Using motor oil as a coolant... Thoughts?

Here's an interesting situation. I read this on another forum, and was wondering if I could tap into the HAMB's incredible knowledge base to get some thoughts and opinions on this.

So this guy is 1200 miles from home and he blows a head gasket... Coolant in the oil, and oil in the coolant... Bubbles in the radiator... Cl***ic head gasket issue.

So he drains the fluids [oil and coolant] from the engine, and fills both of them up with motor oil... Yep, you read that rght... A couple gallons of motor oil right in the radiator, on purpose! No water or antifreeze at all, just oil.

He then procedes to drive the car 1200 miles home.

He claims he made it home with no problem, tho the engine did smoke as it was ****ing a little into one of the cylinders. He says it "consumed" about a gallon of oil on the trip and it only ran on 7 cylinders as one plug was hopelessly fouled from buning oil.

When he finally gets it home, he replaced the head gasket, and replaced all the hoses and the water pump, and has been driving since [2 years now] with no side effects or problems.

Now here's the interesting part. This all happened in the winter, and he says that he had to keep the heater on low because it was putting out a tremendous ammount of heat, but the engine ran a little cooler on the trip home.

The whole thing has got me wondering........ Could this be true? I see no reason it wouldn't work, but I suspect there is some reason that the auto manufacturers didn't design the cooling systems to use oil instead of water. Tho in a way, it would have made a lot of sense to design them that way... Back in the olden days [before green antifreeze] cars were notoriously known for overheating in summer, and freezing and cracking blocks in winter. Also, it would have eliminated the corossion issues ***ociated with cooling systems... So in a way, it would have been better to use oil instead of water.

What say you guys?

 

I don't know of anyone that uses oil in the cooling system & don't know why the manufracturers don't do it. But I remember my dad told me how many people used to run kerosene or fuel oil in their cars' cooling systems, back in the 30's & 40's during the winter to keep 'em from freezing up.

 

Not too sure about the heat transfer capabilities of engine oil. Not that it wouldn't work, but I don't see the radiator cooling off hot oil that well...

 

This may interest you:

http://www.eng-tips.com/viewthread.cfm?qid=225765&page=1

Doesn't really give an answer, but has some suggestions to consider.

 

Well actually, some tractor pullers do run oil in thier cooling systems. I was told that in case a head gasket blew, the coolant getting into the cylinder would not hurt the engine. I think it was more to do with thier induction add ons than anything. As far as using it in an Auto, I would think it would sludge up pretty fast in the cooling system.

 

an old tractor called a Rumley Oil Pull used oil as a coolant

 

Oil is an excellent heat transfer medium, but trying to get something like that flowing on a cold morning would be an issue.

Interesting fix. Very, very, interesting.

If it was a late model he may, or may not have saved his cat converter. 1200 miles of antifreeze will kill one, not sure what 1200 miles of oil would do.

One other thing for the BS alert. There would probably be enough antifreeze left in nooks and crannies, even after pulling block drains, to make the "coolant" oil a milkshake. Just getting the water out would be a huge process for most cars.

 

We have some diesel "Tugs" at work,(utilty tugs,airport),that have 4 cylinder Deutz diesels,which are oil cooled.

Type of oil I do not know.

 

According to my copy of "Marks standard handbook for mechanical engineers", oil has about 1/3 the thermal conductivity of water. I suspect that's the main reason it isn't used more widely as an engine coolant.

 

How long would oil last as coolant? I change engine oil every 3,000 miles and I really never flush out coolant, even though it is recommeneded. If someone were to use oil as coolant, how often would they have to change it? That could get really expensive if the oil were to break down like it does in the engine, which I would think it would. It's not something I really want to try out.

 

I think we have a winner...

Oil is used as a coolant on some tractors, stationary engeines, etc., for the reasons stated. The GSX-R was oil cooled for weight saving reasons, not because oil was a better coolant.

We have seen results from adding external oil coolers on to racing engines drop the water temp as much as 20deg., but water is still the best heat rejection medium available.

 

up til the 60's, a new car had water from the factory. If you wanted antifreeze, you paid the dealer extra for it. And before that the same with alcohol.

Factories used water, cheaper and all the old cars leaked.

I think I also read of aircraft engines being cooled with oil.

I think a good idea. A light oil, like atf or hydraulic oil would be good.
Hafta get rid of the rubber hoses and go with something that can tolerate petroleum.
I don't think it would gum up or deteriorate the fluid.

Too expensive for the factories, but doable for hot rodders.

 

somewhat OT, 911s are air and oil cooled. 14 quarts in a dry sump system with oil coolers.

 

Once, I was kinda thinking about a high-pressure cooling system using R12 as a coolant....tricky but do able I think. 500-600 PSI in the block area and 40-50 PSI in the heat exchanger... with a metering system like an ammonia absorbsion set up.

Oh, well...too many hotrods to ever get to it anyway. MIZ

 

I've been using oil as a coolant in my backhoe for years, works beautifully. Mine has a cracked block allowing water into the oil, so I use oil in both systems. no leaks so far, and it cools fine.

Dave

 

Ok, good answers thus far. The vehicle in question was a 70's model SBC pick-up with no emissions equipment.

It's just one of those things that makes you go Hmmmmmm....

