Brain fart, coolant system 1

[SonyAD]

I've just had a brain fart. How about using engine oil for coolant in the engine's coolant system, separately from the oil in the sump. I'm thinking of corrosion prevention and wear protection of the coolant pump. Also, a good, thin synthetic will pour at temperatures where you'd need a lot of antifreeze. Or maybe use a blend of water/engine oil.

Also, if you have a water/oil intercooler, no issue at all if it start to leak, except maybe aged coolant oil mixing with fresher sump oil.

And, finally, easier emergency maintenance for those not mechanically inclined.

Well, is it worthwhile in any way, just more expensive than distilled water, or stupid(why, please)?

10x for your time.

 

[ivymike]

heat capacity and heat transfer coefficient are a couple things you might want to consider.

 

[SonyAD]

What would be the viscosity and base stock with the nearest heat capacity and heat transfer to water? Would the oil thinning out as temperature increases improve cooling through better flow?

 

[SonyAD]

Also, I'm thinking the lower heat capacity of the oil would make for more of a temperature differential when it hits the radiator, improving cooling of the oil there. Would help any bit? Also, engine oil could go higher in temp with no risk of it boiling, even in an unpressurized system.

Anyone done this or know of this having been done?

 

[patprimmer]

I think Isaac's comment was meant to imply that water has substantially higher hat transfer than oil. Oil is somewhat more expensive that water.

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[willeng]

It would be a nightmare, just thinking how many times i have had to drop a bit of coolant out to repair something in a hurry, if this was oil--what a mess. Not to mention the danger of having cars run around dripping or spilling oil all over the roads or tracks.

The system would have to be pressurised to try to stop the oil from popping away from hot spots forming vapour pockets & cracks.
Oil will boil & with disasterous consequences, could you imagine hot boiling oil spraying around in the engine compartment from a cooling system failure, things are bad enough as is with engine oil, p/steering fluid etc.

At Optimum engine operating temperature things are not far off the boil as is & oil would take to long to cool things down quickly once to hot.

I once had a discussion about water as a cooling substance, the comment came up that water is used to cool nuclear power plants & if there was a better cooling substance then it would be used in that particular case--end of discussion.

 

[evelrod]

Y'all are too late. It's already been done by thousands of Model T and Model A drivers in the early 20th Century. Antifreeze was a problem in that as soon as the engine got hot the alcohol based coolant was reduced back to water and since cooling systems of those days did not utilize a thermostat but rather covers with flaps on the front of the radiator that could be opened in sequence as more or less cooling was needed. The major drawback of this system was human error...one little lapse of memory and you had a cracked block or busted rad. Many a farmer and rancher in the snow belt, being of obvious short memories ;-), used coal oil (kerosene to you of the younger generation) as coolant. I don't recall my dad ever mentioning the more obvious problem...fire, so I must assume it worked ok. They managed for many years until ethylene glycol based coolants came to market, mostly after the war.

In the last war years and shortly thereafter, I remember my dad draining the block and rad every night that it looked like it would freeze. We had a few pretty cold winters in El Paso in the 1940's...

Rod

 

[SonyAD]

So, should I risk it and try using oil for coolant with a 2.0 turbodiesel?

 

[ivymike]

you might try doing a simple heat transfer calculation first, with water and then with oil, to see whether it still seems a good idea... or you could just go ahead and try it.

 

[patprimmer]

What effect do you think hot oil might have on hoses and seals.

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[CCycle]

Good point SonyAD.

But how about going a little more into the way out. How about using water based lubricant in the crank case? This fluid would serve for both crank case lubricant and heat exchange. I feel that new engine designs may tend to high temperature top end, even approaching adiabatic. But cooling will still be needed in the cylinder bore and crank.

Twenty and thirty years ago there was quite a little patent activity in aqueous biased lubricants. Some claimed to be able to maintain a serviceable lubrication film with as little as one percent additive in water. The additives were usually amines (like soap).

The only application I remember is the machine tool business. Some of this was used as a cutting lubricant and coolant. I have always wondered if this could be applied to engines. Water does not have gumming or caking break down products. It also has much easier disposal.

 

[SonyAD]

Interesting. Now that you mention it, what effects would soap in crankcase oil have?

