I've got an irritating coolant leak



Judging by the discolouration of the top label it looks as if the cap is leaking



Bearing in mind the nearest dealer is over 100 km away is it worth changing the O ring or are there other internals that might be leaking?

 

Steve,

The cap is listed separately so it must be a fairly regular failure although most of us seem to have cracked tanks before that stage.

Graham

 

Graham,
Do you agree with the diagnosis ?
If the tank cracks where does it usually go?

 

That definitely appears to have been leaking past the cap seal from the way the top of the tank is stained.

Different tank on the SC but the NA usually splits on the bottom, presumably from the heat of the exhaust over time. If this is the cause, the SC tank is likely to fail in a similar location.

Graham

 

I think I've sussed it.
The cap is (as one might imagine) quite ingenious.
The lower O ring in the pic seals to the lower part of the tank neck.
There's a tiny brass poppet valve. When it opens it lets the tank contents communicate with the slot above the O ring.
There's a second O ring up inside the cap so the slot is sealed into the part of the neck where the overflow pipe goes in.
The upper O ring on mine had given up its little rubbery ghost so a small amount of coolant seeps past it when the valve opens.
I've replaced it so - hopefully .....

 

You don't like spending money on the XKR. Not surprised you can afford to own half the Limousin.

Hope it works.

Graham

 

All my wimmin have to learn to live economically !!

 

Steve looking at your picture of the tank it looks as if the hose in the top of the picture maybe leaking around the clap. Looks like a little corrosion wear the hose meets the tank. Try a new hose clamp. .70 us Ha Jim

 

Thanks Jim, I'll have another look.

 

Jim,

Better eyesight than me!




The clamp should be OK as it's a 'Norma' pattern which is either open or closed (no adjustment) but the end of the hose could be shot.

Graham

 

I'll do the old central heating engineers trick + wrap some kitchen towel round it.
Even if the coolant evaporates it will still dye it.
The leak is tiny but I don't like it.
The header tank is always full - presumably coolant gets into the overflow tank when it gets hot and gets drawn back into the header tank as things cool down ?

 

Yes - the overflow is the 'Atmospheric Expansion Tank' in the front wing. If that fills, the excess dumps onto the ground.

Graham

 

I've had a similar experience over the last couple of weeks. I can smell coolant when I'm stopped at a stoplight or after I've stopped the car, however, there are no drips under the car. But, I have been adding about 2 cups of coolant per week or two. From the smell test, the odor is strongest at the front passenger side of the engine bay, maybe some seepage through a loose hose clamp or something. I'm going to pressure test tomorrow and see if we can locate. Smell and the fact that I know there is a small leak drives me nuts.

 

Some great carp fishing in the limousin so i hear, you've got big cats over there too, even bigger than this one.

Sorry you can only see it's gob, but the other pictures were too big to upload.

 

The pic may be taken from an unusual angle but it looks like you need to work on your six pack?

 

Carlsberg or Heineken?

 

Roadhog,
Are you sure that's not a photo I took of the vet putting back a cow's prolapsed uterus?
Yes there is seriously good carp and catfish fishing to be had here.
And.. we've got a gîte.

 

If i'm not mistaken (and as usual i probably am) a gite is a detached guest house.
A couple of years ago i was fantasizing of a house in France with it's own lake and seperate accomodation for visitors, which at the time could be bought for about the same as a 3 bedroom rabbit hutch in England.

Don't tell me you have a lake in the back garden as well?

 

I expect you'll wish you'ld never asked. ;-)

 

That's very kind of you. I'll have a Carlsberg please.

Graham