Block Heater problem

if you have a multimeter just use the ohm's setting and check the prongs on the cord the two flat blades should have about 350 ohms across then and no reading from either blade to the ground pin. If no reading then the block heater is open circuit or the cord isn't plugged in properly on the heater. If you plug it in over night in the morning if you put your hand on any part of the exposed engine block it should feel warm to hot. Also there will be no instant heat from the heater that will take a few moments to start happening depending on the OAT as the water pump has to move all the cold coolant from the core.

 

Frank:

Um, last fall when I checked my cord plug before the cool weather, my Fluke indicated around 35 ohms. For a resistance load, power in watts is:

P = V^2 / R

If you want to use an RMS-corrected value like 117, that's fine for V. Most folks will use values from 115-120 and it will have little effect.

P = 117^2 / 35 = approx. 391 watts. About 3.4 amps.

If you use a value of 350 ohms:

p = 117^2 / 350 = approx. 39 watts. About 0.33 amps.

Note that when you measure resistance at the plug, you're also including the resistance of the cordset as well.

I would recommend the original poster obtain/borrow a clamp-jaw ammeter, the basic ones will measure current, the better ones can determine power, either "corrected" power or not.

jay

 

The only way that I knew it was working was by actually putting my face near the tank with pink fluid. I could feel the warmth on my face. The block only seemed to get as warm as about 50-60 degrees, that's just my guestimate.

The block heater on my Sienna really warms things up, it's a big heating element and is contact directly with the radiator fluid. The cooling hose near the top of the engine is very warm to touch and hot air is coming out of the vents in 2 minutes. I wonder if since the system in the Prius is different, it doesn't warm the cabin air as quickly?

 

That is a very good point you bring up.

Remember the Prius heater, also the one used in the Echo here, is *not* an immersion coolant heater. It fits into a hole in the block, is smeared with a thermal transfer grease, and heats the aluminum block.

I'm sure it works, but an immersion coolant heater works so much better. Even a frost plug heater.

My old 1984 Ford F-150 at the hobby farm has a Temro 1,000 watt circulation coolant heater plumbed into the heater hose. It doesn't matter if I have it parked in my insulated detached garage or the old barn, even at -40 after being plugged in for an hour the block is *very* warm.

You start it and get instant hot air out the heater.

When I use the EBH at my hobby farm, my Prius warms up *much* faster. If I don't use the EBH, in temps of -25 C I can slowly drive the 4.5 km sideroad to the highway, and there is barely any heat coming out. After a 3-4 hour plug in, I get plenty of hot air by the time I get to the highway.

Also, I speak from experience here, you *need* a winter front especially in temps of -20 C and colder. The motor doesn't produce much waste heat, so at the very least you will freeze your little pinkies off in city driving. Search the many humorous posts I made last winter on *that* topic.

With the lower grille and two upper slits blocked off, I have plenty of heat and have a gained approx 16 MPG overall. Last winter at -35 C and colder, I averaged 9.8 l/100km. This winter at -30 (Winter front, Mobil 1 0W-20) I averaged 6.4 l/100km.

 

I've measured mine and can verify the 3.4 amps number for a working heater. My engine is around body temperature in a cold (approx 32 F) garage after 3 hours or so. It doesn't seem to get any hotter if on all night. I use a timer that comes on about 2.5 hours before I leave for work. I also put a large cardboard sign on my windshield telling me to unplug the heater so I don't try to back out with the extension cord still plugged in.

- Tom

- Tom

 

Tom:

It's quite common around here to see cars putting down the street with an extension cord whipping behind, like a skinny, angry, yellow snake.

These cars are usually driven by little old ladies, and are oblivious to pedestrians yelling "HEY LADY! YOUR EXTENSION CORD IS STILL PLUGGED IN!"

jay

 

There is a lot of good information in the thread called "So I figured out how to install my block heater" including a picture of the instructions for installation (page 14).

I have never driven away with mine plugged in. I wrap the extension cord around my outside rear view mirror where I can't miss it when I get into the car.

Allan de

 

your right I was running on no coffee when I replied to the OP

 

My estimate of 50-60 was based on just touching the top of the engine block with my fingers. When I still wasn't sure, I took a bit of snow and dropped it on the spot next to a row of 4 black plastic plugs and it melted...that was on a day that was -10 degrees.

 

Dr Fusco:

Ah, but is that Corrected Power Factor to RMS or not?

:blink:

Just kidding big guy. My condo neighbors have another wine sampler going on and I'm feeling a bit ... silly ... at the moment.

j

 

E:

Hmmm, around here it's usually little old ladies that do that.

Must be the wine. Better snooze.

j

 

Frank:

Hehehehe it's so rare I catch you I just had to jump at the chance. Feel free to retaliate, I've been sampling wine for the past hour and am feeling no pain at the moment.

jay

 

Allan, that's not a bad idea except I have visions of tearing off my rear view mirror because I am dumb enough to miss it especially at 5 AM when I leave for work. I sure hope that never happens to you.

- Tom

 

Tom - Thanks for the concern - I figure if I can't see the wire I'm probably not safe to drive. Its big, ugly and yellow.

Allan de