HELP, V6 coolant bleed by garage

[joelverlaan]

Hi!

VIQ: Very Import Question.

About a week ago i had a small hole in the rear heater coolant pipe and my garage advised to buy a whole new pipe, so i did!

But, my garage will be installing the new pipe;
https://mazdabongo.com/product/mazda-bo ... ll-models/

My garage is a Jap import specialist, but not a bongo specialist.
He still thinks his 800+ HP R34 Skyline is faster than my 2.5 v6 bongo, idiot..

So, i doubt he'll bleed the coolant system properly, especially with the rear heater matrix thermostat.

Can i drive home safely? 7-8 miles..

Once i am home, should i drain and do a full refill and bleed proces?
Any other usefull tips, like flushing?

[g8dhe]

There is only one thermostat for the engine, the heating matrices are hot all the time, its the air that flows over the matrix that is controlled and mixed with cool air for the required temperature.
If the coolant is filled using a vacuum system then its probably going to be fine, don't get worried, you can expect the level to drop over the next few heating/cooling cycles as any remaining air escapes so check the level before starting the engine each morning for a couple of days/trips.
The V6 doesn't seem to suffer as badly as the diesel engine with air blocks, whilst it isn't "self-bleeding" as in the 2l version it doesn't seem to be a major problem on filling. However all Bongo's have similar number of pipes and hence the chances of a leak is common for all of them.

[joelverlaan]

Picked up my bongo, garage got about 6-7 liters in..
Drove home and openend up the expension tank.
Together with a lot of air came some coolant (0.5L) out of the tank.

I decided to fill the system up myself using the following method;
Cold motor, expension tank cap off
Hold the bleed pipe higher than the expension tank with a bucket and fill the expension tank untill the expension tank overflowed.
Started the engine, still expension tank cap off.
Keeped topping up the expension tank.
Let the engine idle for 1 min, rev it for about 30 sec at 2500 rpm, idle, rev and so on. Whilst keeping the expension tank full.

Question: "is it normal that coolant runs through the bleed hose when revving the engine, i was holding the bleed hose about 30cm higher than the expension tank?"

In the youtube video this wasn't the case..

I repeated this proces, keeping the expension tank topped up until the bottom hose got hot.
Just to be sure, repeated it with a hot bottom hose for about 10 mins.

After i was done, i drove about 10 miles.

This morning i had to put about 0.5L in the expension tank.

So, have i done it correctly?

I'll keep checking the level after every trip, once the engine is cooled down.

[Bonneville]

I find the trick is in the fill not so much the bleed. The bleed becomes the focus if the fill isn't done carefully as air is trapped from too fast a 'top down' fill.
I start by removing the drivers side engine block hose and filling with funnel until it overflows then put the hose back on the stub. This fills the rear heater matrix, part of the block and the front transit pipes. Then it's round the front to the radiator and fill that slowly. Squeeze hoses at every stage until no more water goes in.
Finally, go to the expansion tank. If you've got it right, barely 2 litres goes in here at this stage because you've filled it already from the bottom up.
Do it like this and bleeding is as per the manual and straightforward.