Miata water pump

[Janis]

So this is the moment You will hear my accent

Am helping to my friend to solve coolant leaking issue on his Miata.

Am not sure what exactly was the problem :
-leaking gasket (it was hard and and fragile)
-or leak somewhere from shaft seals
-or both

there is no play in the shaft

Also is that gap ok between impeller and body? ~1,5mm

And what for are these holes that I am talking about in video?

 

[ng_randolph]

The hole is to allow any coolant that makes it past the shaft seal to weep out and not get into the bearing. Most (all?) water pumps have this weep hole.

 

[Dr.Jeff]

As Bjorn said, the hole allows any leaks a place to go. So if the pump was leaking from there it means the seal is worn. The gap you asked about usually isn't as important as the gap on the other side of the impeller (blades), between the impeller and the housing it fits into (engine side). The smaller the gap is on the housing side, the less water can travel around the impeller instead of through it. So a smaller gap works better.
Since the pump is already off it is probibly best to install a new one either way.

 

[Janis]

Also on Miata to take off waterpump, timing belt has to be removed first.

Timing belt is one year and 4000km old, should in this case timing belt be replaced also?

 

[Dr.Jeff]

That's not many miles and it's not too old, so I'd only replace if it isn't too expensive. If they are cheap price and depending on his budget, then sure why not - a new one is good insurance. But not necessary; it doesn't sound like he drives it too much (4000 K in a year), so it should be good for a few more years. However if he can't do his own service work and would pay a lot of money to have someone change it for him later, then it might be cheaper to go ahead and do it now (since you work for free ).

 

[Janis]

haha
I'll give him this advice, that what he won't change now, will have to change later for some good amount of money

Thank You all