In this episode of Forecourt Fixes we guide you through a few of the checks and topping up
points you'll find under the bonnet of your car.
Some things, such as the brake fluid, you will probably never need to top up....
Whereas other reservoirs, like the windscreen washer tank, you will need to refill
But firstly, how do you get the bonnet open??
We all know that cars have become far more complex in the last 10 years or so and nowhere is
that more apparent than under the bonnet which now seems to be an extremely tightly packaged arrangement of wires,
pipes, plastic bits of shrouding and more and more components.
So you've given up already? Shame on you! Don't be daunted.
While it IS all very complex and tightly packaged under there, the car makers are very well
aware that regular maintenance of key items is absolutely critical to the safe running of your car and, of course,
to your long term customer satisfaction, so everything that you need to deal with in a regular check on the
forecourt or on your drive will be clearly marked.
While the layout under the bonnets of a range of cars might seem very different, they will each
contain all of the same components, and things that you need to check regularly that are clearly marked.
There is a set of internationally agreed symbols which will show you exactly what goes where and
having read your manufacturer's handbook... You haven't?... You will recognise all of the necessary check and fill
All of the car breakdown organisations agree that up to half of all the millions of breakdowns
are caused by a lack of the simplest maintenance and servicing. That's tens of thousands of easily preventable car
Before we start, a few important safety issues. Always, always, before looking under the bonnet.
Car in neutral, handbrake on, ignition off. Ideally take the keys out. Then it is safe to check under the bonnet.
Remember it's a piece of complex machinery. There's moving belts, whirring fans, rotating parts, hot fluids and
boiling water so be careful.
Another thing to be aware of, if you are wearing a tie, a scarf, a long necklace, in fact
anything that could dangle into the engine bay, either take them off temporarily or tuck them into your
If you are carrying out a brief under-bonnet service at home then it's safest and therefore best
to do so with the engine cold.
If, however, like us, you are doing the under bonnet on a forecourt that you've just driven to,
everything's going to be warm for quite a long time. It's best to take five minutes or so... Go and grab a cup of
If you ARE on a forecourt, and remember this is Forecourt Fixes, please do consider other
customers uses of the forecourt and move your car, while you're doing the checks, to somewhere which is tucked out
of the way. Other drivers and forecourt staff will thank you for your consideration.
But first things first. Exactly how do you even get the bonnet open?
On most cars the release lever is clearly marked with a pictogram of an open bonnet and it is
located in either the driver's or passenger's footwell. If it isn't obvious check your car's handbook and it will
show you where to look.
Some manufacturers follow a slightly different pattern though. In this particular instance it's
key locked at the front and there are other variations, so do check your manual.
When you pull the lever the bonnet will only open a little so how do you get it fully open?
As a safety feature, to stop the bonnet accidentally flying open whilst driving, there is always
a secondary catch which you need to unlatch to open the bonnet. Each car is different, but this is usually a small
lever in the dead centre of the opening and easily felt for.
A lot of bonnets these days are then held up by a hydraulic strut. Some simpler designs use a
wire rod that you need to carefully put into a shaped slot to stop the bonnet collapsing on your head.
So, now you're in! Like some intrepid explorer you've reached the centre of your car's universe.
Now is the time to take stock of what is where.
As we said, every car is different but most, regardless of whether they are front, rear or 4
wheel drive, are very similar.
In each car you will find coolant, brake and power steering fluids, windscreen washer reservoirs
the oil filler cap and dipstick, the battery, fuses, and a whole lot more. We will cover each item in more detail
in separate videos, but for now, here is a brief overview of what is what.
In modern cars, many system parts are covered in shrouding, or hidden behind plastic panels, so,
remember, you can check your car handbook for the exact location of each item on YOUR car.
On the top of the engine, roughly in the centre, will be the oil filler cap, a large plastic cap
which will usually have an "oil can" pictogram, and "Engine Oil" or similar shown on it. Sometimes the manufacturer
will helpfully put the correct oil type on it for you too. Before you randomly add some oil, you'll need to see
whether the engine actually needs a top up. To check this you use the Oil dipstick, a thin piece of metal that
literally gets dipped into the oil to see how deep it is at the bottom of the engine. The dipstick has the minimum
and maximum oil levels engraved on it, and it is between these levels that your oil should be. This is OK.
Remember, your engine must have been turned off and stationary for at least 5 minutes, to allow
the oil to settle. The dipstick can then give you an accurate reading.
Usually near the rear of the engine bay will be the brake fluid reservoir, a clear plastic
reservoir again with a large, labelled, plastic cap. The desired level will be marked on the side.
Another expansion tank or reservoir holds the engine's coolant, the mix of water and anti-freeze
that is pumped round the engine to stop it from overheating. Of course, this means that it can and does get very
hot, and it should be treated with caution.
Again there will be a clearly marked level and a large plastic cap which must be removed to top
up. NEVER remove this cap until the engine has properly cooled as it could cause pressurised boiling hot fluid to
shoot out. A good tip is to only open it, with caution, wrapped in a old rag you keep under the bonnet for this
Usually near this is the power steering fluid reservoir. Again it is often a clear plastic with
the level clearly marked but sometimes there is a small dipstick with the min/max levels shown on it.
One fluid that you will regularly need to top up or refill, particularly in the winter when the
roads are salted or gritted, is the windscreen washer fluid. This filling point is usually clearly marked with a
windscreen spray pictogram on a blue cover cap. The exact levels of this might not need to be quite so precise when
it comes to filling, but you certainly don't want to run out at the wrong time. It is worth noting that the actual
tank for holding the washer fluid can be quite large and well hidden in the depths of the engine bay or even in the
Before we finish our tour, it is perhaps worth pointing out a final few items.
The car battery, the power we rely upon to get us started on cold winter mornings, is here.
Manufacturers often cover these up to protect them from water or other harm.
Access to the headlight bulbs is usually through the engine bay. And, the air intake box and its
filter are in this part of all of this ducting, here...
So that concludes our brief tour of the engine bay and all of the main service points. To find
out more about each item, and how to check and top them up, we have made separate, detailed, Forecourt Fixes videos
about them all.
Before we go, make sure that the bonnet is fully and securely closed before driving off the
forecourt. Gently try to lift it and if you can't do so then it is properly locked. Even if someone else has been
working under the bonnet on your car ALWAYS check that it is secure before driving off.