Leaking Alloy Rads
jeffw - 18/10/11 at 09:01 AM
I bought a (very expensive) radiator off a company at the Autosport Show (I'll leave the company name out for the moment). This was their
'Polo' radiator with a fan and fixings. Once it arrive and was fitted it started leaking from where the core joins the side tanks on both
sides but only under pressure. I contacted the company and they, very quickly, sent out a replacement (the next model up as it happened as they
didn't have the Polo one in stock so I ended up with the 'extreme'
.
This replacement does the same thing as the original and, under pressure, leaks from the side tanks where they join the core.
This is very annoying, as you would imagine, and the company concerned want it back to repair.
So the question is do I give up and go back to the £40 Polo rad which doesn't leak, return both Rads and get them to repair one of them or get
out the epoxy? The company suggested that the reason they leak is how they have been mounted (using the 4 screw holes on the rad bolt direct to the
chassis). Not sure what to do......
quinnj3 - 18/10/11 at 09:09 AM
Is it possible that when you are tightening down the screws, you are pulling the frame enough to allow it to leak? What would happen if you suspended
the rad using rubber bobbins? Might be worth a go.
Bluemoon - 18/10/11 at 09:13 AM
quote:
Originally posted by jeffw
So the question is do I give up and go back to the £40 Polo rad which doesn't leak, return both Rads and get them to repair one of them or get
out the epoxy? The company suggested that the reason they leak is how they have been mounted (using the 4 screw holes on the rad bolt direct to the
chassis). Not sure what to do......
Interesting, I also use these holes and have the bottom sits on a shelf using the "pegs".. I suspect the company is correct in saying you
should mount it in a "stress" free way i.e. so it can expand and contract as it heats/cools the mounting holes you used might stop this.
Might have too look at mine (rubber "grommets" might fix the expansion issue..).
I would get the company to fix the rad, i think although it may be worth posting some rad pics and mounting pictures to see what people think about
the quality/design, and if it's suitably mounted so as to allow thermal expansion..
Cheers
Dan
britishtrident - 18/10/11 at 09:18 AM
A hot aluminium rad core expands a fair bit compared to a steel chassis at ambient temperature as on a tintop the rad should be rubber mounted
to allow for expansion.
jeffw - 18/10/11 at 09:36 AM
Good point, I was thinking about vibration not expansion.
If I mounted it on some sort of exhaust bobbin it should allow side expansion.
Do we think it will stop leaking or will it be damaged now and need repairing ?
tomgregory2000 - 18/10/11 at 09:59 AM
it will need to go back to be fixed but you must mount it on rubbers!!!!
Bluemoon - 18/10/11 at 11:12 AM
quote:
Originally posted by jeffw
Good point, I was thinking about vibration not expansion.
If I mounted it on some sort of exhaust bobbin it should allow side expansion.
Do we think it will stop leaking or will it be damaged now and need repairing ?
Well you could try it "unconstrained" and pressure test it (run engine, up to temperature or leak!...).. On my car I have fitted a tyre
valve to allow me to pressure test the system without running the engine, useful to check for leaks/pressure cap works at stated pressure, also check
water pressure when hot by connecting up a pressure gauge... etc..
But I would guess is once the seal is breached you will need to get it fixed, else it will keep leaking other fixes (rad weld and alike) are not a
good idea you really need to get it fixed by the rad manufacturer..
Dan
adithorp - 18/10/11 at 12:36 PM
I agree that rubber mounting it would be better but my Polo rad has been hard mounted for 3 years and 13000 miles and is still OK. (might upgrade to
bobbins this winter). How are your "expensive" ones different to the standard Polo rad? Could that difference make solid mounting it worse?
I'd get the expensive one replaced and rubber mount it and see how it goes on.
r1_pete - 18/10/11 at 01:30 PM
Don't want to hihjack the thread, but, I thought alloy rads were fully welded, how do they leak like this? are there interference or
'glued' joints?
tomgregory2000 - 18/10/11 at 01:38 PM
quote:
Originally posted by adithorp
I agree that rubber mounting it would be better but my Polo rad has been hard mounted for 3 years and 13000 miles and is still OK. (might upgrade to
bobbins this winter). How are your "expensive" ones different to the standard Polo rad? Could that difference make solid mounting it worse?
I'd get the expensive one replaced and rubber mount it and see how it goes on.
Normal polo 'cheap' rads have the plastic end tanks where as the expensive ones have alloy end tanks and therefore have less give in the
fixing points and expand more than plastic
I had a pace products caterham 4 core racing rad and had to rubber mount it (used exhaust bobbins, 8 of them, but could have got away with 4)
02GF74 - 18/10/11 at 05:37 PM
quote:
Originally posted by r1_pete
Don't want to hihjack the thread, but, I thought alloy rads were fully welded, how do they leak like this? are there interference or
'glued' joints?
the header tanks are tig welded but the core is soldered in. I have big alloy tank and is fitted usiing rubber bobbins top and bottom .... glad I did
.... well it has pegs so can't see how I cold have fitted it any other way.
jeffw - 18/10/11 at 06:19 PM
Yeap, So I've bought a cheap polo one which I will fit and then send both of the damaged ones back. When it comes back I'll mount it using
bobbins.