Maintenance questions?

2013 Mazda 5 100k

When or how often to change these:

  • Coolant (modern fluid) - is it enough to use a hydrometer and if it passes, keep the coolant without changing?
  • fuel filter
  • thermostat
  • water pump
  • PCV

I never change the fuel filter,thermostat and water pump unless there is something wrong with them.Even the pcv valve unless its throwing a code.Coolant should be change according to your car’s maintenance schedule.

The owner’s manual should specify some of those. Coolant is generally 100k miles or 5 years on the newer cars, although Mazda may be different.

The fuel filter might not be serviceable. Many cars now have the filter or strainer as part of the fuel pump assembly. If the filter is serviceable, I would think the owners manual might specify a replacement interval.

The manual won’t specify on the thermostat. I generally change it when changing coolant or if I have to drain the coolant for some other repair (water pump, etc). Or if the thermostat sticks open or closed, of course.

Water pumps generally aren’t changed unless they are going bad (leaking from weep hole, bearing play is found) on the cars with a timing chain. If the car has a timing belt, the water pump can be replaced during the scheduled timing belt replacement, which should be in the owners manual.

PCV- not sure. Many cars now have a “fixed orifice” rather than a pcv valve that can be changed. I’ve changed them on my cars in the past, but honestly I think it’s a waste to change them if the check valve inside still rattles when you shake the valve or unless you’re changing it in an attempt to track down an oil burning issue or something. Maybe change it at 100k miles? I don’t know. I’ve never had a pcv valve caused problem or a pcv valve failure.

Coolant. If the coolant is clear, it is still OK. If it is even the slightest bit cloudy, the corrosion inhibitors are used up. If it is a muddy brown, there is damage in your cooling system. But at 6 years old, even if it is clear today, it could turn cloudy and them muddy in the near future. You would have to check it every day to be sure you don’t do any damage.

Once it turns cloudy, you will need to do the maintenance very quickly and probably not on your terms. The safe bet is to do a drain and refill now and do not do a flush. Cheap insurance. If it is muddy, you have to do a flush.

Fuel filter. Never had to do one, but people I know that have had a Mazda have had to change them, don’t know why.

Thermostat. You don’t need to unless there is a problem. As thermostats get older, they tend to not fully close

I change my thermostat when I replace the radiator, that with the cap and all the hoses. Just did that in my car not to long ago, when this timing belt gets replaced next time then I will do the water pump. Dont think i have ever touched the PCV I dont think I ever touched and it is a 21 year old car.

  • Coolant (modern fluid) - is it enough to use a hydrometer and if it passes, keep the coolant without changing?
    I might go 10 years,
  • fuel filter
    Do mine every 30k
  • thermostat
    as needed
  • water pump
    As needed
  • PCV
    Mine does not have one but if it rattles it is good from my experience
    Don’t forget air filter and timing belt if so equipped.

I use the “Cheap and Easy” metric.
If “Cheap and Easy” or part failure would lead to expensive repair, do as preventative maintenance.
If not wait until failure.

Coolant - “Cheap and easy”
Fuel filter - Some “Cheap and Easy”, others are not. Check for your car.
Thermostat - See above
Water Pump - Not Cheap or Easy and if it fails the potential damage could be very expensive. Plan on replacing around 100K good or bad.
PCV - “Cheap and Easy”

Other “Cheap and Easy” (replace on a regular schedule) includes:
Oil Changes
Radiator Hoses
Sepentine Belts
Brake Pads
Air Filter
Light Bulbs

Keep up with maintenance, regularly wash and wax and most cars will easily run great well over 100K

----- Coolant (modern fluid) - is it enough to use a hydrometer and if it passes, keep the coolant without changing?

I tend to be bad about this. 5 + years and it still looks good. I will add a bottle of water pump lube at 5 years to replenish the additive package. But If it has to come out, it doesn’t go back in.

I do fuel filters at 50K IF they have one.

Thermostat only gets changed if the engine doesn’t heat up quickly.

Water pump only when I see it leaking unless the car is known for bad water pumps or if a pump is run by the timing belt or chain.

PCV, only if it throws a code.

Thanks indeed - what about Brake Fluid flush?
How often?

Every 3 years minimum for a brake fluid flush or whenever you tester shows 3 % or more.

A coolant hydrometer only reflects the freeze point of the coolant.

It doesn’t reflect the condition of the corrosion inhibitors in the coolant.


1 Like

When would u change Coolant and Flush brake fluid if u have 2013 Mazda 5?

That was not my quote, as I posted the questions and responded to them saying

Brake fluid flush when brakes need to be serviced has been my mo.

Most coolants today last 100,000 miles.

The brake fluid is serviced when this tool indicates it should be done.


Mazda has a great site with owner info lookup, took me under 1 minute:

The layout is similar to what Subaru is using, much better than the one having one page for each predefined mileage/age:


The same as any other brand , so it does not matter if you ( not u ) have a Mazda 2-3-4-5-6-or 7.

Caveat: You still need to use the hydrometer because if you fill your radiator with pure water, it will be clear, but you will regret it when it drops below freezing. The hydrometer will verify that you have the correct antifreeze/water mix.

For “Coolant” it just says inspect - what good is it?

On the posted schedule sheet it says ( Engine Coolant ) FL 22 200000 KM or 10 years - other every 40000 KM.

Why are you making this so difficult ? Just have the coolant and brake fluid changed and be done with it.


Inspect your radiator, hoses, pump weeping hole!

For coolant, I read replace-replace-replace!


Do you have “R22” sticker on the coolant tank?
If not, you are badly overdue for replacements.