Engine Block Heater

bob · January 29, 2003

We're having this discusion on a lawn forum. A fellow there said his Chevy dealer said not to plug the engine block heater in, until it hits -30 degrees for a few days. I told him that I plug mine in when it gets in the low 20's. He says that it will heat the fuel up and cause the SES light to come on. He also said ,that his dealer says that GM is leaving engine block heaters out of the new Duramax. None of this sounds right to me.

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CMNTMXR81 · January 29, 2003

Sorry! That is some of the most absurd B.S. I've ever heard! Fuel heating? How? It heats the engine block therefore keeping the oil viscous, NOT the fuel lines! So when it's 100 degrees outside, should I expect an SES light cause my fuel gets warm?

I've always plugged mine in when it reaches around 0 degrees. A common indicator is when I notice the engine is audibly slower to turn over because the oil is thick as molasses due to the cold.

Perhaps they are leaving them out of D-Max's to actually help COOL the engine more efficiently because no blanket is around it or the oil pan to block free flowing air to it.

hdmax · January 29, 2003

As stated earier; That is total BS. I plug my in every evening when I get home (unless I know I will not be driving it the next day) As long as the predicted low temperature is to be in the 30`s or less. And I have never had any SES codes or any codes for that matter.

When I get in to go, the heater is blowing warm air, the oil pressure is in the 80psi range, and the fuel (diesel) is cold and coming from the fuel tank, not the Block

It is your truck and you pay the electric bill, Plug it in when ever you want to have instant heat upon starting it.

Kansas Kid · January 30, 2003

Well, I hate to say it but there is an issue with some Duramax equipped trucks that is pretty similar to what you said. When the block heater is used it can cause the check engine light to come on, and will set a code of P0181 which is for the fuel temp sensor. It isn't actually an issue with the sensor, but rather a programming issue. If the block heater causes the ECT to rise too much above fuel temp this code will set. It doesn't actually cause any problem, and getting your ECM update will take care of it. So actually it isn't total BS, other then not plugging the truck in until the temp hits -30 and GM not putting a block heater on the Duramax.

Roofer · January 30, 2003

I have a question....

Is it fine to leave it plugged in all night? And do you disconnect before starting?

I normally don't plug it in, because it is in the garage. Tonight though it is parked outside. It is to get down to 4 F tonight.

bob · January 30, 2003

I leave mine plugged in all night. The owners manual says something about plugging it in for at least 8 hours.

bowtiebob · February 1, 2003

I plug in all night, and then start it with it plugged in. Once it gets going, I get out and unplug. I don't know if this is proper, but it has worked for me so far.

hdmax · February 1, 2003

Why would it matter if you unpluged it before or after start up? It is just a heating element.

Stepside Z · February 1, 2003

I plug my truck in when the temps get down in the teens. Ford says the truck is good for minus 10 deg F (IH says minus 20 degrees) but I don't think the batteries are up to the task. I am planning on buying new batteries next fall. I would try putting a timer on the heater and setting it for 3 hours befor you plan on leaving for work. That should give the truck plenty of time to warm up befor you start it.