(And no, I don't mean glowplugs)
Seen a few threads where people are complaining about their diesels not chucking out the heat on cold mornings. Seems to be an average 2.5 miles before anything worthwhile starts to come through.

I've already started a thread in the doblo section but there are querries in almost all sections regarding diesels taking an age to warm up so I thought I'd try here.
It's not just diesels that would benefit from a warm start though.
I toyed with the idea of a webast or similar but these are very expensive.
There are pads and other things which are designed to warm the oil but i was looking at http://shop.conrad-uk.com/car/car-equipment/car-comfort/car-van-air-conditioning/857490.html
Which heats the coolant and pumps it round. So the cab should warm up as soon as the fans are turned on. Added bonus would be better fuel economy & longer engine life.

I did feel, though, that the price of these things was a little steep considering similar products across the pond sell for $50.

Has anyone come across a similar product for a better price?

Maybe if enough of us were interested we could ask for a discount?

I wonder if heating the coolant is the best way to go, though? You need a pump as well as a heating element, which potentially reduces reliability and increases cost.

The cheaper American ones seem to be sump heaters: either a thing which looks remarkably like a kettle element (which looks as though it could replace the oil drain) or a ceramic pad to pop into the sump. Unfortunately you can get 12v, 24v, or 110v, but no 240v.

I think i replied something similar on the Doblo forum, however...

UK Company Kenlowe have been making electric engine preheaters for years, a simple device that plugs in pumps the water round and can heat the engine and all the coolant to operating temperature in about 20 mins, these things are about 3Kw which is about the same as a kettle.
the advantage of the kenlowe system is they do equipment that allows the system to be timed and to control the interior cabin fan so as to heat the whole car before you have to get in it, on a cold morning.

looking a couple of the sump heating pads, the down side i see with them is the huge amount of time they take to warm the oil. and that without that oil circulating it means the rest of the engine is cold on start up, which will very quickly cool that warmed oil back down again once it's flowing through a freezing engine block.

most countries in northern areas with very cold climates use electric engine preheaters to keep the coolant and engine warm otherwise they would never start and risk freezing the coolant.

Diesel becomes very thick in the cold weather so one of those heating pads might be better suited to being attached to the fuel tank?

Why should a pre-heater take longer to heat the oil than the water? Have you discovered a new law of thermodynamics? Heat will -- in any event -- be conducted through the block utterly regardless of which fluid is warmed.

I think people in Siberia light fires under the deisel tank (and use very strong antifreeze) -- after starting, exhaust gasses can be used to prevent the deisel from gelling (or the tank can be heated by a simple water/deisel heat exchanger).

A heater pad stuck to the underside of the sump has to permeate the metal of the sump before it can heat the oil, the metal its self is able then to radiate off some of that heat before it gets into the oil etc. the quoted figures i found stated "can heat the oil from 40 degrees to 70 degrees in 1.5 hours, doesn't really matter if thats degrees C or F in my view thats a long time however you look at it, and doesn't represent a huge difference in temperature. where as heating the coolant, this radiates heat into the main metal of the engine block, and is pumped arround constantly to warm all parts of the engine. (i know there is a counter argument as to it not heating the crank)

I appreciate that the heat from the oil may travel up to some degree but not so much as to heat the area around the cylinders to operating temps. you certainly couldn't heat the cabin in this way.

by keeping the cylinders and head warm you are keeping the oil around them warm which means its ready and waiting at peak temp when you start the car.

the pad heaters i've found don't seem to be available in anything over 1KW and for that size and power output are pretty expencive. the ones advertised as Sump heaters seem to be about 250W which is still a long way off the 3KW of the water heaters, this is why they take much longer to put heat in the engine.

the heat will be conducted as you say but... you need a powerful heater to warm a large item like the engine block 250W just isn't enough and in this case the pumping of the coolant around the block does a better job than just heating one small spot

the more energy you put in, in this case 3KW v 250W the more heat you get out and thus the better the engine is heated

The pad ones I've seen actually sit inside the sump.

