Laguna Radiator Change

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Mon 10 Jan 2005 15:36
Laguna Radiator Change - Pipkin
I've just managed to change a radiator on a laguna. All connected and at the time no obvious leaks. Refilled system and bled at top of rad at the top bleed point (I assume feeds the heater matrix of something). All seem fine. Put cap back on expansion bottle and ran engine. After warmed up a bit, carefully I might add, took cap off to check level - it gushed out. Topped up again and took top bleed to check no air. However, it appears only 'gunk' had kept this in and it no longer threads back in and hence water spurts out of this point.

So after you've stopped laughing can any kind soul enlighten me to if the water gushing out is normal, or if not what is the cause (I suspect it may be the lack of a vacuum caused by the dodgy bleed screw) - and obviously a DIY soultion. Is best bodge fashion can the bleed screw be held own with a jubilee clip successfully, and maybe some PFTE tape?

?!
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Mon 10 Jan 2005 15:49
Laguna Radiator Change - Aprilia
Can't fully follow your post, but here is my answer...

No, bleed screw must fit properly - you need a new hose (I assume its type that fits in hose?).

You should bleed the system whilst filling it - not fill it, get it hot and then bleed!
Water gushed out because air expands when it gets hot - and you had air in the system. Nothing to do with vacuum.
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Mon 10 Jan 2005 16:29
Laguna Radiator Change - Pipkin
Thanks for the rapid reply.

I did bleed whilst filling. After the elation of fitting the rad, I stopped thinking clearly and leaped to the conclusion it must have air in it (which it seems it did), but then made the mistake of taking the bleed screw out - only to find it didn't go back in!. Thanks for letting me now the vacuum bit was a red herring. I just didn't realise that the water would expand so much more because of the air in the system, your advice is a relief - I had a panic attack that it may be something more sinister (to me at least) like the head gasket, although no other signs to indicate this.

You are of course right, the bleed screw does indeed fit in to the pipe. How easy are these to source? I guess fitting is akward more than technically difficult (I am hoping the answer is yes and it is just a load of clips and refilling the cooling system).
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Mon 10 Jan 2005 18:30
Laguna Radiator Change - Aprilia
I don't tend to touch Renaults on principle, so don't claim to be an expert at all. I imagine the bleed valve is integral with the hose - so buy a new hose. Fitting shouldn't be difficult at all (maybe invest in some new hose clips to make it easier).

Give the system a good flush through with clean water and then fill with 50:50 antifreeze mix.

On most cars, bleed when cold and perhaps as it warms up. When water runs cleanly out of the valve (no more bubbles), close it off. Get engine up to operating temp. (cap on) and then let it go cold. Then top up header tank.

Being a Renault you may have to bleed it with the front jacked up, or via a 3-foot long vertical tube, or something else wierd. Others may be able to advise on that.
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