Questions on Liquid Loops for Cars

I have a 2005 Camry. I have gotten into liquid cooling for computers. I’m noticing the similarities. In computes you have fans, radiators, fittings, tubes, and water blocks. Comparing the two applications I have some questions on the differences.

  1. Why do cars not use compression fittings?

My car uses all barbed fittings with clamps. In computer cooling, compression fittings are generally preferred, because it makes use of a o-ring (or possibly multiple) and are seen as more leak resistant.

  1. Why do cars not make use of push pull configured fans for the radiator? My car has fans on only one side of the radiator.

In my PC I have fans on both sides of the radiator. One fan is pushing air through the radiator and the other is pulling it. This configuration allows for a few degrees cooler than just a single fan on one side of the radiator?

  1. Why do cars not make use of a pump/reservoir combination?

Most computers make use of a reservoir and pump combination as a single unit because it’s generally cheaper. My car has the coolant and power steering pump separate from the reservoir. The pumps are mounted to the side of the engine and driven by the accessory belt. There is very little room to access the pumps. I’m assuming this is designed this way because you need the high RPM of the belt to drive the pump. But why not just get an electric pump that is part of the reservoir that is very simple to replace?

  1. Minimum liquid levels in power steering and coolant?

I really don’t understand this one. In PC cooling you never want to run the pump dry, and want the tubes full of fluid at all times. So in vehicles, how is the minimum fluid level decided for the reservoir? As long as the reservoir is not empty, and the tubes are full of fluid, why does it matter if it’s 1 inch from the bottom or 3?

  1. Why is there no drain valve or plug for power steering systems?

I really am puzzled by this. In PC cooling you always put a drain valve, otherwise removing the fluid is a real pain!

  1. How is flushing bad?

In PC cooling you flush the loop by opening the drain valve and letting out the old fluid, close the valve, add in distilled water. Turn on the pump, then with the pump on, open the drain valve, and then shut it without letting the pump run dry. You then repeat this process until clear water comes out. Is this not how flushing works in cars? What fluid is used as the sacrificial fluid that is flushed through the system. Basically I don’t see how in computer cooling, running fluid through your system and draining it multiple times is bad to the cooling loop. So why is it bad on cars, is it because they use some fluid that has chemicals in it to remove debris. And the concern is that the debris in old cars maybe the only thing preventing leaks, or acting as friction material in the transmission for the rings?

Sorry for the noob questions.

I am fairly computer savvy but never once have needed a liquid cooled computer. Never once needed any of the car stuff of which you speak.

On a car, it is cheaper to put in one big fan than 2 smaller ones. There is mor room in a car and you don’t even need the fan to cool the car when it is moving. cars have gone to two fans, both pullers because of A/C. Compression fittings cannot handle as much pressure which is why it is illegal to repair brake lines with them. Cars are designed to last longer than computers.

As a matter of fact my grandson who has a PHD in computer science said if our cars worked as well as our computers, we would all have gone back to horses.

Cars have reserve capacity for fluids because you don’t want to check them daily and also don’t want them to strand you.

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  1. The fitting you describe is an O-ring fitting, not a compression fitting. Some cars do use O-ring quick-connect fitting rather that barbs.

  2. Some do use pushers and pullers. Depends on the cooling needs, packaging and weight targets.

  3. Again, packaging and weight. Some cars use mechanical water pumps mounted to the engine. Shaking a reservoir is not a smart idea so they are mounted on the body. Some cars use electrical water pumps (not common, yet) that are also not integral with the reservoir because of packaging.

  4. Reservoir volume is always limited by packaging. The max level is determined by thermal expansion leaving enough air space above. The minimum is dictated by maximum cornering, braking forces and fluid de-aeration needs in the power steering pump. For the coolant, you don’t want to uncover any return lines which also may aerate the fluid.

  5. Because fluid changes are not required at all or they are very long intervals. Plus, you can remove the lowest point of the pressure line and it all drains out so why pay the extra cost for a plug? And many cars these days have electrically assisted steering.

  6. Depends on what it is. Flushing brake fluid, coolant is good, same for power steering fluid. Flushing an automatic transmission can be good if it was been properly maintained and the filter changed at least once. Bad if the trans has tons of miles and is acting improperly. Tends to send trash through the working parts clogging up orifices.

Cars are not PCs. Your PC doesn’t roam around in the rain, slush, mud, dust, gravels and general crud of everyday life. It sits in a corner of the room and deals with dust and pet hair.


Thanks for the explanation guys, this helped a lot!