good/best engine block heater?

[slowmover]

good/best engine block heater?


KAT stick on pads, or similar = good
KIM HOTSTART = best (coolant thermosiphon).

No reason not to combine them; but some electrical knowledge about amp draw, etc, will be needed.

Search around on vehicle enthusiast forums, especially where trucks are used by utilities, mines, etc; a fleet mix of gas and diesel engines.

WEBASTO or ESPAR = full independence from utilities

.

[svc]

And the links:
Calix AB
DEFA WarmUp - Start page

As Piwoslaw mentioned, heating the oil is not efficient. You need to get greatest mass, the engine block itself, warm to reduce the time which engine runs on rich mixture.

For winter I just use synthetic 5W-40 or 0W-30 oil regarding of manufacturers specs. That's thin enough even in -40 Celsius

[Diesel_Dave]

I think an important thing to remember is that preheating actually helps the efficiency in 2 different ways.

First, is the fact that the warm engine is more efficient because there's less heat transfer.

Second, a warm engine will have much lower friction, especially upon startup.

A block heater addresses primarily the 1st issue, an oil pan heater primarily the 2nd (obviously there's some crossover too). Immediately upon startup, there is relatively little oil between all the friction surfaces, therefore high friction. The colder the oil is, the thicker the oil is and the longer it's going to take for all the oil to get where it needs to be. Also, cold oil takes more energy to shear so friction will be higher due to that as well.

This is why engines that are used for long trips last longer than ones used for only short trips--frequent cold starts increase the overall wear greatly. Something to consider is that pre-heating (particularly the oil) can help reduce engine wear in addition to helping your FE.

[comptiger5000]

Or, as the best option, do both. Maybe a 125 watt on the oil pan, and a 500 watt block heater, for example.

[svc]

Thing to remember is also the total efficiency. Will the preheating cost more in electricity than gasoline saved? Or will Webasto or Espar (Eberspächer in the EU ) burn more fuel than it saves?

[GRU]

i have a block heater on my Escape but i ordered a oil pan heater for my Civic so i will see which works best.

I belive that the oil pan heater will actualy heat the whole engine but the coolant will not be at warm as with a block heater. As long as the oil pan heater warms up the engine a little i'm happy with that because the oil will be warm where with a block heater only the coolant is warmed up.

[slowmover]

Originally Posted by svc

Thing to remember is also the total efficiency. Will the preheating cost more in electricity than gasoline saved? Or will Webasto or Espar (Eberspächer in the EU ) burn more fuel than it saves?

The fuel savings may not ever be as great as the increased engine life, or, mean time between overhauls.

We can all come up with scenarios of vehicle type and use, etc, where one factor will sway a decision. But assuming folks are buying the right vehicle and trying to keep it the maximum number of years/miles (maybe 20 years and/or 250k miles) then prudent use of pre-heating seems a no-brainer to reduce start-up wear.

Same for a winter front on a diesel. One need not live in a cold climate to conduct some simple experiments on a vehicle kept two decades to figure best use of energy.

[Rick Rae]

Originally Posted by GRU

I belive that the oil pan heater will actualy heat the whole engine but the coolant will not be at warm as with a block heater.

I thought the same, but the jury's still out on the CARDIS. I ran an experiment in early Fall using a 300W magnetic oil pan heater (Kat's Magnum). It definitely did the trick for the oil but didn't seem to have much effect on the engine block or coolant temperatures:

 Time    On Time  Ambient  Block  Coolant  Δ A:B  Δ A:C  Δ A:B Adj  Δ A:C Adj	
 8:54 AM   0:00	   56.0	   63.6    62.6	     7.6    6.6	    0.0        0.0	
10:00 AM   1:06	   55.6	   63.1    62.6	     7.5    7.0	   -0.1        0.4	
11:00 AM   2:06	   57.4	   64.3    64.4	     6.9    7.0	   -0.7        0.4	
12:30 PM   3:36	   59.4	   66.7    66.2	     7.3    6.8	   -0.3        0.2	
 7:00 PM  10:06	   57.9	   70.2    69.8	    12.3   11.9	    4.7        5.3	
10:30 PM  13:36	   53.1	   68.2    68.0	    15.1   14.9	    7.5        8.3	
 9:00 AM  24:00	   48.7	   63.2    62.6	    14.5   13.9	    6.9        7.3

"Block" ("B") is the external block temperature measured with a thermocouple under a snugged bolt head near the top of the engine. "Coolant" ("C") is the temperature reported by my Ultragauge; I haven't yet looked into where that sensor lives. Because of the offset between the ambient temperature and the other readings, the last two columns are adjusted to remove the offset. (I didn't concern myself over where the offset originated as the relative values were the ones of interest.)

I literally ran this test for 24 hours, to give the oil pan heater every opportunity to show its stuff. As you can see, the heater apparently didn't do much in the way of raising engine temperatures (though it DID seem to hold onto some gains as the ambient temperature dropped overnight).

I want to do another more controlled test once the weather's significantly colder, but my current impression -- for the heater I used, where I put it, on my car -- is that I'd need a block or coolant heater if I want to warm more than the oil.

(Also still pending are actual operational tests... e.g., looking for a difference in warmup profiles with and without the oil pan heater in roughly equivalent temperatures. I'm thinking whatever heat is in the oil will be transferred to the block once the engine's started, but I question if it will make a significant or even detectable difference.)

Comments invited.

Rick

[roosterk0031]

Your heater is thermostatically controlled, do you know the on/off temps? If the relatively low mass of the oil & pan heat up, maybe it's cycling and will never heat the coolant any more than that +10-15 degrees your test showed.

If you can get the same heater stuck to the block it might stay on longer and might show a bigger change.

[Rick Rae]

Originally Posted by roosterk0031

Your heater is thermostatically controlled, do you know the on/off temps?

The setpoint is 238F.

If the relatively low mass of the oil & pan heat up, maybe it's cycling and will never heat the coolant any more than that +10-15 degrees your test showed.

Exactly. And there's the thermal loss from the block to ambient to consider as well.

If you can get the same heater stuck to the block it might stay on longer and might show a bigger change.

Aluminum block.

Not to mention it being a tiny, tightly packed engine with not much in the way of large flat unallocated surfaces. I think an actual block or coolant heater will be the way to go for that (for the CARDIS, at least).

Cheers,
Rick