So oil has less heat transfer than water... That's not really an issue, it would only require a different type of thermostat, and maybe a different radiator design to have been done from the factory.

Yes, it does tend to get thick in cold weather, but a different water pump design that was made to pump thicker fluids could solve that.

My point in making this post was not really to probe the "BS factor" of the story... It seems feasable. Infact I believe he did it. It makes perfect sense.

What I'm wanting to know is why Henry and Walter P. didn't consider doing it "back in the day" when they were having issues with water boiling over and freezing. It would not have been that big-a-deal to design it into their motors in the first place. Infact, a single pump could have been used for lubrication and cooling the engine. It could have been designed so oil chang intervals could been extended by 3 or 4 times, plus the system could have been made so that it incorporated safe-guards to protect the motor from running dry.

The designers of the 30's were infact some pretty sharp fellers, and I'm sure this idea crossed their minds more than once... Especially with it being common knowledge that consumers were running kero and heating oil in their radiators...... But something stoped them from designing it that way, and I'd like to find out exactly what it was.

I suspect Bluto might have some insight into this. He seems to know a lot about what was floating around in those designers heads.

Keep the thoughts comming guys. This is interesting

 

Weren't those "oil cooled" engines from Porsche and Suzuki cooled with oil jets spraying the pistons from below rather than using a flow of oil around the cylinders?

dv

 

This reminds me of those stories about guy's putting ****ermilk in a master cylinder
when you ran out of brake fluid.
Or the guys putting sawdust into a noisy trans or rear end.
Or wrapping blown fuses with foil.

 

Couple of reasons are likely... First is safety; if you sprung a leak with an oil cooling system, you'd have flammable liquid spraying all over the hot engine, exhaust, windshield...you get the idea. Second, if the original post about thermal efficiency is anywhere near accurate (and I can believe it is), you'd need a MUCH larger radiator surface to pull the same amount of heat out of the oil. Maybe it would work ok without, but you'd be cutting way down on the overheat safety factor. If you put enough radiator on to be sure, there goes your frontal area, styling, etc.

Using combined lube/cooling fluid has obvious merits, but maybe they don't outweigh the down sides...

 

Some motorcycles do this, just use a small radiator to cool the oil. Not that much different than adding a ****** fluid cooler to a pulling rig.

Interesting fact about oil having 1/3 the thermal conductivity of water. That's surprising.

But, that's probably the reason oil isn't wasn't used as a coolant in cars....it doesn't do as good of a job absorbing and then releasing heat. Water does.

 

i do a lot of work on 6.0l ford diesel's and some times they blow the oil cooler internally and fill the cooling system with oil the reslt is a nasty milkshake like muck and it's very difficult to clean. and the hoses swell and heater core plugs. if there was no coolant at all in the system to mix with it may not have any issues but thats hard to get it all out from the water jackets

 

Early Suzuki GSXR's were oil cooled. Had a big old oil cooler and minimal fins on the engine so the air would help. It's been done and done well.

 

***uming 1/3 heat transfer capacity:
Yes you'd need 3 times the radiator area. All p***ages would also have to be much bigger to reduce pumping loss.
Where does it go? That's as large as the entire front of the car.
You also need to increase the circulation rate by 200% - takes a huge amount of power to pump that much cold oil that fast.

Water isn't the best, but it's the best one that's practical.
Alcohol is better, but it finds leaks very efficiently, and a pressurized alcohol leak is also called a flame thrower.

 

(some) "bobcat" loaders are oil cooled. I agree with the 1/3 efficiency, but on the other hand it takes that much longer to get ALL of that oil "hot". I have seen this done in demo derby cars also. usually 10 wt hydraulic oil.

 

A friend has worked for Suzuki for 20+ years. Tells me that the "Oil Cooled" GSXR's were really just marketing hype. They were air cooled motorcycles that ran larger than normal oil coolers to help with controlling overall heat. (a little more complicated than just a cooler, a 2 chamber oil pump for instance, but you get the idea) They were not truly oil cooled in that they still relied heavily on air cooling. (and that goes for Porsche's, VW's and Corvairs too) The "Oil Cooled" hype came from the perceived need to compete with the water cooled bikes on a consumer marketing level. The Suzuki acronym for this system was SACS, Suzuki Advanced Cooling System which squirted oil at the underside of the pistons in particular along with higher than normal levels of oil circulation. The reason they went this way was both to continue with an already established motor design and to keep the bikes lighter and simpler than the compe***ion, something they were known for.
They went to water cooled in 93 on the GSXR to keep temperatures in check as the horsepower wars continue.

 

VW flat 4,Corvair flat 6?

 

whats wrong with that? been there, done that. had to to get home on many occasions in the dark with no headlights as a factor, you wrap blown fuses

 

The thing you guys are missing about the oil cooled motorcycles is the fact that they are still Finned and have the duct work to make use of those fins as more cooling! so it is not "JUST" oil cooled.. the cylinders and stuff are also air cooled.

 

I don't see the advantage of using the same fluid for cooling and lubing, but keeping both systems seperate.
Having just one and the same fluid doing both cooling and lubing at the same time seems impractical for both manufacturing and use.

If the cooling system is separate from lubing, a more efficient coolant that flows easier can be used at a lower cost.

How often do headgaskets fail on street engines?

 

depends on the engine... ask millions of early ford ****** owners how they liked their four banger