Heater exhaust melting undertray - ideas?

[Eclipse Custom Vans]

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Hopefully the pictures show the problem easily enough. A metallic scrape as I was coming off my driveway eventually lead me to look under the van. The diesel heater exhaust has heated up so much that the heat has melted the undertray through which it extends. It's a new undertray after the old one broke going through water in March and it was probably the first prolonged use of the heater about a month ago that's caused this. A garage installed the undertray and I asked them to put the round hole in the tray where the hole in the old one was to accommodate the exhaust. Looks like that wasn't done well enough. You can see that the exhaust is/was touching the plastic and as it's melted the exhaust has continued moving down (or to right in the pictures) and when the exhaust has cooled the melted plastic has set in that corrugated pattern - I had to break the pipe away from the plastic that had melted onto the exhaust, this has at least corrected the angle of the pipe and the driveway scrape.

At the moment the exhaust seems to be sitting as per the pictures above but once the heating goes on again it will probably continue melting it's way to a point where it will naturally stop through lack of force, but how far I don't know - I've no ramps so can't easily take the trays off. I've no idea how or if the exhaust is secured somehow above the tray.
Any thoughts, comments?

Hi, the exhaust gets very hot, as you now know so shouldn’t be near the plastic which melts. It needs to be kept behind this and egress via the dedicated outlet or through the metal heatshield. Not sure what heater you have but the exhaust does not look like a Eberspacher, Webesto etc.

The pipe need to be supported adequately else it can move an touch something creating problems. I would take panel off, reroute pipe and then repair the hole.

You could use a hull egress port like this which may fit in the hole you have to save extending the pipe pipe but I am not sure if yours will fit.

 

[oldiebut goodie]

I wouldn't use a boat exhaust outlet - they are far too heavy an object to be waving up and down with/in the plastic and that Chinese exhaust is too flimsy to take that as well.

 

[Eclipse Custom Vans]

I wouldn't use a boat exhaust outlet - they are far too heavy an object to be waving up and down in the plastic and that Chinese exhaust is too flimsy to take that as well.

I wouldnt either, just an option to overcome his current predicament, just needs re routed and supported properly. Even though OP asked for them to put the exhaust there, why they didnt advise acordingly is beyond me....

 

[Steved55]

I've just in the last hour installed my heater exhaust, and as a previous post, I chose to route mine towards the centre of the van cutting a hole through the side of the undertray where it's aluminium, not plastic to prevent this problem

 

[KR.]

I'm picking up some ramps tonight from a workmate and weather permitting will get that undertray removed and have a look at rerouting and/or securing the exhaust.
This is the second van I've had with the same heater and exhaust down through the undertray, I've never had any problems in those 5 years until the undertray was replaced recently and the pipe was then touching the hole in the undertray. I'll report back when I see what the situation is.

 

[KR.]

Got the ramps last night but in the end they were too steep to drive the van onto so I found out that I could squeeze underneath and work on the tray after all! 4 x 8mm bolts were removed (suspect one of those should have been a star washer) and this allowed me to drop the tray down to see what was going on above. A clamp holding the exhaust had broken so this would have to be replaced, luckily the bracket holding it was in good nick. A quick trip to B&Q produced a metal "Perforated strip" (12 inches, code HEX410) for under a fiver. I cut this and bent it into shape to hold the exhaust and bolted the resulting clamp onto the existing bracket. Tightened the whole thing up - without crushing the corrugated exhaust pipe - replaced the tray, fettled a bit of undertray plastic away from where the exhaust was now protruding. Now the exhaust has at least half an inch clearance all round and is securely held in place.
Sorted.

 

[Dellmassive]

Any pics?

 

[KR.]

I'll tidy up the undertray with some 3mm ABS plastic I've ordered and see if it passes muster for a photo. Hopefully I can solvent weld that one, failing that I'll have a crack with the superglue. Here's the B&Q metal strip bent into a clamp, I managed to round it off a bit better before putting it round the exhaust and bolting onto the bracket.

 

[airhoguk]

I wouldn’t use abs as it’s very flammable around heat and can burst into flames. Your undertray is made from polypropylene so won’t solvent weld to the abs and superglue will breakdown very quickly if exposed to heat, road salt, etc. If your looking at covering the gap I would suggest perhaps riveting in some thin aluminium plate

 

[KR.]

I wouldn’t use abs as it’s very flammable around heat and can burst into flames. Your undertray is made from polypropylene so won’t solvent weld to the abs and superglue will breakdown very quickly if exposed to heat, road salt, etc. If your looking at covering the gap I would suggest perhaps riveting in some thin aluminium plate

Glad I mentioned it then, thanks for that. A bit of further googling does indeed say polypropylene is not suitable for solvent welding. I might just leave it, the hole's untidy but it's no big deal.