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When I got the paso the coolant bottle was split where the filler neck attached.

I tried various repairs using Superglue, Epoxy Resin and Epoxy based Chemical Metal. After a few weeks the glue came away from the bottle and the leaks came back.

The problem is that the bottles are blow moulded thermoplastic (Polythene / Polyethylene) and the nature of the surface makes repair difficult.

So I tried fusing the surface with a soldering iron but not too succesfully, however with proper plastic welding gear it is possible to effect a repair.

I found an alternative adhesive though which is suited to thermoplastic. Its called Scotchweld DP805, heres the blurb. Its works very well and has repaired not only this bottle but another one where the overflow pipe connection was sheared. So far so good, its doing what the makers claim.


Scotch-Weld DP805 two part, 1:1 mix ratio adhesive offers a three to five minute working life and then builds strength rapidly to give a handling time of only seven minutes.

Suitable for a use on a multitude of substrates, including metals, ceramics, wood and most plastics, DP805 is highly viscous and suitable for application to vertical surfaces without sagging. An oil-tolerant formulation means it adheres well to metal surfaces without the need for specialist preparation.

High temperature resistance, good impact strength and durability in demanding environments make DP805 ideal for external applications such as signage as well as difficult industrial environments.

While its high shear strength means it is suitable for the toughest general purpose bonding challenges.

For more information, visit http://www.3m.com

Gasfireman
I had a similar problem with my 1990 906 after the first few years of ownership from new. I repaired it with fibreglass mat and fibreglass epoxy resin and it has remained solid for a good 15 years.

With that said, it has been off the road for a few years now and I have just inspected the fibreglass repair and it is starting to separate from the polythene bottle at the edges of the repair. Still seems to be keeping the coolant in where the actual leak was, but I might have to do it again with your recommended product.

Dave

If that fiberglass job is done very well and around bottle, its good, but if its done bad way, then it start to leak quite fastly. Have to put many layers mat and all air out from fiberglass and then it function.... Anyway that "polyethene"(Pasos expansiopn tank) is quite "fat" plastic and thats why its quite difficult material to connect with other materials, no matter, what is method.... i have done plenty of fiberglass works with fairings, so i know, how it "behave"...

How much prep work did you do for the DP805, the quikie I tried did not last but one warm up and came off. Did you coat the whole thing or make a hole so it would go into the interior of the bottle? Courious

I roughed it up thoroughly before applying the adhesive with a coarse wet and dry paper then cleaned it using solvent. I found it needed 24 hours to go off but helped its initial cure with a hot air gun.

has anyone tried jb weld? I had a similar problem with my exp. tank and cleaned and scuffed the plastic and cleaned again with xylol and works great so far.

Found JB weld didnt work on mine. Have repaired engine cases with JB weld very successfully though.

I recently repaired mine with a product called Q-bond.

it is a 2 part adhesive, 1 part powder / 1 part low viscosity liquid.
when the parts are combined it sets in seconds

mine had cracked along the bottom seam and up the side to the filler neck
it had been repaired internally and externally previously with:
plastic welding
araldite epoxy
Loctite 571
all at various times by the previous owner and later by me..

the Q-bond has stuck really well
all the others would pick off after a few days - it seems nothing sticks to the plastic and even roughing the joint didn't do much to help.

the Q-bond join is ugly; the seam is like a black bead and a bit rough - just like you had super glued fine granules to plastic - but it has worked so far...

the problem I found with my coolant bottle was the rubber washer that's supposed to be on the cap was in the wrong place - it was sitting in the bottle neck..
when the cap was screwed on the coolant bottle could not relieve pressure out thru the cap pressure valve to the overflow pipe. When the cap was screwed down the valve was closed tight.
I assume the expanded coolant pressure just flexes the coolant bottle under pressure causing any weak joints with poor adhesive properties to fail.

check where your washer is...

Well, I have tried four different things so far, jb weld doesn't work although I swear by the stuff usually, I have tried a product called waterweld, which was similar to jb weld but is specific to coolant related leaks. Then I tried one of those plastic epoxys which are in a two part syringe, it peeled after a week during a long ride. Then I tried a product made by permatex, it is a small kit made specifically for plastic overflow tanks. It was $9.99 and came with a small piece of sand paper, a permatex two part epoxy pouch, a small piece of fiberglass cloth and a little brush. I have only been driving around on it for about a week, but it seems to be a good product. I got it a kragen.

is it the same as on the 907ie ? If so here is one:

http://cgi.ebay.com/ebaymotors/907-ie-R ... dZViewItem

G.