Coolant leak...

Lucky me - I'm off on a long drive (800miles+) in a couple of weeks and now my disco 2's taken the opportunity of developing a coolant leak

I've had a look around, there are no holes in the rad, no obvious leaks around the header tank or the coolant pipes, but after only a couple of hundred miles the header tank can be empty.

After a long run the coolant pipes are squidgy - I assume this means there's a leak?

I've topped up the header again and bled it using the screw on the coolant hose to the right of the engine - so this may cure it but time's running out for me

The plastic sump (?) under the radiator is moist only on the the driver's side (RHS) - seems like dirty water. This same sump has a round hole (6") that looks like it once had some sort of cover - now long gone.

This sump looks like a pain to remove - is this a likely area of the engine to collect the lost water or would I be wastingmy time investigating here?

To muddy the waters, on occasions we hear a trickling sound - is this something to do with the heater matrix? Like I know what I'm talking about

Anyway any guidance would be appreciated - I don't really want to set off on my long journey with a coolant problem.

What year of Discovery? What engine?

Peter

I'm gonna guess that it's TD5 and that the expansion cap is fooked if there's no pressure in the coolant system and no visible signs of a leak.

Doh! Yes, its a 2000 TD5.

I did a 50 mile run this morning, popped the bonnet and the hoses were easily squeezable.

Normally when I undo the pressure cap when its still warm I get a hiss suggesting _some_ pressure.

I'll check out getting a new pressure cap - is this a common problem?

Also what about the damp patch on the plastic 'sump' - is this a likely place for coolant to collect?

Cheers all

yes you will get a build up of fluid on the under tray its got nowhere else to go. Coolant loss, Check the top hose clips sometimes the clips cut in to the hose, just have a general look at all the coolant hoses for any signs of chaffing on one another. Oh and keep an eye on the small hard plastic coolant hoses going to and from the expansion tank, they chaff and crack thats how i lost all my coolant, resulted in a cooked head.

I had a leak in my 2001 Td5 which took a while to track down - was from the top of the engine radiator (nearside ) and was only visible with the cowling (top half ) removed .
I also find that to really do a thorough check you need to have a look up from the underside - a leak clearly visible from below can be invisible from above .
I know it means removing the undertray but worth doing .
I have found the spring clips can lose some of their tension over time - particularly if they have been removed for any reason . I had to change a few of mine due to slight leaks and replace them .

Thanks everyone - a nice list of things to do this weekend.
I found the attached image lying around on the web - seems like a handy pic to use as a 'checklist'.
I'll report back with my findings - but I'm hoping the new expansion cap I'm fitting this weekend'll be enough

Same problem to my Td5, the top hose is "squidgy " even if the engine is at normal temperature, no coolant leak(it was on the cylinder head elbow but now is OK) . No hissing noise when loosing the tank cap... Maybe the cap is to be blamed? Other opinions?

flay said:

Same problem to my Td5, the top hose is "squidgy " even if the engine is at normal temperature, no coolant leak(it was on the cylinder head elbow but now is OK) . No hissing noise when loosing the tank cap... Maybe the cap is to be blamed? Other opinions?

Click to expand...

My first question is - do you know how to top up the coolant properly?
I didn't and I believe this contributed to a lot of my fears. Yes, I have a minor leak - about 100ml over 800 miles but nothing too serious in a car of my car's age.

You need to:
1 Park on a level surface
2 Unclip the rigid thin pipes that lead up to the expansion tank
(but do not disconnect!)
3 Undo the bleed screw on the big rubber pipe about 15cm/6" behind the RHS of the radiator
4 Undo expansion tank cap
5 Unclip the whole expansion tank and raise by around 10cm/4"
6 Check to see if coolant is leaking from bleed screw.
7 If necessary, add coolant (the OAT one mixed with water) to the expansion tank until it runs freely from the bleed screw.
8 Replace bleed screw
9 Replace expansion tank
10 Top up expansion tank until full mark
11 Refit expansion tank cap
12 Clip hoses back into place

I have to say, though, no hissing after a long run will have to be some form of leak somewhere. But youcannot properly gauge this until you have filled it up properly.

Good luck!

Thank you for the advice! A lot of work, but I prefer using a syringe and to fill with water through the bleed screw until filled up.
I did it, changed the cap, bleed when the top hose becomes concrete hard, and in the last 3 days I tested it for 2000 miles and no problems at all.