Design Fault

[roofraisers]

The league is irelivent, questioning is relivent.
What I'm trying to get to is the fact that the efficiency of the system negates the full use of the radiator for usual use.

I agree that in our climate the Bongo radiator may be a little large, but the Bongo was designed to drive in Japan where the climate can be hotter!
Vehicle manufacturers can't put specific sizes radiators in a vehicle for each country of use... it's uneconomical & if the country had an unusally hot spell, all the vehicles would be under cooled & so they would all over heat.

Am I banging my head against a brick wall with this topic? Aint blocked rads a problem with Bongo's?

Blocked radiators can be a problem on any motor vehicle. As I've said before & said by widdowson2008 this is generally a result of poor maintenance.

If you think a 10 yr life is ok that's fine, manufactures are more than happy with that.
I prefer to keep older vehicles on the road and it is only by looking at the problems that stopped them running we can keep them running.

I too like to run older vehicles, but if their previous owners have neglected the maintenance, you have to restore the problems and make good the damage that has occured.

As I've said before "Once sediment is in your system you have to physically remove it."

There are ways to do this.
Removing components & flushing out all the crud from all the various low lying places & dead water areas in the cooling sysyem. The more time you spend doing it, the better the job will be.
Only once this process has been done, you could look at fitting of a filter into the coolant sysyem. There are different types, some are basic gauze filters that fit inline on the top radiator hose & others are "spin on" with more complex hose & filter housing arrangements.
You pays your money & takes your choice.

I've attached some pictures of the different systems, hopefully you will get the gist as I reckon this is probably a whole new concept to most people.

http://autocoolantfilter.com/
http://www.youtube.com/watch?v=1GVIbOnttUg
http://www.commercialfilters.co.uk/waterfilter.php

I am trying to help the discussion - I think that using faster/different coolant flows does not clear sediment build up & you have to prevent it occurring in the first place instead. If sediment has built up, it has to be physically removed & not just continually moved around the coolant system, as the sediment will still cause a problem somewhere else.

Nigel

[widdowson2008]

Total sense Nigel

[The Great Pretender]

Shame, the thread started ok, got some agreement on what was happening in the radiator then it ended up on how to maintain the system.

As the Bongo rarely runs with the stat fully open allowing full flow through the rad this can cause problems.
This in my mind it is a design fault as it creates a dead area.

This happens from day 1 of the Bongo's life. Any micro particles in the system will when reaching the rad inlet start to drop out
as this is a low speed high pressure and volume part of the system. It's possible these will slowly attach to the cores over time reducing that part of the radiators cooling capabilities if not blocking them.
The fact that it has lasted over ten years is irelivent. The problem started on day 1 due to the Bongo's efficient system and rad design. If the rad was in full flow often as in most normal vehicles there would be a constant flushing of the cores and tanks keeping any micro particles in suspension capable of draining out when changing the coolant.

A crossflow rad with bottom main connections may have offered a solution removing the dead area.

As I said before Nigel I don't agree with everything you said and don't want to get into a discussion about it. There are lots of people who accept what is said on here is right as they are not technically minded so I have to respond to your comments about differing rad sizes and temp in Japan.

"The radiator is a heat exchanger. It's purpose is to remove heat from the engine coolant to the outside ambient air temperature as efficiently as possible. As stated above,in a cold climate you would get away with a smaller sized radaitor on a Bongo than you would in a hot climate."

As the rad is rarely in full flow the same design would give the same problems.

"Flow through the radiator is greatest when the ambient air temperature is at it's highest."

Now I know the Bongo is a wonder but what sensor does the coolant system use to monitor air temp and how does it open the thermostat to allow full flow?

Ambient average temperature in Japan (max summer min winter)
Sendia 27.9/-2.0
Tokyo 30.8/2.1
Nagasaki 31.3/3.6

Source Japan meteorological agency.

So 31 to -2, sounds very similar to what we have.

The reason I started this topic was to hopefully get some stand back and think out of the box responses. O well I suppose I would be better of watching p*rn.

[Northern Bongolow]

dont get bitter mel . you have the advantage of spending your whole working life working in this field,to some of us its black magic .it takes time and sometimes a great deal of persuation to convert those that understand, and even longer for those that dont like me.

we have had loads of good chats face to face and pm's,and i still think you practice the black art at times, i for one am just plain scared of upsetting my bongo when its running well.

keep trying to convert us mel, i for one will always listen, i may not understand, but i will listen.
plus p*rn is bad for your eyesight.

thanks for quoting my spelling mistake

[The Great Pretender]

dont get bitter mel . you have the advantage of spending your whole working life working in this field,to some of us its black magic .it takes time and sometimes a great deal of presuation to convert those that understand, and even longer for those that dont like me.

we have had loads of good chats face to face and pm's,and i still think you practice the black art at times, i for one am just plain scared of upsetting my bongo when its running well.

keep trying to convert us mel, i for one will always listen, i may not understand, but i will listen.
plus p*rn is bad for your eyesight.

Aint bitter mate, just sad that those who could move this forward are happier staying in their comfort zone.

