5.3L engine block heater

GM-Tech · December 16, 2005

again, how can there not be someone at GM with the answer as to why this is...And from the posts, in addition to my own experiences, why when you as several people, who are supposed to be professionals in this business, do you get several different answers to the same question?

Oh, there's someone at GM that knows the answer. It's just finding him or her.

As for getting different answers based on the person contacted... is it really any different anywhere else? I don't think so. I've called on various topics from insurance problems (darn hurricanes) to tech licensing in Dade county. I get a different answer every time I've called!

That's not to say that it shouldn't be that way.

beasleyiv · December 16, 2005

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.

Edited December 16, 2005 by beasleyiv

dewfpo · December 16, 2005

Just a thought from another forum...the combination of metal (block heater) and aluminum (block) causes corrosion when electicity is introduced via the heater...therefore, GM lowered the operable temperature thus greatly reducing the use of the heater and as a result, greatly reduced the potential problems from the corrosion issue...

<{POST_SNAPBACK}>

The block and heads on my 8.1L are still both iron, yet the d**n thermostat in the plug. So there goes your therory......

DEWFPO

ArcticJ · December 17, 2005

The block and heads on my 8.1L are still both iron, yet the d**n thermostat in the plug. So there goes your therory......

DEWFPO

<{POST_SNAPBACK}>

Dewfpo- Unless the factory is just installing one block heater instead of block specific heaters...

Beasley- I could do that, but if operating your heater in my block does not harm anything...I would probably just lop off the plug on my factory heaters and install a heavy one from a hardware store...It would probably work, but again, I'm concerned about harming something and thus the reasoning behind GM's wonderful decision to outfit these trucks as such...

GM TECH- you are absolutely right...this industry is no different than any other...quality answers are tuff to come by whether you're buying carpet or a light switch...it's about finding the right people at the right time...I certainly agree, I guess I'm just looking too hard for that one person who has some insight as to why this is...

Does anyone have access to a parts sheet to determine if the p/n is different for heaters from say 2002 and 2005 or 2006? Again...if I go in to buy one from the dealer, as in Beasleys case, what numbers are they finding to order the part? Are there notes or *'s citing that certain yeared vehicles must have the thermo equipped plug? If not, what would stop a part guy from handing out a clean plug to an 06 owner?...would not make it right and certainly a good arguement when something goes wrong..."not my fault...this is the heater you guys sold me," but if there are no notes for the differing heaters, this has to happening somewhere...

MS3DALE · December 19, 2005

Arctic...Funny you should ask about part numbers,They changed heater & cord part numbers in the mid-'05 model year,The first design is a 3-pin brass colored connector and the second design is a 2-pin silver colored connector,Now the connector they are talking about is where the cord plugs into the heater itself.

I have the first design since mine is an '04,'05's can have either.And of course '06's have the second design.

To be honest with you I'm still trying to figure out if mines working above 0 degrees F,And still trying to find an answer why GM put a thermostat in the cords.

beasleyiv · December 19, 2005

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

beasleyiv · December 19, 2005

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

Trouttrooper · December 19, 2005

I double checked my owners manual again and all it says it that the heater will only work below 0F, and that above 32F you don't need to use a heater. They fail to explain what should happen BETWEEN 0 and 32.

There's no explanation in the book about setting off a DTC P0166.

The way that thing is described, sounds like they also put in a wimpy heater compared to previous years. Whoever designed this must not know what snow is.

Anyway, thanks for giving us this info. Makes me feel better now that I can replace the tumor plug with a normal one and not seriously damage anything.

beasleyiv · December 19, 2005

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.

ArcticJ · December 19, 2005

YOU GUYS ARE UNBELIEVABLE...BEASLEY AND EVERYONE ELSE...THANK YOU FOR FINDING AN ANSWER...now the next set of questions

Im not a tech or anything more than a garage mechanic...what I get out of that is the OBD (On Board Diag.?) will generate a DTC (Diag. Trouble Code?) #P0116 because the PCM (?) does not recognize or like the high starting temp or the coolant according to the coolant temperature sensor or the slow or out of ordinary warm up of the coolant because it is already warm...

I can understand that, I think but why didnt GM, when faced with this situation, modify the PCM and it's dianostic procedures (probably a bigger deal than I know) or if inserting a thermostat, set the useable temp around 15 degrees?

I used the heater on my 02 burb without problems or codes...perhaps someone (or alot of them) decided 40 degrees was too cold and plugged in the truck thus generating this DTC thing. Is there really a big difference if its 0 degrees or 10 degrees outside???

As for the plug cutting group...would this void out a warranty if a problem would arise?

