Cooling system Part 2

There are several components in the cooling system and they all have important job.

The water pump circulates the coolant around the engine. It works in small and in the large circle the same. It is driven by a V-belt or a timing belt. Without it the coolant would still circulate but not as quickly and then the liquid would heat up to higher temperature and overheating of the engine could occur.

Modern radiators are made from aluminium. Coolant enters at the top right after it comes out of the engine and then travels though thin pipes to the bottom (or from side to side, then it is called cross-flow). All the way through it is cooled down. The heat is transferred from coolant to the pipes, from pipes to the aluminium fins and then it is radiated to the air. At the end of this process the coolant is ready to enter the engine all over again.

The fan takes care of air exchange in the radiator. It is equipped with shrouds which make sure new air is sucked in and the fan doesn't only circulate the same air. Earlier fans were drive by the V-belt, that's why they are still sometime called fan belts. But now it's usually electronically operated which has advantage over belt driven fan - it works only when it needs to and it doesn't use engine power to do so. When a vehicle flies through a motorway, new air doesn't need any help to get in. But if the car is stuck in the heavy traffic or just going slowly through a city on warm day, the air may need some help and in that moment fan gets in charge.

As one of the cooling system's job is to heat up the engine after start as soon as possible, a thermostat is used for this reason. It is valve which opens at predetermined temperature. Until then it stays closed, preventing the coolant to go the radiator. The coolant keeps circulate around the engine (what I call small circle) and warms up much faster. When that happens, the wax inside the thermostat starts to melt, valve opens and let the coolant to get through to the radiator and starting the large circle. In other words the operation depends on changes in volume of the wax around the melting point, the pressure becomes so great that it forces against a spring inside. When it is time for thermostat to close again, the spring returns the valve on its original place and closes the passage.

Cooling system Part 1

When I started with the cooling system, I had no idea how important it really was. But the temperature of the engine must be controlled all the time. If it isn’t then the combustion chamber walls, piston crown, upper part of the cylinder, valves can expand and change shape. Detonation (mixture of fuel and air starts to burn in more places at once) or preignition (the mixture self-ignites before the spark plug can create a spark) can occur. However, over cooled engine can cause many problems as well. It can reduce vaporising of the fuel in compression stroke and creates deposits on cylinder walls which will dilute the oil and destroy its lubricating properties. Or water vapour formed during combustion will form sludge with the oil and then corrode the engine parts.

Nowadays is used water-cooling instead of the air-cooling because it is much easier to control the temperature. But the engine operating temperature is around 90°C which is quite close to the boiling temperature. To prevent water from boiling, ethylene glycol is added which increases the boiling temperature and lowers the freezing temperature as well. But that is not all, when the car is running the coolant is kept under pressure and for every 4kN/m2 the boiling temperature is raised by 1°C. Another thing that is necessary to put into the coolant, before it is used in car, are rust, corrosion and foaming inhibitors. Because as we all know metal and water on its own is not an ideal combination.

The coolant is circulating around engine all the time, either in small or large circle (that is what I call it and will explain later). If it wasn’t, localised overheating would become a serious problem.

Recently I discovered that the warning on the cap of the reservoir is not only about our safety. You should never open the cap when the engine is still hot. That is not only because the coolant can come out and cause serious damage to you or somebody around you but also because the moment the cap is opened the system lose its pressurised state. It will try to equalise to the atmospheric pressure everywhere around and it can start to boil immediately which will destroy the hoses in the system.

The cooling system itself has more than only one job:

- it needs to heat up the engine and bring it to the operating temperature as soon as possible

- it needs to maintain the temperature at all costs

- and then it has to remove surplus heat from the engine

Against the odds

Even though I am really caught up in these car things, even though the more I learn the more I want, the more I know the more I am fascinated by all of it. There is still one section that I scares me as hell – the electronics. My physics in high school wasn’t great and the teacher didn’t excel either. So my current knowledge about automotive electrics is…well, I know there are conductors, insulators and semi-conductors, I know that electrical current depends on electron exchange and I know that there are series, parallel or series-parallel circuits. I know something about computer programming and I suppose ECU in a car works on a same basic principle. But that is not as helpful as it may sound. And that is where my knowledge end.