Andy, thanks for your indulgence. I wanted to put it here for a wider audience really. I would have thought that a warmer block would benefit petrol and diesel - it's certainly something they do in r/c cars, racing cars, planes, generators (even). So I was hoping that a wider audience would have more ideas?
Fingers, the item in the link has a pump and an element. If the pump in this is as good as the £10 water pump in my washing machine, it should be good for at least 15 years (and that was one load per day & at least 5 loads over the weekend).
Looking at the options, a coolant heater is a much better idea than simply warming the sump. The hot coolant is pushed all around the engine block and the heater matrix, so giving at least warm air the moment you turn the ignition - so it will quickly take the chill off the cab and quicker to defrost the screen - and I can't see any reasoon why the thing cannot be left plugged in whilst the engine is running (given a 100m cable reel & quick release plug ). As Andy was saying about the pads, you not only have to warm the metal pan but also any heat will quickly be lost from the cold air moving around under the car (and the rising heat will move it quicker?).
I know we don't get the same depth of winter here like they do in other countries but tonight is forecast -7 C & that is damned cold. I don't know what the temperature of combustion is but it cannot be doing the engine much good to be taken from -7 to combustion temps in a split second - this thermal shock also must have a knock on effect with other parts of the engine as well.
Regarding the gelling of diesel, I remember a time when we used to light fires under the tanks of artics during the arctic conditions on the m62 in order to liquify the gelled diesel but I've not seen that done for years now since they started adding stuff to the fuel.

Make your own for £20 then http://www.ebay.co.uk/itm/smeg-dish...shwashers_PP&hash=item4600bf37f1#ht_500wt_922

I think the auto ignition point of diesel is above 250degrees C I'm not entirely convinced on the thermal shock argument however, uneven heating of the engine when first running would cause uneven wear. If properly preheated the glow plugs would never be needed.

fingers99 said:

I think people in Siberia light fires under the deisel tank

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people in the uk used to do that before diesel anti freeze became available to the public.

AndyRKett said:

Make your own for £20 then http://www.ebay.co.uk/itm/smeg-dish...shwashers_PP&hash=item4600bf37f1#ht_500wt_922

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that will blow up if left on a car when engine is running at full temperature

It might leak from the pump after a period of time, but it certainly wouldn't 'blow up' that's somewhat dramatic.

The heater is a straight through metal pipe so no weak point there, and the simple addition of a solenoid valve would isolate it from the rest of the cooling system when not plugged into the mains, it's not a perfect job but it is far cheaper than the very expensive dedicated systems.

I presume your main concern would be the temperature and pressure of the sealed system but as the thermostat in most fiat engines is rated to open at 87degreesC and this would be connected external to this it's likely the only time it would experience higher temperatures is if there was some other failure in the engine.
I don't know the pressures in the engine cooling system? They are not the high pressures they used to be in older cars I think this would cope, but then that's what experimentation is about, as long as you don't do anything silly and put your self in danger

Surely the thermostat would prevent the coolant heater working correctly by stopping or at least restricting the flow of coolant when the engine is cold?

Shadeyman said:

Surely the thermostat would prevent the coolant heater working correctly by stopping or at least restricting the flow of coolant when the engine is cold?

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Well, it would until it was warm enough for it to open.

I think that kind if heater (from the dishwasher) would work. Pressure isn't, I think, at a touch over 1 bar, going to have any great effect. Might not be robust enough (looks to be a lot of plated mild steel there) for prologed use, but could be toughened up. And if they're cheap enough..........

I've no drive or garage at the house, so I won't be trying it, but someone should.

AndyRKett said:

It might leak from the pump after a period of time, but it certainly wouldn't 'blow up' that's somewhat dramatic.

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it will blow up, cooling systems run at very high pressure, domestic appliances don't

1.2 bar is hardly "very high pressure". Who knows? Suck it and see? You could easily enough knock up a jig to test it for leaks. Bits of bike inner tube (with valves) a few hose clamp, some water and a pump with guage.

After a bit of investigation it seems that uk mains water pressure as you would see in a dishwasher is in excess of 2bar can't pin it down exactly because it varies from place to place but some websites suggest its as high as 6 bar,

The pressure cap on both my puntos is designed to release pressure at 1.4bar which is 20psi this is obviously way below mains water pressure. My central heating has a higher pressure than this.