And with that, what problems could possibly arise if the heater was used with a new plug in temps of 15 degrees or colder?

For those who have already cut...are you getting any DTC's yet? What kind of temps have you used it in and how many times?

And ultimately, any special parameters for the new plug other than grounded?

THANKS AGAIN...I CAN'T BELIEVE THE RESOLVE OF THIS GROUP...YOUR ALL AWESOME....

ArcticJ · December 19, 2005

One more thought...does the check engine light come on or is the code just get stored away not to bother you until you bring your truck in?

GM TECH...what do you think about all of this?

MS3DALE?

check this link out (If I didn't post it right, just copy and paste it in the address bar...does this help you tech guys out?

[url=http://gearchatter.com/viewpost14669.php?sid=6e62b08960a65c17cee608d37bd822b1

Edited December 19, 2005 by ArcticJ

GM-Tech · December 20, 2005

why didnt GM, when faced with this situation, modify the PCM and it's dianostic procedures (probably a bigger deal than I know) or if inserting a thermostat, set the useable temp around 15 degrees?

Yeah, it is a bigger deal than you realize. This is not GM's decision. They have to meet certain standards that define what tests are run, when, and what the results must be to be in compliance. They can't just tweak things to suit their (or your) needs.

As for your question as to whether or not the light will come on.... yes, after the second consecutive failure. Here's the full details on the criteria that must be met for DTC P0116 to run and what happens if it fails. This test appears to be able to detect if a block heater is in use, in which case the test aborts, but perhaps under some conditions, it may fail the test anyway.

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Conditions for Running the DTC

• The ignition is ON.

• DTCs P0112, P0113, P0116, P0117, P0118, P0128, P0502, P0503 are not set.

• The start-up IAT is more than -7°C (+20°F).

• The vehicle has a minimum ignition OFF time of 10 hours.

• DTC P0116 runs once per drive cycle when the above conditions are met.

Conditions for Setting the DTC

• The start-up ECT is more than the start-up IAT by 100°C (180°F). OR

• The start-up ECT is more than the start-up IAT by 15°C (27°F), then the vehicle must be driven for more than 400 seconds over 24 km/h (15 mph). If the IAT sensor temperature decreases more than 8°C (14°F), a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, a block heater was not detected and DTC P0116 sets.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• Clear the MIL and the DTC with a scan tool.

ArcticJ · December 20, 2005

why didnt GM, when faced with this situation, modify the PCM and it's dianostic procedures (probably a bigger deal than I know) or if inserting a thermostat, set the useable temp around 15 degrees?

Yeah, it is a bigger deal than you realize. This is not GM's decision. They have to meet certain standards that define what tests are run, when, and what the results must be to be in compliance. They can't just tweak things to suit their (or your) needs.

As for your question as to whether or not the light will come on.... yes, after the second consecutive failure. Here's the full details on the criteria that must be met for DTC P0116 to run and what happens if it fails. This test appears to be able to detect if a block heater is in use, in which case the test aborts, but perhaps under some conditions, it may fail the test anyway.

---------

Conditions for Running the DTC

• The ignition is ON.

• DTCs P0112, P0113, P0116, P0117, P0118, P0128, P0502, P0503 are not set.

• The start-up IAT is more than -7°C (+20°F).

• The vehicle has a minimum ignition OFF time of 10 hours.

• DTC P0116 runs once per drive cycle when the above conditions are met.

Conditions for Setting the DTC

• The start-up ECT is more than the start-up IAT by 100°C (180°F). OR

• The start-up ECT is more than the start-up IAT by 15°C (27°F), then the vehicle must be driven for more than 400 seconds over 24 km/h (15 mph). If the IAT sensor temperature decreases more than 8°C (14°F), a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, a block heater was not detected and DTC P0116 sets.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• Clear the MIL and the DTC with a scan tool.

<{POST_SNAPBACK}>

Ok..I see the criteria for the test...what if the engine was started once every 9 1/2 hours, or before the 10 hour mark,...not meeting the 10 hour criteria of a minimum of 10 hour off time. Would that avoid the diagnostic and thus the potential for the trouble code?

And/or do you think this trouble code is a result of the heater being used when the temps are too high...above 30...and since it was generating this code, GM installed the thermostat to eliminate the grief?

And unofficially, is it a big deal to circumvent the plug if it was only used in <15 degrees?

dewfpo · December 24, 2005

Does anyone know what the wattage rating is of this 'new' lower powered single block heater on thesre newer trucks?

My 85 Ford has two factory 750 watt heaters, one on each side of the 351 engine. It's nice and toasty on startup no matter how cold when the block heaters are plugged in.

DEWFPO.