Water pump replacement

[bigdaddycain]

Haydn, Hi,

I'm a member of IOM3 (Institute of Materials, Minerals and Mining) and would happily have the header tanks examined to determine the failure mode.

As you are probably already aware as an experienced and qualified technical expert, there is forthcoming legislation regarding 'Lightweighting for low emission vehicles' that is driving considerable research into the use of plastics, composites and other materials to not only reduce weight and therefore emissions, but the whole life recycle of materials used in vehicle manufacture.

As you know long term operating experience is beneficial to reinforce theoretical knowledge.

Would you be so kind as to send the header tanks to me. I'll advise the details in due course. Clearly any failures are of interest to us.

Would you be prepared to assist our research, which will involve meticulous record keeping and data validation. We can't have spurious data corrupting our research, you understand.

By the way, are you a member of an Engineering Council accredited Institution? Well worth the annual fee for access to technical reports alone.

KInd regards

CP

PS is there an email address we can communicate via?

Pm sent.

[bigdaddycain]

Anyway, starting with the simple stuff, I think it would be great if someone could get a tired / time expired header tank off to you for analysis, and it would be really interesting to receive the 'coroners report'.

Thanks for posting - and welcome

I've pm'd him/her Mike. I have two tanks with "cracks" (inverted comma's until the nature of the tank marks can be determined) That i'd be happy to send off for analysis.

Awaiting a reply pm.

[bigdaddycain]

C'mon Dave. I've rescheduled my whole weekend so I can see your findings. You bottled out or summat?

Its been a bit of a wasted weekend in one way for me as well, three days off and no bongo to work on , my own fault .but it will be worth it ,honest.
Next weekend is deffo water pump and the rest of the jobs to do, even if it rains.

Excuses excuses excuses. Ya should have been a politician.

OK - so next weekend we'll se WADS of pics then? Don't let Ste get near it. I don't want it all polishing. I want to see RAW data.

[mikeonb4c]

Crikey - teh BF software didn't show this thread as having any new posts on it (why does it do that, or am I just useless at using the forum, after all this time). So I must have looked very unresponsive to BDC et al. Meanwhile, catching up on this thread, it seems that IOM3 may be an imposter? Had me completely fooled if so, I can tell you! And I wasted a lot of words with someone who appeared to be an interesting newcomer. Oh well, words come easy to me anyway - never mind the quality, feel the width

[haydn callow]

Don't worry Mike.......this forum can play tricks

[lpgimports]

There is a club in town call the gas workers club, but they regularly have functions and judging by the attire I think they may have CIU affiliation and the Blast Furnace Girls attend....

I did Metallurgy and Materials Science during my apprenticeship in Metallurgy at GEC and though not something I do these days would cast these observations.

Other Japanese manufacturers have used these plastic tanks for water and for power steering and had problems with them as well. I think its either a age or temperature issue in Japan that makes them brittle over time and then they are more susceptible to shock of fatigue and ultimately crack and split or joins de-laminate they go porous.

Subaru use them on early impreza's for power steering and water tanks and there were loads of leaking ones around and they went to a cast alloy with steel top plate tank.

Toyota used them on the lucidas, and lots of issues of leaking and so they revised the design and made it round so equal pressure on all surfaces and they they just split apart at the joint.

These plastics are also used in radiator header tanks and yup they split open at the lip to the matrix as they get old.

Also used as headers for heater matrixes and again the stubs snap off them as they get brittle.

Paul

[munroman]

If anyone has one of these header tanks handy, I would be interested to see what material code, if any, is on the tank.

This would normally be a triangular symbol with a number and possibly a code like PP underneath.

The symptoms described above sound like embrittlement due to plasticiser migration and ageing.

(A non IOM3 member!)

[haydn callow]

On top of the tank.
>PP-GF5<
SAE PP

On the bottom of the tank....what looks like a date code...looks to read 3/99 but I think it came off a older Bongo than that



http://www.google.co.uk/url?sa=t&source ... HNRHthzEKg

[mikeonb4c]

There is a club in town call the gas workers club, but they regularly have functions and judging by the attire I think they may have CIU affiliation and the Blast Furnace Girls attend....

I did Metallurgy and Materials Science during my apprenticeship in Metallurgy at GEC and though not something I do these days would cast these observations.

Other Japanese manufacturers have used these plastic tanks for water and for power steering and had problems with them as well. I think its either a age or temperature issue in Japan that makes them brittle over time and then they are more susceptible to shock of fatigue and ultimately crack and split or joins de-laminate they go porous.

Subaru use them on early impreza's for power steering and water tanks and there were loads of leaking ones around and they went to a cast alloy with steel top plate tank.

Toyota used them on the lucidas, and lots of issues of leaking and so they revised the design and made it round so equal pressure on all surfaces and they they just split apart at the joint.

These plastics are also used in radiator header tanks and yup they split open at the lip to the matrix as they get old.

Also used as headers for heater matrixes and again the stubs snap off them as they get brittle.

Paul

Really, what we are talking about is the Story of Plastics, from garden hose reels, to deckchairs, the children's toys, DIY tools, even (depressingly) UPVC double glazing. The (plastic) material does not last forever (and too often not for long at all) and degrades under u/v, heat, mechanical action, chemical effects etc. I suppose you could balance the argument my saying that it is only it's equivalent to the rusting that steel succumbs to (esp. steel of uncertain pedigree, and I've observed too that some plastics have much better pedigree and longevity than others), but I still mourn the passing of good quality metal products.

But if a plastic topped radiator lasts 12+ years then I guess that - by modern standards - we have to accept that as being a 'reasonable service life'. It still sticks in my craw though, and I mourn the passing of the age of over-engineered products

[munroman]

Thanks Haydn.

So it looks like Glass filled Polypropylene - the 5 is the recycle code for Polypropylene.
This is a good material for header tanks, with a generally long life than Nylon, and a good tolerance for anti-freeze, so perhaps design is more of an issue.

One mode of failure code be that the short pieces of fibreglass in the plastic will have a certain orientation, based on how the molten plastic is squeezed into the mould.

As the header tank has so many baffles and changes in section, it is likely that some areas will be much weaker than adjacent ones, so will flex differently, possibly leading to fatigue failures as they expand and contract in different ways.

Can you look for the 'gate mark', this is where the plastic is injected and is usually a circular mark, probably most likely in the centre of the tank.
I would be interested to see where this is in relation to where you are finding the cracks.

[haydn callow]

Cannot find any "GATE" marks.....(what I would call "sprue" marks.)

The tanks are made in 2 peices and "welded" together....( the flange round the middle just above the FULL line.)