[helen&tony]

Hi
Mel....
You're right about the temperatures in japan....similar to Britain, on average, as I've spent 1/2 hour ploughing through records on the internet...and the Japanese Met. Office shows around +30C on a good year, and nowhere near as cold as Scotland!!!!...so, to all intents and purposes the Bongo system in the UK gets the same workout. Maximum Recorded High Temperature in Japan , however, is +40.9C. and the lowest Minimum Recorded Temperature is -41.0C............similar to the Max. here, at +45.2, and -38.3....However, we normally range between +40, and minus 23 C...current high yesterday + 38C
Bongo cooling system is , I agree 100%, perfectly fine in operation...and winter / early spring, the lower half of the rad doesn't work at all...no need to...The bottom hose is still below freezing at 54 Km on a run averaging 50KPH....Summer the bottom hose reads + 41/ 42C. Water jacket below head: Winter: around 60/ 65, summer :70/ 75....water exiting head: (measured in the flow)...Summer...88-93 , winter: around 70- 80....
Radiators...mmm...I've always found them blocking in the matrices , regardless of flow....and I expect a good flush would cause the crud to collect in any low point on a system.
Flushing a system????...why???...If there's a problem, throw the failed component away and replace...flushing CAUSES problems...On a car where replacement radiators are still made...buy a new one...where no new ones are available, take it to a specialist for a rebuild!...same as every other part
To date I've replaced the following deteriorated components, or by way of maintenance: Rad, water pump, hoses, front heater matrix (rear removed/ awaiting replacement), stat/ rad caps...at no stage was there evidence of more than a little crud, and no blockage...I've owned it nearly 7 years, and it's 16 years old (bar a few months)...
I fear that the above might not be the case if I'd flushed it, and dislodged the slight residue, only to block the system somewhere.
A faulty system with blockages means engine out, strip, and clean in an ultrasonic bath, or with pressure hoses.....and replace duff bits.
Removing old coolant:
Drain/ refill with clean mineral water...run for a while (few days)/ repeat drain fill, drain again/ fill with fresh coolant...repeat in 2 years...bleeding every time, carefully....same with all cars.
Same thing with air-cooled vehicle, excepting that you're looking for air leaks!
Cheers
Helen

[roofraisers]

My quoted temperatures for Japanese areas are extremes & I stand by them.
When designing any product, you have to consider the extremes of the environment in which it is going to operate & then factor in a safety margin.

The Great Pretender wrote:-
Ambient average temperature in Japan (max summer min winter)
Sendia 27.9/-2.0
Tokyo 30.8/2.1
Nagasaki 31.3/3.6
Source Japan meteorological agency.
So 31 to -2, sounds very similar to what we have.

I agree with these temperatures, but you can not compare average values of one climate with the semi-extremes of another climate & then put them forward as a comparison in a discussion.

In the U.K. Braemar has the coldest recorded temperature & Faversham has the hottest.
They are Braemar -27.2*C & Faversham +38.5*C
The ambient average air temperatures are (max summer, min winter)
Braemar +9.8/+2.7
Faversham +14.7/+6.5

Source London meteorological office

From these values we can see that the extreme temperature values are similar (quoted in a previous post), but the overall average ambient air temperatures are a lot milder in the U.K. (cooler in the summer, warmer in the winter)

The Great Pretender wrote:-
Now I know the Bongo is a wonder but what sensor does the coolant system use to monitor air temp and how does it open the thermostat to allow full flow?

The Bongo doesn't have such a sensor & neither does any other vehicle (as far as I know), cooling of an engine & therefore the coolant flow around a system relies on a law of physics called Conduction. I'll try to explain briefly & in simple layman terms, some of which I have talked about before.

A hot liquid (+40*C Japan extreme high ambient air temp)can not absorb as much heat as a cooler one(-30*C Japan cold air temp).
Therefore a greater amount of hot liquid is required, than a cold liquid to acheive the same cooling effect.
In a closed system where the volume of liquid is fixed, this greater requirement of liquid results in a faster flow of coolant to the engine block from the bottom of the radiator. This faster flow from the radiator is equalled by the flow from the engine to the radiator & therefore a faster flow through the radiator itself, as the radiator transfers coolant heat to the high ambient air temp.

The thermostat in the engine maintains an operating temperature.
If the engine temperature is slightly above the operating temp. it opens very slightly & allows coolant to pass.If the coolant temp. (inside the engine block) then falls (due to a low ambient air temp. creating -30*C coolant to re-enter the engine from the radiator) then the thermostat will close again resulting in a low/slow flow of coolant through the radiator.
If on the other hand, the engine temp. rises due to hotter coolant entering the engine block from the radiator due to a high ambient air temp.(+40*C), then the thermostat will open wider/further making a larger orifice thus allowing a high/ faster flow of coolant to pass.This larger coolant flow travels through the radiator tubes & the coolant heat is then tranferred to the higher ambient air temperature(+40*C), before returning into the engine block.