The construction of the Dishwasher heater is of steel pipe with the heating element around it, the pump is of a pretty hefty looking plastic and metal, connected by a thick rubber hose held on with clips, it is a pretty robust piece of kit, and I don't doubt it could cope with the much lower pressures in a car coolant system. In any case the pressure cap would be blown long before the pump or heater 'blew up' as much as something would blow up at only 20psi

AndyRKett said:

After a bit of investigation it seems that uk mains water pressure as you would see in a dishwasher is in excess of 2bar can't pin it down exactly because it varies from place to place but some websites suggest its as high as 6 bar,

The pressure cap on both my puntos is designed to release pressure at 1.4bar which is 20psi this is obviously way below mains water pressure. My central heating has a higher pressure than this.

The construction of the Dishwasher heater is of steel pipe with the heating element around it, the pump is of a pretty hefty looking plastic and metal, connected by a thick rubber hose held on with clips, it is a pretty robust piece of kit, and I don't doubt it could cope with the much lower pressures in a car coolant system. In any case the pressure cap would be blown long before the pump or heater 'blew up' as much as something would blow up at only 20psi

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but that pump you posted dont connect to mains water it pumps around and out, not in

AndyRKett said:

After a bit of investigation it seems that uk mains water pressure as you would see in a dishwasher is in excess of 2bar can't pin it down exactly because it varies from place to place but some websites suggest its as high as 6 bar,

The pressure cap on both my puntos is designed to release pressure at 1.4bar which is 20psi this is obviously way below mains water pressure. My central heating has a higher pressure than this.

The construction of the Dishwasher heater is of steel pipe with the heating element around it, the pump is of a pretty hefty looking plastic and metal, connected by a thick rubber hose held on with clips, it is a pretty robust piece of kit, and I don't doubt it could cope with the much lower pressures in a car coolant system. In any case the pressure cap would be blown long before the pump or heater 'blew up' as much as something would blow up at only 20psi

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The pump you posted is a circulation pump, the only pressure it experiences is the pressure it creates when its working.

I take on board what you are both saying except the circulation pump IS directly subject to the inflow of water at mains pressure, and every manufacture (ive found so far) requires that the mains water pressure be a minimum of 20psi max 120psi Inorder to provide sufficient water pressure through the circulation pump to clean the dishes properly, if you think how a dishwasher works, using water pressure to spin the washing rotors (at great speed) then a fair amount of pressure from the circulation pump is also required.

There is a separate drain pump in most dishwashers which operates at a much lower pressure, the more I look into this the more I see this type of pumps is more than up to the job the down side is the pump motor is in the region of half a horse power which is serious overkill for this application, and would probably be far more powerful than the engine water pump.

AndyRKett said:

I'm not entirely convinced on the thermal shock argument however, uneven heating of the engine when first running would cause uneven wear. If properly preheated the glow plugs would never be needed.

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Companies like Miele and Dyson have invested millions in research because of the problems of thermal shock causing fabrics to crease badly and wear out prematurely. Not many years ago, only top of the range washing machines (such as Miele and dyson) had cold fill only.

Something like a pyrex oven dish will crack/shatter if taken from a hot oven & dunked in cold water - thermal shock.
And whilst something like an engine block might be OK to go from sub zero to combustion temp in a split second, there are many items in there which aren't quite so tough.
You also have to consider the properties of the many different materials in an engine, rates of expansion/contraction can vary greatly.

Shadeyman said:

Surely the thermostat would prevent the coolant heater working correctly by stopping or at least restricting the flow of coolant when the engine is cold?

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The coolant system is, essentially, three parts.
Part one is the engine, reservoir and pump.
Part two is the heater matrix.
Part three is the radiator.

The matrix is isolated via the cabin on the hot/cold dial
The radiator is isolated via the thermostat (with, I believe, a small hole to allow minimum circulation to keep the AF in the rad 'fresh').


The idea of the AF preheater is that it heats the AF in the block to bring the block up to temp, with the block warmed up, the engine can be started & AF then allowed to circulate through the matrix, giving at least some heat to the cabin.


As the pump will be brushless, I doubt there would be a problem with the car's water pump being more powerfull.