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Having recently removed the header tank I noticed it was full of broken red plastic bits which presumably used do something useful!

The cooling system certainly got a good flushing in case any bits got caught in there. Now I am curious as to what this used to do and does it matter. It was like playing with a babies rattle toy trying to get all the bits out. Fun though.

Also, can someone tell me what the water level should be in this tank? All the past references to the 'top of the red indicator' have never meant anything on this car. I've always had it about 1" from the top.
Hi Gav,

Within the header tank there is a red/orange plastic baffle. I'm guessing at its purpose but I presume its there to try to prevent air being sucked down to the tank outlet and being dragged into the pump. The presence of the plate will keep the choppy surface of the water away from the outlet to the pump at the bottom. On one of my 2.5's the plate broke up just like you described. God knows where all the its went. I'm pretty sure I didn't get all the bits out of the hole on the top of the tank.

My solution was just to buy another second hand tank with the plastic insert still intact.

Hope that helps.


noz cool.gif
Hi Gav,

Presumably the bits are the remains of the baffle / water level indicator. The header tank should be filled to the top of the indicator which is exactly 2 inches below the top surface of the filler cap flange. (Measurement from a 2.5TD). I hope that helps.

Water level is a interesting issue, in mine I also get it constantly 1cm under the indicator, no matter how much I fill it up, couple of days after. I don't think there is any crack in the block as I have no symptoms to indicate that. Someone on th XM list reported that his own loss of liquid and consequent smell was due to a brass bit missing from the cap of his header tank which seems to provide some tighter fitting to it. He had already gone on to change his heater matrix in search of a cure!

Hi George

The 1cm loss on one of my 2.5TD's eventually turned out to be a pin hole leak from the small rad.


Can I ask how did you find it? Only by looking? Is there any good trick to detect the location of an external leak?
Hi Geogre

When I realised it was losing a small amount of coolant because of the regular need to top up a little I had a good look round underneath but could see nothing.
So I bought and fitted a new rad cap just to make sure it was not pumping it out the overflow. When this made no difference and as I could see no evidence of a leak from the car while parked I took to putting a fairly large piece of white faced hardboard on the ground under the engine area overnight. This showed up the regular little pools of coolant and gave me an idea where it was comming from.
It lasted nearly a year before I got tired of topping up and bought a new pair of rads.


Hi George

Forgot to mention that I gave it a dose of rad weld when I first got the car as it was then loosing quite a lot of coolant. The car then ran for about a year without any coolant loss until the pin hole in the small rad opened up again. Radweld did not work a second time and it seemed to loose about 500ml a week.

Hi All

Anyone worked out why the red/orange header lining breaks up? All mine look to be in a good state. What was the typical coolant running temperature on those cars where the lining broke up?


XM_on_ a_ shoestring
Hi Gav
That happened to me not long after I'd bought my 2.5td estate. I bought a new header tank there's a picture back in December of the contents of my header tank(2.5td estate heater problems). The baffle inside is there to stop the water surging and swashing about, so it does play an important part I presume.
The problem was some of the brocken parts found their way down to the heater matrix. After I'd reverse flushed, forward flushed and any other way, it kept warm for a while. I still believe there are some bits obstructing the heater flow as one minute I get heat coming out then it goes stone cold again. I do intend to disconnect the heater matrix pipes again to see what other muck can be removed.
With the pipes going "downhill" to the heater matrix, they seem to park themselves up on the flow to the matrix. (Check your heater pipes with your hand, if one is considerably warme than the other, then the chances are the heater matrix is or pipes are blocked by some debris.
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