Just thinking does anyone know what temp the heater block keep the engine at when pluged in. Its -25 c outside. Im just curious.
Neil
Neil
Stock Heater block temp
- Thread starter nbenjamin
- Start date
nbenjamin said:
It doesnt get that hot but enough that when I start my Envoy, its about a line and half up from minimum temperature on the gauge. Im going to guess (I can verify this with my scantool in the next couple days I suppose) that it probably heats the coolant in the water jacket somewhere in the area of 100-130f, depending on how long its plugged in for. I used to put mine on a timer set for 4 hours before I left in the morning.
However, once the heated coolant circulates, the engine warms up much faster I noticed. IIRC, the block heater was rated at 400w.
Little bit of information Im remembering after posting that... at one point GM added thermostats to their block heaters - especially to the bigger ones for v8 engines, as to not set a SES and a DTC (because the vehicle would 'cold start' at warm coolant temps and think something was wrong with itself). A lot of people bypass the thermostat on the block heater, which prior to fiddling with it, it will only allow the block heater to work if its 0f or below out. You can find this info on the web. It seems that after 2005 is when the block heaters had the built in t-stats. Dont know if that applies to the one you are looking at or not. Not sure if the I6 block heater ever got a t-stat on it, but you can tell by the way the plug looks. It will have a hump on the plug before it reaches the block heater itself.
Some interesting reading here: http://ecomodder.com/forum/showthre...lock-heater-redneck-re-engineering-12260.html
Ok. Today officially marks the "MichEnvoyGuy I6 Block Heater Experiment" day 
Not only to answer nbenjamin's question, but also for mine - and Im sure others curiosity.
I went to my Envoy this morning and plugged in my scan tool. The Envoy hasnt been started in 2 days (Ive been sick with the stomach flu). My scan tool read the ECT at 26*f. The outside temperature was 28*f.
I noted the time: 11:28am. I waited until 11:30 exact to plug in the block heater - might as well make it an even time to satisfy my OCD and to make this easier to track!
I went back inside to warm up and hit the john (told you I had the stomach flu, didnt I?!)
Just checked it again at 11:45 exactly. The scan tool reports the ECT is at 44*f. The outside temperature is 29*f now.
I will check it again every 15 minutes and record my findings. Then, in a few hours I will report back how hot the block heater gets the coolant at certain time increments.
Can you tell Im bored today and sick of being restrained to this house?
Not only to answer nbenjamin's question, but also for mine - and Im sure others curiosity.
I went to my Envoy this morning and plugged in my scan tool. The Envoy hasnt been started in 2 days (Ive been sick with the stomach flu). My scan tool read the ECT at 26*f. The outside temperature was 28*f.
I noted the time: 11:28am. I waited until 11:30 exact to plug in the block heater - might as well make it an even time to satisfy my OCD and to make this easier to track!
I went back inside to warm up and hit the john (told you I had the stomach flu, didnt I?!)
Just checked it again at 11:45 exactly. The scan tool reports the ECT is at 44*f. The outside temperature is 29*f now.
I will check it again every 15 minutes and record my findings. Then, in a few hours I will report back how hot the block heater gets the coolant at certain time increments.
Can you tell Im bored today and sick of being restrained to this house?
Ok something strange is happening...
For about 45 mins the temperature was increasing. When I did my 12:30 check, the ECT temp went down 10*f
What concerned me is the ambient temperature is now 32*f. Do I have one of the cords with the infamous built in thermostat?!!?!?
So I disconnect the cord at the block heater and inspected it - there is no telltale 'hump' in the cord where the thermostat should be. I checked the male end, same - no indicator of a built in thermostat
The block heater itself was hot to the touch and the cord was slightly warm. When I replugged in the block heater cord to AC power, it did a little 'arc' like when you plug something in that requires a higher power draw.
I have to assume that maybe the warm coolant shifted out of the water jacket somehow and cold coolant is coming in?? I thought for sure by now, an hour and 15 minutes after plugging it in, I'd be at least at 90*f especially seeing that the block heater is rated for 400w!
Next ECT reading: 2:00pm
For about 45 mins the temperature was increasing. When I did my 12:30 check, the ECT temp went down 10*f
What concerned me is the ambient temperature is now 32*f. Do I have one of the cords with the infamous built in thermostat?!!?!?
