Sounds like a teapot!

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When I plug in my block heater, within a few minutes I can hear a quiet gurgling sound through the hood. Sounds like a cold teapot that has been put on the stove. Heat seems to be reaching to the valve covers within a few hours, and even the heater lines are warm.

Is there such a thing as an overheating block heater?

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'95 2500 SLT LB 2WD, auto 3. 54, 68,000--Westech gauges, Prime-loc, Brite box, Back-off Box, Line X, Flowmaster muffler, Borgeson steering shaft

 

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The sound you hear is the coolent boiling around the block heater element. I wondered if the boiling would damage the antifreeze ,but was told no by several "experts". The only way the the block heater can overheat is if you run it without any coolent surrounding the element,your radiator would need to be almost empty for that to happen. I doubt if it would damage your engine,but the heater element would probibly burn out in less than 5 minutes.

 

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Thanks, illflem!

 

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Might want to ad... . do not start up the truck with this plugged in. Waterpump starts circulating H2O, and there may be enough air bubbles to blow it out.
The voice of experience has spoken. #ad


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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 59,000 Mi as of 10/21/00.
NRA life member. High power/IDPA.

 

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I wondered about that, Patriot. Thanks for verifying.

 

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How about some Earl Gray to give it some flavor? #ad
#ad
#ad

 

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I prefer cellestial seasonings twinings. (in my best lispy Harvie Firesteen voice!) #ad
#ad

 

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Follow up... is it OK to plug 'er up after just shutting the engine down, while it's still hot?

BTW, Chinese green tea works nicely too #ad
. The color blends in well with the yellowish antifreeze!

[This message has been edited by Kodiak (edited 11-15-2000). ]

 

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Plugging in right after stopping sure beats going out in the cold later to do it,or else forgeting. I've been doing it that way for five years no problem

 

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Thanks again, illflem!

 

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It seldom gets below the 20's here, but if I plug it in while it's still hot, I have almost 140 on the temp gauge when I start it up. This is after a 12 hr shift.

I have a winter front, and this will help a little, I guess.

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 59,000 Mi as of 10/21/00.
NRA life member. High power/IDPA.

 

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I religiously plug in the truck if I know overnight temps will dip to the low 40's or below. I will scan and post the temperature versus friction chart for an engine (if I can find my text book). The chart from my book topped the friction scale at 40°F. Imagine things at the minus side!
I'm glad the heater on these trucks doesn't have the limiting thermostat as most vehicles. I use a timer to keep the electric bill down and only warm the truck for the morning start-up.

Pat. . As for starting the truck with it plugged in. I don't know why that would cause a problem unless you got air in the cooling system which is a NO NO. I've never had a problem. ?

Cheers;
JE

 

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John,I think the block heater does introduce air into the system read my theory hereThe air immediately passes thru the heater hoses into the radiator,since the engine draws coolant from the bottom of the radiator no air passes thru the engine. I wouldn't doubt that it is designed that way.

 

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illflem;

If air was constantly introduced into the cooling system you would get a nice layer of oxidation on the parts, the anti-rust <em>additive</em> in the coolant would finally poop out and it turns a lovely <font color=#fa8072>rust red</font>.
The "boiling sound" should be just that <em>boiling</em>. The water <em>amp; glycol</em> in contact with the element boils and displaces the <strike>water</strike> liquid coolant with vapor. Fortunately convective flows puts liquid <em>coolant</em> back to the element <em>almost immediately</em>. Water vapor is around 1600 times the volume of liquid. Same thing when water boils in a pot on the stove. <em>The &quot;bubbles&quot; are not air but water vapor rising to the surface. </em>

The slushing sound should hopefully be the water pump forcing liquid through the block & head water jackets. <strike>They</strike> <em>Coolant passages</em> are sized <em>(just as lubricant journals)</em> to control flows and thus take a few moments to stabilize.
<em> The extra slurshing after running the block heater? Not sure on this. My guess would be warm & cool liquids mixing and contacting the various engine components along with flowing into a cold radiator called your heater</em>
<strike>I'll re-read this jumble after it posts to see if it makes any sense. </strike>

Cheers;
*JE*

[This message has been edited by JohnE (edited 11-17-2000). ]

 

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John,that's the part of my I idea I was having a problem with. I was assuming that the bubbles formed from boiling were air,but wondered where the air came from,knew it couldn't be O being forced from the H2O. So what you are saying is the bubbles are 100% coolant vapor,right?How come the swishing sound seems to be more noticeable when I use the block heater?

 

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I didnt meat to bring on a scientific debate. #ad

I mentioned this because:
1 Ya got to unplug the dam thing anyway. I havent dont it on one of these, but I'm sure it's easier to unplug it, than it is to replace the heating element.
2 This was a problem "back in the day" when we didnt have fancy schmancy closed cooling systems.
#ad



[This message has been edited by The patriot (edited 11-18-2000). ]

 

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There should not be any air in system because of block heater. Not scientific but mechanical. There is a one-way air check valve(and bi-pass hose) near thermostat. When engine is not running this valve is opened and allows air to escape(if there is any). When the engine is running the valve is closed(the pressure from coolant holds it closed).
This is why on the diesel's you have to have the engine turned off while adding coolant(so any air that is foced into block can escape).
Whooshing sound could be coolant starting to flow thru heater core?

 

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Check this out, I don't plug in until about zero degrees f. It is relatively safe to plug in anytime below 60 degrees f. The block heater would have to succesfully overheat the engine and ALL of the coolant in the radiator and heater core before any damage occurs. If your block gets warm enough, the thermostat will open and your radiator will start to warm. As the block heater warms the coolant, it rises and colder coolant flows up from the radiator to replace it with no assistance from any pump. Actually a lot of external "circulating tank" heaters work on just this principal. They must be installed just right to work properly. All they consist of is a tank with a heating element that is mounted upright aproximately mid-engine. The top of the tank usually has a one-way check valve to prevent backflow. As the coolant perculates(this is the sound you're hearing) it rises to warm the engine. These heaters are used to heat engines that block heaters would be hard to install or do not exsist. Your block heater is almost a plug-it-in-and-forget-about-it affair. Trust me, this is general knowledge here in Alaska. If there's any other info you or anyone else reading this would like to know about winterization, fire away!(e-mail or post is fine) Hope this helps. #ad


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Jason Case
'95 2500 4x4 Auto Reg Cab
BD torque converter and valvebody, #5 fuel plate, BD 4" exhaust turbo back, K&N RE-0880,transmission temp, boost and egt gauges.
Pressure Lock installed

'99 KTM 300 EXC

 

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sixkill
I'm in a disagreeing mood.
"As the block heater warms the coolant, it rises and colder coolant flows up from the radiator to replace it with no assistance from any pump"
Warm air rises, cold air drops. As I recall from my science classes liquid is going to remain where it is.
Cold can't do anything it. I do agree with part of your statement. All of your coolant will be heated because heat is energy and energy can move. The Heat from the coolant heater moves into the coolant molecule the heat continues to move to each coolant molecule that is colder until all are the same tempature as the coolant heater.
The heat from the coolant will also move into engine parts and engine oil. Some heat will be lost in the air surrounding engine.

 

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Try This,
Put a $10 timer on the outlet that you plug into, set it so the heater comes on about 2-3 hrs before you need to use the truck, it wont overheat it, or cost you as much to have a warm truck.
Randy Hutton




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95-2500-ExtCab-LB-4x4-Auto-AMSoil Air Filter, Bypass Oil Filter by others, AMSOIL and Mobil Synthetics, TST 255HP and TransGO Shift kit .