V6 heating not working after garage work

[ItaBongo]

V6 petrol —— HELP ADVICE ——

Juts got back from a bongo specialist garage after quite a bit of work including new radiator various coolant pipes replacement, cam belt including water pump & new thermostat and more…

While driving back I notice the heating would not work. I cranked the heat all the way to max 32 degrees and set to manual (on the digital control) but is it just comes out cold (maybe style but warm but definitely not hot).

The heating was working before all the work took place. I drove back to the garage and the mechanic said after all the work they fully bleed the system just to run it as it is for now and see how it goes that I s should hopefully change back to normal.

I’m quite a bit scared to be honest

The temp gauge on the dash works and stays at is usual 11 of clock position.

Another thing I’ve noticed the top hose on the rad it’s hot but the bottom isn’t very hot at all

Any suggestions please ?

Is it safe to drive it like that?

Thanks

[gilly99]

Speak to the garage owner/manager, that's definitely not good advice from the mechanic. It's likely air-locked and needs fully bleeding.

If a diesel, I would definitely not drive it. Think the petrols are more forgiving, but it needs bleeding properly for sure.

[g8dhe]

Get back to the garage, either a coolant flow (bleeding problem) or depending on what work was done precisely the control rods that adjust the flaps in the air box in the leg areas either side are not working. Does the temperature gauge show the normal reading 11 Oclock position ?

[ItaBongo]

Yes gauge shows 11 of clock position

The heating matrix on the pax side footwell I found the bottom hose it’s hot however the top it’s not.

I asked for a flush to be undertaken while the vehicle was with them which they did and change me for, however it seems the flush has done the opposite - block the heating matrix/ garage now asking for another £100 to perform new flush and £40+ labour to fit a new heating matrix

From a customer point of view very unhappy and find it so anti business after I gave them £2.5K for varies work had expect the vehicle to perform better and no worse.

But hey we live & learn power of social media I guess will do the rest and I’ll find another garage to spend my money.

[g8dhe]

The problem with a simple flush of the entire system is that any deposits that get washed off the inside of the hoses has a habit of blocking the very small cores in the heating matrix. If you search thru the forum most people recommend disconnecting as many pipes as possible and then flushing and reverse flushing each component in turn. There is an excellent series of articles below on the coolant system;
Basic fan operation https://www.igmaynard.co.uk/bongo/forum ... =3&t=48872
Cooling system diagram https://www.igmaynard.co.uk/bongo/forum ... =3&t=35902
coolant flow - (follow up to cooling diagram) https://www.igmaynard.co.uk/bongo/forum ... =3&t=36433
Pipe - expansion tank to heater circuit return https://www.igmaynard.co.uk/bongo/forum ... =3&t=49505
Mazda thermostat - A few observations https://www.igmaynard.co.uk/bongo/forum ... =3&t=39193
Water pump - opinions please https://www.igmaynard.co.uk/bongo/forum ... =3&t=47381
There quite long but worth a read if you want to understand the entire system or just even various parts of it
Like the front heater matrix repair http://www.g8dhe.net/bongo_images/Paul_ ... placement/

[ItaBongo]

Hi Geoff

That’s so very useful, thanks son much !

Are you a V6 owner too?

I should read on all the articles you have sent

Is it normal for the bottom rad hose to be cold (or very little warm) after engine been ruining for about 1 hour (mix driving & stationary) ? The garage advised that after they replaced various hoses & rad this is normal as the system itself doing what it should do and the bottom hose shouldn’t be hot hot anyway.

They replaced water pump & thermostat too as part of the cam belt change

Initially I thought the thermostat was not working correctly, is there a way of telling if thermostat is working as it should without taking it out ? The gauge on the dash starts a 0 (cold) when I start the engine then gradually raised to 11 of clock position and after all the driving yesterday (around 1 hour and half) it stayed there no movement.

The heating seem to work better (warmer air) when vehicle is stationary but then it get colder again a soon as I start driving.

Thanks again for the help & support

Very much appreciated

[g8dhe]

The bottom hose will be the coolest part of the system! The hot coolant comes out of the engine and then splits into several routes.
One is back to the engine (smallest pipe) via the thermostat top inlet (this gets sealed if the thermostat fully opens up).
Second is via the various heating matrices then back via the de-gassing tank (the highest part of the system in front of passenger), this then has a feed back to the thermostat control port to allow thermostat to sense the actual temperature of the coolant itself just before it enters the engine.
The final route is via the top of the radiator and down thru the radiator to allow cooling of the coolant, from the bottom of the radiator it feeds back to the thermostat from the bottom so that when the thermostat opens up the coolest coolant is allowed into the engine itself.
The diagram below is for the diesel engine, but the same basic setup is used for the petrol engines, but the locations are a little different;

The exact temperature at the bottom of the radiator will vary depending on air temperature, engine workload etc. but it will be the coolest. During winter it might not even get "warm" depending on just how hard the engine is working and how much heating of the aircon system is required! Click the image below to see the animation of how the the coolant is controlled by the thermostat

Bear in mind that the Bongo has a SEALED and PRESSURISED cooling system. There is no "top-up" tank which is used to maintain the correct level, as its sealed! Also its PRESSURISED by the expansion of the hot water, this is so that greater amounts of heat can taken away to the radiator more effectively, lots of European cars are not sealed and and pressurised. This means that any leaks in the system can be a PROBLEM as then the pressure drops, heat removal is affected, and it can lead to rapid over heating, the rest of the time it leads to better heat management of the engine than can be achieved with open unpressurised systems ....

[ItaBongo]

Wow so much details there

You’re not local to Leeds by any chance to have a look at my bongo ?

[g8dhe]

No, down on the South Coast and I employ a garage to work on my V6! You won't get me under the bonnet unless its for electrical or photographs

[ItaBongo]

Ahaha don’t blame you!

Seriously thank you for all the infos & support