Every time I tried to read something I didn’t get very far. It makes me want to sream but while I was reading I just didn’t understand a word. You know, my boss keeps telling me that electronics is the best way to go, especially for me as I will never be strong enough to carry out some of the work in mechanics and that the best thing to do is to use my brain instead of the strengh I don’t have and never will. And he is right, not only because what he says is absolutely true but also because every new car model uses more electronics that the previous. What if in thirty years there will be not petrol or diesel cars. What if there will be only hybrids, electronic cars and other alternatively powered vehicles. My knowledge about the internal combustion engines will be simply useless.

So I made the electronics my goal. I don’t care how many attemps I will need, how many books I will need to read before I understand anything. Eventually I will make it because if I can make myself understand it, become an automotive electrician and be good at it, then there is nothing that can really stop me, is there? Because by this I would just achieve something impossible.

The one and only

As I already mentioned before I love to read, it‘s not only fiction anymore but also books about cars which I enjoy even more. There is one book which I absolutely adore - Auto Fundamentals. It starts with the basics. It helps you understand how an engine works even when you don’t know the first things about it. And then it continues into more complicated issues and secrets of car systems.

I haven‘t finished this book yet but I made it through about 200pages. There is just so much to learn that it is impossible to catch all of it on first attempt. It tells you what each part does, what makes it run and what can go wrong with it. It will show you how fascinating the car universe really is. 

There is also a workbook available but I don’t consider it to be necessary or particularly helpful. It is a good practise but the textbook is enough itself.

I am putting here a list of some other books I own a value but Auto Fundamentals will probably stay my sweetheart for some time.

Auto Repair for Dummies – Deanna Sclar

Internal Combustion Engine Fundamentals – John Heywood

Intelligent Vehicle Technologies: Theory and Applications – L. Vlacic, M. Parent, F. Harashima

Automotive Battery Technology – Alexander Thaler

Advanced Automotive Fault Diagnosis – Tom Denton

How Cars Work – Tom Newton

Toubleshooting and Repair of Diesel Engines - Paul Dempsey

Auto Fundamentals – M. W. Stockel, M. T. Stockel, C. Johanson

Idiot's Guides: Auto Repair and Mantenance - Dave Stribling

Back to school

After I left university I didn’t think I would ever have to go back. I didn’t wanted to go back. But even I knew I needed to study to be a good mechanic one day. And so I started on my own. With wikipedia and other websites I slowly started to discover whole new universe of knowledge. Crankshaft and camshaft were the first parts I learned about. Part by part, a little bit every day after I got home from work. Soon I started collecting books. From the simplest one like Auto Repair for Dummies written by Deanna Sclar to Advanced Automotive Fault Diagnosis by Tom Denton (not exactly a cheap reading the second one). I have always loved reading but until then those books were fantasy or sci-fi. Once I started the first book about car I found out it‘s not that different. I read because I was interested in what I was reading and that time I just learned something more while doing that, nothing else really changed. Yeah, my brother told me that if I wasn’t such a geek already, something like this wouldn’t be possible.

So I studied every day just an hour or two and I really enjoyed it. If we had a job at work the next day, I prepared for it. But it wasn’t quite enough. Well, for me it was, but if I wanted to get my qualification in Auto repair and maintenance the only way to do that was to attend school. We were trying to find another way but there just wasn’t any. None of the providers were suitable. And even my signing up wasn’t without complications. You know, the whole not-being-English thing but also apprentices earn £3.50 and how the hell was I suppose to pay for school when I had to pay rent, food and other things. Well yeah, apprentices usually still live with they parents so they don’t have to worry about this but not always. What if they live on their own and don’t have daddy to pay for all the expenses.

Anyway I managed, I am still alive and I am a student. I was actually quite excited on my first day. I skipped level 1 and they put me directly in level 2. I was a little bit scared that I will be behind with my knowledge. I had been studying on my own only two months before my first day.

