"modern" Coolant Systems

[Masekwm 2]

I'm not the most knowledgeable people when it comes to car mechanics, however, a few years of owning 205s and a Ka has led me to know how to swap wishbones, coolant valves, etc.

 

Today our little Mazda had no water in the wiper fluid so I opened the bonnet and saw very little that looked 205/Ka like. A litre of fluid later, I stood and looked round.

 

A weird brake system, weird gearbox but the radiator coolant confused me. Without trying, it looked like it was quite simple to open the expansion tank and add fluid, the lid is like the 205 washer bottle. There is another on the radiator that looks like the expansion tank lid on the 205.

 

So how does this work, and why doesn't it just blow off the other weaker cap?

[davey sprocket 14]

I'm not the most knowledgeable people when it comes to car mechanics, however, a few years of owning 205s and a Ka has led me to know how to swap wishbones, coolant valves, etc.

 

Today our little Mazda had no water in the wiper fluid so I opened the bonnet and saw very little that looked 205/Ka like. A litre of fluid later, I stood and looked round.

 

A weird brake system, weird gearbox but the radiator coolant confused me. Without trying, it looked like it was quite simple to open the expansion tank and add fluid, the lid is like the 205 washer bottle. There is another on the radiator that looks like the expansion tank lid on the 205.

 

So how does this work, and why doesn't it just blow off the other weaker cap?

 

 

Is it a radiator to cool the weird gearbox that doesn't need to be pressurised?

[welshpug 1,622]

a lot of Jap cooling systems work like that, never got my head round how they actually work as it didn't bother me enough to ask

[Masekwm 2]

a lot of Jap cooling systems work like that, never got my head round how they actually work as it didn't bother me enough to ask

 

I didn't know it was Japanese until after we bought it, I thought it was a fake Fiesta

 

Is it a radiator to cool the weird gearbox that doesn't need to be pressurised?

 

Don't get me started with the weird gearbox, all looked normal until I saw the top and then I got confused. The brake system is also rather weird and there is nipples everywhere. I guess this is just modern rather than what I'm used to.

 

Loads of room though and hiding the washer bottle in the bumper is rather well thought out.

[Rippthrough 98]

They're pretty much self bleeding when done that way, the other tank is just a header tank that lets any excess air bubbles out and keeps a reserve of coolant.

[Sandy 189]

The main rad cap opens both ways, suck and blow if you like. The little top up tank is a reservoir for the system and isn't pressurised. Because the rad cap neck is connected to the little tank at the bottom, it can only suck or blow coolant.

 

Most systems rely on the coolant bypassing the stat to get hot water to the stat. I had alot of problems initially with my Honda engine'd 309 boiloing, while the stat was cold. I didn't have the bypass plumbed right, so the stat never saw hot enough water to open. Seems obvious now, but perplexed me at the time! All the new generation Ford (aka Mazda) engines run two way stats that need the right hot/cold feeds to work properly. It can make for headaches in aftermarket or custom installations and alot of people just junk the stats to get around it.

I'm not a fan of running without a stat in any car. Having the engine at a stable temperature gives more consistent performance, reduces wear and makes it much much much easier to map accurately!!