VR 6 heater core flush

[Fu Manchu]

I’m aware of cutting the pipes. I think it’s incredibly dangerous. The hoses go onto pipes with no bead and if there ever was some excessive pressure, becomes the weakest point in the cooling system. That’s right where the drivers legs are. It would be a truly horrible pain and easily lead to a major road incident.

 

[losh1971]

I read somewhere on here that a dishwasher tablet is a good chemical flush for cooling systems. Pop one in and drive it for a few hours, presumably over a few days then do a full system flush.

 

[Immortality]

I’m aware of cutting the pipes. I think it’s incredibly dangerous. The hoses go onto pipes with no bead and if there ever was some excessive pressure, becomes the weakest point in the cooling system. That’s right where the drivers legs are. It would be a truly horrible pain and easily lead to a major road incident.

It's certainly a concern however slightly misplaced I think. You cut the heater pipes, put in a new heater with cut pipes that should butt up the original pipes and then slide rubber hose over the joints to connect them. The hose can't really pop off the end of the steel pipe as such, sure it could leak but I don't see a catastrophic failure happening, it wouldn't be a weaker joint than any other in the cooling system where a flexi rubber hose joints to a fixed one, if anything, it would be stronger.

If really concerned, you should be able to flare the pipes with a bead tool.

 

[Dunlop]

Valid point - have never heard of the connection hoses failing though or any warnings about not using that method. I was thinking a lot about it and felt that if two circlips or bolted clips (?) were used on either side of each connection, failure would be very unlikely. As the pipes heat up, they would expand slightly and the rubber connector pipe would become stickier, it would probably help seal even more. Just having four circlips on each rubber hose would probably be enough to ensure a full and safe seal...

 

[Dunlop]

I read somewhere on here that a dishwasher tablet is a good chemical flush for cooling systems. Pop one in and drive it for a few hours, presumably over a few days then do a full system flush.

That's an interesting one - if you put a Finish one in it would probably fix it alright. Can't work out where they get the money for so many ads...

 

[Lacksballs]

You need to make sure the heater tap is OPEN as you try to flush the heater core via the heater hoses under the bonnet… if it remains blocked then the heater core needs to come out. They normally fail well before they block up. Just check someone hasn’t blocked either of the hoses to stop the core from leaking.

 

[Dunlop]

Thanks - easy to forget. I once blew an input hose on a Peugeot when I forgot to open the tap and attached a garden hose to the input hose. My heater is still working - just not super hot and takes some minutes to heat up.

You need to make sure the heater tap is OPEN as you try to flush the heater core via the heater hoses under the bonnet… if it remains blocked then the heater core needs to come out. They normally fail well before they block up. Just check someone hasn’t blocked either of the hoses to stop the core from leaking.