Fitting a smaller radiator to your Bongo would result in a faster/greater coolant flow through it, but it may also result in the Bongo being under cooled on a hot day ( as not enough excess engine coolant heat can be transferred to the atmosphere, before the coolant has to re-enter the engine block to absorb more excess internal engine heat). This is going to ultimately result in the Bongo engine overheating & the coolant being ejected from the system under pressure as the coolant boils around the cylinder head.
This senario can be duplicated by placing a piece of cardboard in front of the radiator, reducing the area of the radiator fins for the air to flow through & therefore having less area to transfer the excess coolant heat to the atmosphere. I suspect the Bongo will overheat given time on a hot day!


Your subject heading is "Design Fault" & started with the question below.
Why does the rad flow top to bottom as most of the time it isn't doing that?

I believe the radiator is the correct design. Coolant flows through it in an effective manner & the large area of tubes/fins allows the coolant heat to be transferred to the ambient air temperature efficiently.
I believe that the speed/ re-direction of coolant flow in a radiator does not/ will not prevent sediment build up. It will merely move the sediment somewhere else & cause other problems to occur.
I believe that the real "Design Fault" was that Mazda & most other vehicle manufacturers do not incorporate coolant filtration on their engines to remove particles that occur during a vehicles lifetime.
I believe the largest cause of coolant particles/sediment is mainly due to poor maintenance/human error & not manufacturer design.

I think I have now tried to explain why Mazda may have designed the radiator that's on the Bongo, (why a larger radiator is required in hotter climates).
What different engine components do & how they work together to achieve engine cooling.
What I feel is the real "Design Fault" and suggested ways how "Joe public" may be able to remedy issues that have developed on older vehicles that they have not necessarily owned from new.

Nigel

_________________

[The Great Pretender]

My quoted temperatures for Japanese areas are extremes & I stand by them.

The Great Pretender wrote:-
Ambient average temperature in Japan (max summer min winter)
Sendia 27.9/-2.0
Tokyo 30.8/2.1
Nagasaki 31.3/3.6
Source Japan meteorological agency.
So 31 to -2, sounds very similar to what we have.

I agree with these temperatures, but you can not compare average values of one climate with the semi-extremes of another climate & then put them forward as a comparison in a discussion.

In the U.K. Braemar has the coldest recorded temperature & Faversham has the hottest.
They are Braemar -27.2*C & Faversham +38.5*C
The ambient average air temperatures are (max summer, min winter)
Braemar +9.8/+2.7
Faversham +14.7/+6.5

Source London meteorological office

From these values we can see that the extreme temperature values are similar (quoted in a previous post), but the overall average ambient air temperatures are a lot milder in the U.K. (cooler in the summer, warmer in the winter)

Nigel

_________________

I would love to sit down over a brew and discuss how thing work with you but in an adult manner not as if you were trying to educate a 14yr old.
Lets just deal with the above first.

You make statements that serve no purpose.

"I agree with these temperatures, but you can not compare average values of one climate with the semi-extremes of another climate & then put them forward as a comparison in a discussion."

I didn't, I used the comparison of averages, even the maximums ain't to far apart but you try to use maximum recorded temperatures to try prove a point.
You also use the maximum and minimum recorded temperatures then try call them semi-extremes to try to prove a point.


"From these values we can see that the extreme temperature values are similar (quoted in a previous post), but the overall average ambient air temperatures are a lot milder in the U.K. (cooler in the summer, warmer in the winter)"

If you think that 14.7 is the average max summer temp in Faversham and the min in Braemar is 2.7 you need to join the real world.
I base my arguments on facts, I may get it wrong sometimes but I don't try to manipulate the goalposts.

[roofraisers]

The Great Pretender wrote:-
Ambient average temperature in Japan (max summer min winter)
Sendia 27.9/-2.0
Tokyo 30.8/2.1
Nagasaki 31.3/3.6
Source Japan meteorological agency.
So 31 to -2, sounds very similar to what we have.

I agree with these temperatures, but you can not compare average values of one climate with the semi-extremes of another climate & then put them forward as a comparison in a discussion.

In the U.K. Braemar has the coldest recorded temperature & Faversham has the hottest.
They are Braemar -27.2*C & Faversham +38.5*C
The ambient average air temperatures are (max summer, min winter)
Braemar +9.8/+2.7
Faversham +14.7/+6.5

Source London meteorological office

From these values we can see that the extreme temperature values are similar (quoted in a previous post), but the overall average ambient air temperatures are a lot milder in the U.K. (cooler in the summer, warmer in the winter)

I do seem to have initially misunderstood your temperature figures & have also badly explained mine which is apparent after re-reading the post after your latest reply.
This is what I meant with my figures:-
The average ambient summer air temp for Braemar is +9.8*C, the average ambient winter air temp is +2.7*C
The average ambient summer air temp for Faversham is +14.7*C, the average ambient winter air temp is +6.5*C

This is how I also understood yours & I apologise for stating you were mixing facts.

+31*C for an average maximum high air temperature in the U.K. does seem a bit hot to me though, but I haven't checked out your source as it's now late & I just wanted to clear up this misunderstanding before going to bed.

Nigel