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#1 Corroded water outlet pipe
Posted: Thu Oct 08, 2026 7:51 pm
by Piscator
Dear all,
I have undone the three nuts and spring washers but the water outlet pipe won’t budge. I assume that is because it is corroded to the studs.
I have tried applying penetrating oil (WD40 penetrating oil)to the studs and much gentle persuasion from a rubber mallet to no effect.
What would forum members recommend?
Many thanks
John
#2 Re: Corroded water outlet pipe
Posted: Thu Oct 08, 2026 8:25 pm
by Gfhug
John, which outlet are you referring to? A photo always helps to make sure of an appropriate response. Plusgas and ACF50 are both much better than WD40. Can heat be applied to the location? This does help the penetrating oil to get deeper into threads and gaps. Even between components. And the heat can make one component expand more than another such that it can break the grip. Is there a gasket between the parts? A thin blade might get in there to help break the grip and/or help penetrating fluid get in. Then more heat and gentle persuasion with your rubber mallet. Please try these and any other ideas from our learned friends.
Geoff
#3 Re: Corroded water outlet pipe
Posted: Fri Oct 09, 2026 7:24 am
by mgcjag
Hi John..I assume you talking about the aluminium hose outlet connected to the thermostat houseing and inlet manifold.....held together by nuts/bolts/studs....its not untypical to find these totally seized/corroded....the steel reacts with the aluminium and causes a reaction that forms something like limescale....impervious to penetrating fluids......Iv had a few like this and resorted to cutting through the studs/bolts at the gasket line to remove the houseing.....and then drilling out.the studs...so not a simple job.......look close at the inside of the thermostat houseing it may be corroded...Steve....ps..double nut the studs to try to remove them
#4 Re: Corroded water outlet pipe
Posted: Fri Oct 09, 2026 11:03 am
by Piscator
Hi, Geoff and Steve,
Many thanks for your replies.
I apologise for not making clearer exactly which component I was referring to. As Steve said, it is the casting attached to the inlet manifold/thermostat housing and nearest to the radiator. I will try to attach a photo later.
The WD40 is not the common version and it is all Halford’s had.
The next move would seem to be Plusgas and double nutting, before resorting to anything more drastic.
Ps. The cooling system seems to work fine so I will probably think hard before doing anything.
Thank you, Geoff and Steve, for the benefit of your experience.
John