So I disconnect the cord at the block heater and inspected it - there is no telltale 'hump' in the cord where the thermostat should be. I checked the male end, same - no indicator of a built in thermostat
The block heater itself was hot to the touch and the cord was slightly warm. When I replugged in the block heater cord to AC power, it did a little 'arc' like when you plug something in that requires a higher power draw.
I have to assume that maybe the warm coolant shifted out of the water jacket somehow and cold coolant is coming in?? I thought for sure by now, an hour and 15 minutes after plugging it in, I'd be at least at 90*f especially seeing that the block heater is rated for 400w!
Next ECT reading: 2:00pm
Let's do some estimated math. Isn't this stuff taught anymore?MichEnvoyGuy said:I thought for sure by now, an hour and 15 minutes after plugging it in, I'd be at least at 90*f especially seeing that the block heater is rated for 400w!
1 kilowatt-hour = 3412 BTUs (British Thermal Units). So 400W applied for an hour, will give you 1365 BTus. Since one BTU is the energy required to raise a pound of water by one degree F, then 400W-hour of energy can raise 1365 pounds of water by one degree, or 136.5 pounds of water ten degrees. Water weighs about 8.3 pounds per gallon, so that's about 16 gallons. So let's say the water jacket involves 4 gallons, so you might expect 40 degree rise in an hour of a 4 gallon container.
EXCEPT:
The water is surrounded by over a hundred pounds of steel and aluminum with its own temperature capacity. I'm not doing the math for this.
Much of the heat is carried away by radiation to the air and conduction by moving air that wafts over the surface.
SO:
The most optimistic 40 degree rise in an hour using 400W is likely to be only 5 or 10 degrees.
CONCLUSION:
Block heaters are meant to be left on all night to make sure a 0 degree engine block is kept near 30 degrees, at which temp the fuel has a better chance to vaporize and ignite. Not to get the block up to 100 degrees where the coolant is going to heat the cabin any faster after engine start.
the roadie said:
Not disagreeing with your assertions or math at all, but makes you wonder why GM would install a thermostat on the cords of 06+ block heaters to only come on below 0*f? The PCMs were setting a DTC because the ECT was recording temps of +100f over the ambient temps and the PCM would think something was wrong. Not to mention its GM's recommendation to only run the heater 4 hours at a time. Seems GM didnt calculate properly on their part. You'd have to leave the block heater plugged in for a day or two to heat the block +100f over the ambient temperature!
Any which way, the boiler guy is here fixing our heat, I missed the 2pm ECT reading. Im switching it to 230
Block Heater Experiment out of MichEnvoyGuys stomach flu day off of work boredom: FAIL 
Ill tell you why.
While the ECT may be in the general area of the block heater, it obviously isnt directly submerged into the same jacket of coolant as the block heater..Read on:
At 3pm, I got hungry and it was time to check the ECT via scan tool anyway. I hooked up the scan tool, turned the key to on, connected and the ECT was at 50*f. Whatever, its 35*f out. I was thinking either my block heater was bad or ... who knows. My ECT is brand new.
Started the truck with the scantool still hooked up. Within 5 seconds of starting, the coolant temperature via ECT reading jumped from 50*f to 112*F. I had ever so slightly warm heat out of the vents. By the time I reached the end of my street (~1/2 mile), I was at 161*f ECT reading.
After ~3 hours, it made a remarkable difference but not one you'd immediately see at the ECT reading before the truck was started. After I started the truck, it really circulated the heated coolant, apparently right over to the ECT area too.
I havent used the block heater in 2 years or so, I didnt remember its past operation aside from I hated the orange plug sticking out my front grille/bumper area. I noticed that during this trip, with the block heater pre-heating the engine for 3 hours, my avg economy on my DIC did not decrease. However, any other day with these temps, during warm up it would decrease anywhere from .2-.5mpg average and slowly work its way back up to my running avg throughout my daily driving.
Sorry I couldnt produce the results the OP was looking for.. at least not directly. However, in my little test, Im going to conclude that ~3 hours of the OEM block heater, will get your engine to +60*f above the ambient temperature. Im sure if you left it plugged in longer, you'd attain higher numbers
Ill tell you why.
