Could it be this simple? Coolant issues

300tdi disco ..

About two weeks back i noticed i had no warm heater so checked the header tank .. completely empty.
So topped it up to the correct level and it started using around a liter a day.

Figured i might have a headgasket issue or a radiator leak ..
But i changed the header tank cap first just incase it was dodgey ..

First day it dropped abit again .. but about 200 miles of driving after no issues at all .. release of pressure when i take it off whereas there wasnt anything before.

Could that be the reason it was using that much water?

If so, im bloody happy

Had a similar thing going on with our old '97 Tdi, could not figure where the coolant was going, and no traces of leakage in the engine/engine bay.
It turned out that the coolant was leaking from the heater matrix, dripping onto the trans tunnel and sneaking under the carpet finding its way out then through a small hole in the drivers side floor, but the underlay will soak up pints of fluid before leakage starts to show below the vehicle.
If you have not already looked there lift the carpets and insulation in the front footwells and see if that is where your coolant is going, it can be a miniscule leak that will take the coolant level down, with a certain amount of pressure being maintained in the cooling system because of micro boils in the head.
And don't trust the temp gauge once coolant level is down , (head tank empty), no coolant=no contact with the sensor that signals the gauge, temp gauge can be falling and head will be stinking hot.
If coolant is lost from the system it has to go somewhere it's just getting to find it, or else sooner or later goodbye head gasket/head.

It could be.

I had the same on my V8, coolant loss, panic, change cap and all was good.

Tried the old cap again and if you went for a drive and got the car hot when you came back stopped and lifted the bonnet you could hear the cap leaking slightly.

I was also very happy!

I really should clean my engine .. cant really tell which leak is which lol.

Had a quick look in the footwell and all seems dry (at work so i cant have a proper look yet)

I might try the old cap aswell and see if it changes anything.

When i first got it the header tank was full to the top, assuming a garage filled it wrong when they changed something .. pipes are new and so is the alternator.

I suppose that could have messed something up.

Rad looks in really good condition so must have been changed too .. noway it looks like its 17 years old.

Sorry to hi-jack this to a degree, but where is the level indicator ona disco 1 300tdi header tank. I cant find one on my 1995 car. ??? And I'm sure it has dropped a bit since I bought it last September

The half way seam of the header tank is the level and which matches the marker that can be seen through the hole sticking up inside the tank after removing the cap, if you can't see either you don't have a genuine tank.
Info is in the owners handbook.

If its only dropped a bit since september shes a goodun !

discool said:

The half way seam of the header tank is the level and which matches the marker that can be seen through the hole sticking up inside the tank after removing the cap, if you can't see either you don't have a genuine tank.
Info is in the owners handbook.

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cheers, got both of those so tank is genuine.

Why don't you just replace the o-rings on the expansion tank cap? 25mmIDx4mm.

if your checking system is full you need to remove the bung on top of thermostat housing and ensure it over flows, you cant put too much in header tank ,it will allways find the correct level if systems good , its a good idea to check rad core is hot all over when vehicles had a run and up to temp the area behind the alternator is a usual place for a leak staining will indicate or not ,but if rad gets hot system starts off full and you still lose coolant without a sign of a leak head gasket is very common

Seems to be running fine now .. no coolant loss at all since changing it .. only thing is the heaters seem to sometimes blow warm when off (and the dial is set to hot) .. setting them to the cold setting stops them blowing any warm air.

owas said:

Seems to be running fine now .. no coolant loss at all since changing it .. only thing is the heaters seem to sometimes blow warm when off (and the dial is set to hot) .. setting them to the cold setting stops them blowing any warm air.

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There's something wrong there. if the heater controls are turned fully clockwise 'hot' the heater should blow hot when the engine has reached it's running temp, either by ram effect or from the blower being on..

If only warm then was your engine up to normal running temp.?

Yeah only when up to temp and the heaters are set in the hot area then theyll start getting hot whether the heaters are on or off

owas said:

Yeah only when up to temp and the heaters are set in the hot area then theyll start getting hot whether the heaters are on or off

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The heater matrix is always hot because there's no "off" so just adjust the air temperature to the cool.

Yeah i thought it would just be normal for it to do that .. best to make sure though cheers.

Is the radiator hot all over or are there cold spots ?

Ill have a check when i get home,
Did just have a look after driving an hour and half for any leaks anywhere .. no coolant but the fuel injector pump is dripping fuel.

Anddd its overheated on the way back .. crap.

owas said:

Anddd its overheated on the way back .. crap.

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was rad hot all over , its quite likely a head gasket ,its not unusual on and old engine they only last so long whether cooling system is in good order or not ,though not will ensure that it does go ,head gasket if it is is quite a simple job on a tdi

Recoverd back, all the parts i Could feel were warm.

Driver has a disco too, said its running way too good to be a headgasket issue ..
Going to flush the system, properly check everything and bleed it and see what happens.

The fuel pump leak wasnt a leak .. more a bloody waterfall! So going to have to change that pipe too.