V6 plumbing

[Greengti1 0]

Hi all

 

i have a v6 205 project I have taken on and I am struggling with the coolant system.

 

it has the Volvo header tank in the scuttle tray and was using the standard 205 gti radiator.  Due to overheating I have decided to switch to the bigger mk3 golf radiator.

 

the main difference (apart from size) is that the 205 radiator has a pressure release cap and feed back to the header tank and the golf radiator does not.

 

this means the return feed to the header tank has nothing to connect to and the water system can release pressure when it gets to hot.

 

It would be very helpful to know how others have modified the plumbing to get over this? I have been looking using google but there is no clear answer.

 

any help would be very gratefully received.

 

thanks

 

adam

Edited February 5, 2018 by Greengti1
Did not put my name

[Hilgie 16 2 Cars]

There must be more mk3 vr6 radiators then, because mine has the feed back to the header tank.

 

Also my 205 GTi radiator did not have a pressure release cap...I think only the base model rads had that!

[welshpug 1,657]

the "vr6" rad isnt specific to a VR6, they're fitted to loads of things, like a 1.4 ibiza, I'll look up the Nissens catalogue later to see if there's a specific number to use.

 

some early factory gti rads had a cap but its not a pressure release type, as Hilgie said its only certain base models that had that.

 

 

I think Goliath used a 205 rad with a metal pipe and a 180 degree U bend at the bottom on his 205.

[Hilgie 16 2 Cars]

4 minutes ago, welshpug said:

I think Goliath used a 205 rad with a metal pipe and a 180 degree U bend at the bottom on his 205.

Yes he did.

[Goliath 94]

11 hours ago, Hilgie said:

Yes he did.

I did many years ago and it was crap!

I now use a vr6 rad with a take off from the top rad hose back to the top of the header tank.

 

Here's a childs drawing of the layout which I made about 10 years ago! For the VR6 rad the layout will be the same except the brown breather pipe will not go into the top of the rad but instead you'll have to fit it on to a T piece just as the top rad hose enters the rad.

[Anthony 1,003]

6 hours ago, Goliath said:

Here's a childs drawing of the layout which I made about 10 years ago! For the VR6 rad the layout will be the same except the brown breather pipe will not go into the top of the rad but instead you'll have to fit it on to a T piece just as the top rad hose enters the rad.

 

I've never plumbed in a V6 conversion so I'm possibly overlooking something, but I'm pondering whether the pipe in green in your diagram above necessary?

 

As I understand it, the purpose of that pipe on the original 8v engine is to help the system self-bleed and to provide some coolant flow near the thermostat during warm up when the 'stat is closed.  On most GTi-6 conversions that pipe is deleted and blanked off on the expansion tank with no obvious ill-effect, and I can't immediately see what you would lose by also blanking it off on a V6 going from your diagram as it doesn't look to have any function.

[welshpug 1,657]

I've not yet found a "VR6" radiator with a bleed takeoff, only the two 32mm plain top and bottom hose takeoffs from a MK3, mk4 use a bayonet click connection.

[Goliath 94]

On 13/02/2018 at 9:04 AM, Anthony said:

 

I've never plumbed in a V6 conversion so I'm possibly overlooking something, but I'm pondering whether the pipe in green in your diagram above necessary?

 

As I understand it, the purpose of that pipe on the original 8v engine is to help the system self-bleed and to provide some coolant flow near the thermostat during warm up when the 'stat is closed.  On most GTi-6 conversions that pipe is deleted and blanked off on the expansion tank with no obvious ill-effect, and I can't immediately see what you would lose by also blanking it off on a V6 going from your diagram as it doesn't look to have any function.

All I know is that without the green pipe it was near impossible to bleed and always had airlocks and overheated. With the green pipe it still requires a nack to bleed it properly but it no longer overheats or has air locks.

[allanallen 528 2 Cars]

Green pipe looks a good idea to me for its self bleeding effect ‘al a’ 8v. 

I always add these into gti6 thermostat housings for that exact reason, fill up the coolant and off you go, no faffing. 

[Hilgie 16 2 Cars]

I don't have the "green pipe". Bleeding is no prolem as I have a bleednipple in that top hose to gete the air out.

[Greengti1 0]

Hi all,

 

thanks very much much for all your replays and info.  Apologies for the very slow reply my project is working on wife, 2 young children and full time job time so progress is sadly very slow....

 

i have taken your advice and got the parts to T off the vR6 rad top hose, this sounds like the best idea.

 

i have offered up the VR rad to the car and it looks like it will be a squeeze to fit it in and retain the original grill position.  If any one has advice in the firing department it would be helpful.

 

thanks again for your time and knowledge.

 

adam

[Greengti1 0]

Hi again

 

i have spent a few hours in the garage trying to fit the mk3 golf VR6 radiator and I can't see How to make it fit while retaining the original grill.

 

the main issue I think is the alternator and exhaust manifold are so far forward the top of the rad can't get under the grill.   

 

I also think I might be trying to mount it to high as the top is only just under the slam panel.

 

I have not done any cutting yet, have others had to cut much of the front of the car or the bumper / valance?

 

if there is any advice I would be very grateful.  

 

Thanks

 

adam

[Hilgie 16 2 Cars]

You need to do a lot of cutting actually. I have cut out the complete radiator support and welded a new one in at the same height as the underside of the front valance. This allows you to drop the radiator below the head and you need to tilt is forward as well.