I can’t remember the last time I was so disappointed. The teacher asked what did it mean the four stroke engine and what were the strokes. I was quiet but so was everybody else. I wasn’t going to answer, it was my first day and I was really insecure and I was the newest in class whereas others already knew each other for four months. I thought he was joking but he was deadly serious. I still can’t believe nobody knew the answer. Then the teacher asked about the difference between the petrol and diesel engine and it was quiet again!!! This time I raised my hand, I was not going to be just a quiet new girl when I knew the answer. Come people, it is the first thing every mechanic needs to know, isn’t it? Then even the teacher was surprised that I knew that 14.7 is stochiometric fuel-air ratio and what did it mean. And so he asked me how I knew it. ‘I’ve been studying a little bit on my own,‘ was my answer. And right after I spoke everybody looked at me like I was some kind of an alien, not kidding.

That is why I was so disappointed, I just couldn’t believe that after only two months even the teacher was surprised by my knowledge. Especially when I had a feeling that I didn’t know anything. And the more I knew, I realised how little I knew. I couldn’t believe that was suppose to be level 2. What on earth were they teaching in level 1?

Few years ago I came across a quote by a writer Mark Twain - “I never let schooling interfere with my education“. I have always loved that quote but after my first day in Stockport College I realised that if I wanted to learn anything at all, I would just have to do it myself.

P.S. I fell in love with the school library. I am just worried that I won’t have enough time to read all of those books.

My first day

I still remember my first day. How excited I was and scared. I remember telling myself ‘whatever happens do not let them find out, you don’t know the first thing about cars‘. I didn’t even have any working clothes so I put on the only pair of jeans I onwed (even I knew that working in leggins wasn’t such a great idea).

And so I met Alex – my teacher mechanic. He was just working on nearside wishbone when I got there. Not that I had any idea what wishbone was back then. Later we changed anti-roll bar on another car and that was my word of the day – anti-roll bar. I spent my first day learning the names of different tools which was not easy as I didn’t have any idea how those things are called in my language, not to mention in English. At the end of the day I managed to remember what grease means.

I got to take out few screws. Not an easy task for someone who didn’t know which way was opening and which way was closing. And ratchet? It took me several days to understand it and even after that it was less difficult to remember that if the flap was pointing left the ratchet would open the bolt. I know, I know…but it’s not funny. I just had no need to learn these things before as I have never had to get my hands dirty. Before this garage I worked in a car wash which was hard work but not dirty work. And I have never had to use these skills home. And I am a girl, girls don’t have to know this so stop laughing.

Nika the Car Girl

I became an apprentice about five months ago. Right after I left school to be a mechanic. I studied Mechanical Engineering in university and I stayed exactly one month. The only girl in class with twenty five guys. Sounds good, right? But I was sooooo bored. Don't get me wrong I was interested in the topic but I just hate sitting in the class and listening to the teacher. I just wanted to create something, to fix something not just fill my notebooks with numbers and words all day long. Not that my parents understood (kind of a funny story but lets leave that for another time).

Well, anyway I started to look for an apprenticeship. Wasn't as easy as it sounds. I applied online, I visited this office in the city which was supposed to help young people with finding apprenticeships. Wasn't really enough. The answer was usually 'you don't meet our requirements to become an apprentice'. Yeah, right, I bet what they really meant was 'we don't want a girl in the garage because you will never last anyway'. Maybe not all of them because I didn't know much about cars especially from the practical part but I really wanted to learn. But on my defence I have never got the chance to do the practical things. My dad’s knowledge don’t go further than adding coolant to the maximum and my grandfather bought Renault Megane because it looked nice. So you can imagine why I didn’t have any experience.

Then I got angry, it wasn’t fair that they didn’t want to accept me just because I was not English or a boy. I stopped waiting for the opportunity and just made one for myself. I walked around the garages close by and asked. Oh you should have seen the expression in the faces of some of those mechanics. But then I finally found one where they didn’t care and were in need of an apprentice.

And then Nika the Car Girl started living her dream.