a Noma brand block heater timer that I normally use, that has a temp sensor set to -10?C. It seems to me that one could cut off the OEM thermostatically controlled plug, replace it with a straight plug and use a similar external temperature control.  That way the block heater could be tested periodically without sticking the car in a freezer.

Looking at the actual requirements, the code sequence isn't supposed to run if the IAT is below -7?, so -10? should be fine. I imagine GM went with -17? just to allow more room for error as the sensors age.

 

[spidey]

I like to test block heaters with an ammeter using a plug-in adapter. However, even that wouldn't show anything if the block heater has such a temperature control. If your block heater plug has the thermostatic control, it will be pretty obvious. The plug has a big wart on the top.

As for the "why", it's not exactly GM's fault. They had to meet the OBDII regulations and stipulations. Apparently a block heater could interfere with the required self-tests and they had to keep it out of action above a certain temperature:

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.

Yes it has that big block after the cord, so it has the sensor.

So basically they took something simple and made it complicated.  Having to have extra equipment to even test it to make sure it works for each winter.  A person shouldnt need an ammeter to test this, go buy something just for this one thing.

And if its an engine coolant heater, how is that different from a regular block heater that keeps the oil/engine warm?

Anyway had to make my trip, and thankfully (if you can say that) it got cold enough here to test it one night on my way home.  I plugged it in before I pulled into the garage and the little plug adapter I have showed red from the block heater side

A few days later I went on my trip, and while cold, it didnt hit the -40 temps, that happened when I got home.  anyway, I did have the truck plugged in, and it was hovering around the -18 to -20 mark at night.  When I went to start my truck after a couple days of not starting it one morning, it definitely didn't start like it was plugged in, and was running a bit rough.  I let it idle for a few minutes while I cleared of snow, etc.

When I went to drive away, it was still idling rough, and then when I went to drive, it threw a Check engine light.  Great, its 6 am, I have a 10 hour drive, Im in the middle of nowhere on the Saturday before Christmas.  Now what.  So I drove slow to say good by to the person I was seeing there, and shut it off. 

Now what, no local mechanics, closet GM dealer is an hour away, etc.

So I got back in, started it up.  Started way better, no rough idle.  Let it sit for a few minutes, than decided to try and drive it again.  No check engine light.  And I dont have my code reader with me.

So I drove, and drove, and drove.  No light ever again, got home, no codes in memory either.  Hasnt happened since.

Im assuming this what you said "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."

Now I have started my vehicle below in very cold weather, but thats when its parked for the day at work, or a few hours at night when out for the evening, not for two days straight in the wind and cold.  So maybe thats why the code and the rough idle.

Even so, didnt make me feel very comfortable on the drive home, being stranded in winter

 

[buickwagon]

Can you check history codes with your reader? It would be interesting to see if the code stored is in any way related to the start up temp or if it's something completely different (eg: TPS).

 

[Bassman Z71]

Yes it has that big block after the cord, so it has the sensor.

So basically they took something simple and made it complicated.  Having to have extra equipment to even test it to make sure it works for each winter.  A person shouldnt need an ammeter to test this, go buy something just for this one thing.

And if its an engine coolant heater, how is that different from a regular block heater that keeps the oil/engine warm?

Anyway had to make my trip, and thankfully (if you can say that) it got cold enough here to test it one night on my way home.  I plugged it in before I pulled into the garage and the little plug adapter I have showed red from the block heater side

A few days later I went on my trip, and while cold, it didnt hit the -40 temps, that happened when I got home.  anyway, I did have the truck plugged in, and it was hovering around the -18 to -20 mark at night.  When I went to start my truck after a couple days of not starting it one morning, it definitely didn't start like it was plugged in, and was running a bit rough.  I let it idle for a few minutes while I cleared of snow, etc.

When I went to drive away, it was still idling rough, and then when I went to drive, it threw a Check engine light.  Great, its 6 am, I have a 10 hour drive, Im in the middle of nowhere on the Saturday before Christmas.  Now what.  So I drove slow to say good by to the person I was seeing there, and shut it off. 

Now what, no local mechanics, closet GM dealer is an hour away, etc.

So I got back in, started it up.  Started way better, no rough idle.  Let it sit for a few minutes, than decided to try and drive it again.  No check engine light.  And I dont have my code reader with me.

So I drove, and drove, and drove.  No light ever again, got home, no codes in memory either.  Hasnt happened since.

Im assuming this what you said "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."

Now I have started my vehicle below in very cold weather, but thats when its parked for the day at work, or a few hours at night when out for the evening, not for two days straight in the wind and cold.  So maybe thats why the code and the rough idle.

Even so, didnt make me feel very comfortable on the drive home, being stranded in winter

I got tired of the -18 degree thing. I bought an Oil Pan heater for $70 bucks (Parts source / Canadian Tire), slapped it on the oil pan with the self adhesive and nice warm oil in the morning and smoother engine start (no chatter). 

 

[Gagemf]

What oil pan heater and do you plug the block heater also?