P80 Fuel tank - what type of plastic? [HDPE with Nylon additive] Topic is solved

Post by **BlackBart** » 23 Aug 2019, 14:15

Does anyone know what specific type of plastic the 850 fuel tank is made of? Is it an HDPE? I may be able to find some symbols on the tank if I pull it.

It takes a very specific kind of epoxy to work with plastics. And if you use a plastic welding rod type of system, it needs to be the exact material or it won't bond. I'm going to repair the crack at the heat shield.

Thank you -

Post by **abscate** » 23 Aug 2019, 15:29

ITs going to be one of HDPE, PP, or EVOH

Ill have a peek at mine later today and see if I can smell it.

Post by **scot850** » 23 Aug 2019, 23:19

Which P80 was it that had a recall for fuel tanks issues?

Neil.

Post by **BlackBart** » 23 Aug 2019, 23:37

Mine. I believe it has expired some time ago, and my closest dealer is 3 hours away anyway.

The leak is coming directly from the rear heat shield bolt. Many others have said the same thing....6 gallons is all you get before it leaks there.

Post by **BlackBart** » 24 Aug 2019, 08:34

All I've found so far....

Post by **BlackBart** » 24 Aug 2019, 13:44

This guy says it's polypropylene on a 700/900 series tank -

https://www.volvoclub.org.uk/faq/FuelTankRepair.htm

According to the wiki....

Plastic high-density polyethylene (HDPE) fuel tanks made by blow molding. Blow molded HDPE can take complex shapes, for instance allowing the tank to be mounted directly over the rear axle, saving space and improving crash safety. Initially there were concerns over the low fracture toughness of HDPE, when compared to steel or aluminum.

Post by **abscate** » 24 Aug 2019, 15:42

I think polypropylene will be too brittle at low temp for a tank.

Mine feels like HDPE. If you can wait a few days I can take an IR spectrum on mine and put this to bed.

If you can’t wait, try gluing a piece of hdpe and pp to it, after cleaning. Only one will stick

Post by **BlackBart** » 24 Aug 2019, 17:25

I think you're right - HDPE from most of what I've read. Volvo parts man couldn't help.

No hurry, I'll figure out draining my 5 gallons, and drop it in the next week. There are usually some material marks molded in to most products. Funny that HDPE is #2 milk bottles. But I want to find the correct welding rod.

The left heat shield will stay off, but I've heard of someone having it welded to the exhaust system at the tailpipe, so it doesn't come near the tank.

Post by **abscate** » 25 Aug 2019, 04:36

Float test to separate by density link here, if you can get a small test piece somehow

https://www.4spe.org/files/HandsOnPlastics/day4.pdf

Post by **BlackBart** » 25 Aug 2019, 13:04

This has made my recycle bin so much more interesting!