While the ECT may be in the general area of the block heater, it obviously isnt directly submerged into the same jacket of coolant as the block heater..Read on:
At 3pm, I got hungry and it was time to check the ECT via scan tool anyway. I hooked up the scan tool, turned the key to on, connected and the ECT was at 50*f. Whatever, its 35*f out. I was thinking either my block heater was bad or ... who knows. My ECT is brand new.
Started the truck with the scantool still hooked up. Within 5 seconds of starting, the coolant temperature via ECT reading jumped from 50*f to 112*F. I had ever so slightly warm heat out of the vents. By the time I reached the end of my street (~1/2 mile), I was at 161*f ECT reading.
After ~3 hours, it made a remarkable difference but not one you'd immediately see at the ECT reading before the truck was started. After I started the truck, it really circulated the heated coolant, apparently right over to the ECT area too.
I havent used the block heater in 2 years or so, I didnt remember its past operation aside from I hated the orange plug sticking out my front grille/bumper area. I noticed that during this trip, with the block heater pre-heating the engine for 3 hours, my avg economy on my DIC did not decrease. However, any other day with these temps, during warm up it would decrease anywhere from .2-.5mpg average and slowly work its way back up to my running avg throughout my daily driving.
Sorry I couldnt produce the results the OP was looking for.. at least not directly. However, in my little test, Im going to conclude that ~3 hours of the OEM block heater, will get your engine to +60*f above the ambient temperature. Im sure if you left it plugged in longer, you'd attain higher numbers
the roadie said:
Shut up!!
Ive been bored, so sue me
And it was a great way for me to boost my post numbers and kept me away from the 'post-whore' thread...lol
I wasn't being sarcastic. I would have used purple font for that.
I'm seriously fascinated by real-world data that makes me re-examine a mathematical model I thought was close to being right. Thx!
I'm seriously fascinated by real-world data that makes me re-examine a mathematical model I thought was close to being right. Thx!
the roadie said:I wasn't being sarcastic. I would have used purple font for that.
I'm seriously fascinated by real-world data that makes me re-examine a mathematical model I thought was close to being right. Thx!
Oh your mathematical model Im sure was absolutely correct by stating it could heat 4 gallons of coolant 40*f per hour, however I think you might've been a little liberal when you surmised the cooling effect of the water jacket to bring that down to 5-10*f effective degree rise per hour. I think my little experiment showed that 400w can heat 4 gallons 40*f in an hour, and apparently 20*f is lost due to cooling off. So 20*f rise in coolant temperature per hour in the jacket, 20*f x 3 hours = the 60*f rise OVER ambient temperature I saw with the scan tool.
I have it set on timer for tomorrow and plugged in already.
Guess I will revert back to my old ways from a few years ago when I would use the block heater all winter long to ease the warmup period mpg drop.if its -10deg c out side shouldn't my scangauge show a water temp of -10 ? , its shows 4 deg every morning , even if i plug in my heater block .
Wyle
Member
- Dec 4, 2011
- 200
nbenjamin said:
Thank goodness for coolant. At -10 deg C you'd have ice in your block not liquid water. And since water starts to EXPAND below 4 deg C, you'd be blowing freeze plugs (if our engines even have them) but probably not at -10C. "Antifreeze" in the coolant system does just that. It drops the freezing point of the coolant mixture well below 0 deg C (depending on the mix).
If your coolant temp is 4 deg C every morning, either the heated coolant hasn't circulated to where the sensor is or your block heater possibly has the built in thermostat that has been mentioned.
Wyle said:
Do you really think that I being Canadian would think that there is water in my engine ?? I used the the term water temp only because that's what it's called in the scangauge definitions for engine coolant.
My heater block does not have the thermostat and if the heated coolant has not circulated why is my scangauge showing 4 deg if it's -10 outside. That was my question Also it shows 4 even when the heater is not plugged in.
But I thnk I figured it out
Wyle said:
Scangauge actually shows a negative (-) but is so far to the left of the digit that I didn't noticed it. So my measurement were actually close when the plug was off and was correct when it was on. The temp out side was around -4 5. The winchil factor made it close to -10. The truck was not really in the wind