 

[Surestick]

In the earlier model (late 80's early 90's?) Suzuki GSX-R liquid-cooled motorcycle engines, engine oil was used as coolant and engine/gearbox lubricant.

 

[SonyAD]

Yes, but what about using oil in a cooling system sized and designed for whater?

The antifreeze in the water lowers the overall heat capacity of the coolant. Maybe to where straight engine oil would be. This just might work. If only I had a jalopy to try this on.

 

[BrianPetersen]

If you want to use the same oil as the engine (even if they are in separate loops, although there is no reason to do so - GSXR's used the same oil) I'm thinking the higher viscosity (and slightly lower density) will dramatically reduce the effectiveness of the water pump. Add to that the reduced heat capacity, and I think you are going to have problems at all but slight load on the engine.

GSXR's use positive displacement gerotor pumps, both for the cooling jacket / oil cooler and for the main pressure circuit. But these engines were designed to work this way from the outset ... and they have fine-pitch cooling fins on the engine itself so that they are partially air-cooled directly. Suzuki has since abandoned air-and-oil cooling on their premium models for traditional water/glycol cooling, which is probably indicative that the air/oil system has its limitations.

Ethylene glycol indeed has about the same heat content as oil (about half that of water), but when mixed with water, the heat content and viscosity get brought into range (and the pump is designed to work with this).

If the objective is to eliminate water (for whatever reason) there are coolants that are designed to be used straight, no water dilution, and without pressure in the cooling jacket. I think it's called Evan's coolant, but I could be wrong.

Pat's right to be concerned about hoses and seals.

 

[MikeHalloran]

In a sense, Corvairs used engine oil as coolant.

There was a weak link; the generic engine oil pressure sensor couldn't take the heat. Its diaphragm would fail, spraying a fine mist of oil all over the engine compartment, where it would be drawn into the (air) cooling system by the fan. The oil- coated fins would become covered with a mud made of dust and oil and become less effective. There was then a race to see if the engine would seize from overheating, or just plain run out of oil and seize.

Did I mention that the passenger compartment was heated by the same air that cooled the engine, after it had been heated by the oily fins and fouled by the smoke from the oil- coated exhaust manifolds?

If you caught one before it seized, you could get a good car for a song. Two dollars to replace the stupid o/p switch, two dollars more to extend it away from the block with pipe fittings, thousands in labor to disassemble the engine's tinwork and clean up the drippy disgusting mess, and months to get the stink out of the upholstery.



Mike Halloran
Pembroke Pines, FL, USA

 

[evelrod]

Mike, what you say is true up to the late '62 models. Most of the '63 and all of the later '64 and up Monzas and Spyders did not have this problem as, GM changed the switch. I owned and raced/rallyed a '64 Spyder from '64 to '65 with no oiling problems in some 27k miles. One problem that you correctly indicate is the heating system. The major problem for me was a copper 'o' ring failure on one of the cylinder to cylinder head joints. We were on a winter rally in NM around Ruidoso and I became very sick, headache...Stopped and got out for a bit, kinda cold but it woke me up. Stepping back into the car it became apparent that it was CO. Rest of rally was with vents open and heater off. Watkins Chevrolet in El Paso fixed the problem on warranty, but I never trusted the heater again and sold the car when we moved to Colorado Springs area.
Sorry, this is a bit off the OP...

However, as I indicated, the oil as coolant is nothing new. It's been done before and in certain climates it works acceptably well. My brother was stationed at Little America and he used diesel fuel as coolant in some of his exposed machinery, if you can believe Jack...which often I do not!

Rod

 

[MikeHalloran]

I had no problems with my '63, but I didn't keep it long.

My '65 used up three switches in ~250,000 miles.

I used RTV on the head gaskets... and kept a window open a little anyway.

The only thing that really bothered me about the heater was the cloud of steam you got in a deep puddle, e.g. everywhere in Boston in the winter.



Mike Halloran
Pembroke Pines, FL, USA

 

[SomptingGuy]

Not to mention the pre '98 Porsche 911 engines.

- Steve

 

[patprimmer]

And the good ol VW. When you hot rodded a VW to 6 or 8 times OEM power, you could still run the cooling fan slower so long as you paid good attention to o air leaks and air flow and distribution in the cooling system and dramatically increased oil cooling capacity.

Regards

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