Loosing coolant from header CDTi

[Busboy]

I am once again loosing coolant from my header, I had this issue earlier in in the year and firstly fitted new O rings to the cap and it didn't cure the issue, I then fitted a new Genuine X part cap and this seemed to solve the issue but now the problem has once again reared its ugly head.

I was told that the tiny return pipe could be blocked so I did clear a small blockage in the elbow where it returns into the neck of the filler, but even though I have done all I think it could be I am now thinking I should change the header as It may even have a small microscopic split somewhere.

Any thoughts?

[Heddy]

Be sure it isn't the elbow on top of the rad, or more likely, the plastic 'branch water outlet' beneath the top cover. The branch leaks and water evaporates very quickly.

[Busboy]

Yes I think there must be a hairline split somewhere as the coolant leaks into the rim around the header.

[T-Cut]

The coolant level should always be well below the tank seam, so if it's leaking onto the 'channel' around the top, it must be escaping at that level or higher up. The seam itself has been known to leak, after dropping the tank onto a concrete floor for example. Has the problem just started or have you always had it?

Another factor is that the typical diesel rarely gets hot enough to cause much thermal activity in the header tank, over-pressurisation for example. This would seem to put the pressure cap and its seals out of the equation. I think one possibility is a leak from the bleed connector tube that enters the side of the filler neck. If that, or the hose joint is dodgy, coolant will get into the channel. Another facet of the bleed connection is that the small hole within the neck isn't that important (more especially for the diesel). Any flow of hot coolant from the head that goes through the bleed hose will drain freely into the header. There's a large drain hole on the inside. This isn't visible unless you use a boroscope or you break the tank in two.

Do you know the usual running temperture of the engine as displayed in diagnostic mode? I think we can elimnate pressure cap related leaks if the engine always runs below say 90C.
Do you think it's ever overheated?


TC

[Arctic]

Hi Keith.
At what level do you have your coolant in the tank please, could you take a photo of it with the cap off, also are you fully tightening down the coolant cap.
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[T-Cut]

This problem also happened in January: https://the75andztclub.co.uk/forum/s...d.php?t=291729
But never between then and now??

TC

[Busboy]

Originally Posted by Arctic

Hi Keith.
At what level do you have your coolant in the tank please, could you take a photo of it with the cap off, also are you fully tightening down the coolant cap.
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2

HI Artic.

I have checked all the connections and also had the h/tank to rad overflow pipe off and checked it's clear and the connections are good, also I keep the level as per the handbook i.e at the upper max mark, But after I have recently screwed the cap on really tight (which I was told not to do)! My header tank leak has ceased!

BUT I now have an un-related minor leak from the Radiator core at the engine side and steam wafts up when I switch off but on checking the header level it's still on Max

The underside of the header is all dry and the connections are leak free. - I am going to fit a new Rad and while I am in there AC Condenser and fan.

[Busboy]

Originally Posted by T-Cut

This problem also happened in January: https://the75andztclub.co.uk/forum/s...d.php?t=291729
But never between then and now??

TC

Correct Artic me thinks it's weather related but I really don't know,

[bl52krz]

Originally Posted by Busboy

Correct Artic me thinks it's weather related but I really don't know,

Hi Keith. If the problem has come about again with the steam from the radiator? I am bringing my project car up to scratch. Last week when we had freezing temperatures, I started the car up and let it run for about 20 minutes, revving it now and again to a steady 3000 revs. While I was round the front with the bonnet open the fan started up on low speed, and a lot of steam came away from the radiator area inside the engine bay. I thought there may be a leak. When the fan came on again there was no steam. The reason being, I think, because when the fan came on the first time it was because the engine had got to the trigger temperature for it to activate, and not being started for a couple of weeks, the damp foggy conditions we had, the water had condensed on the radiator, and when the fan activated, it blew the water through the radiator, which was now very hot, and evaporated back into steam. I have started it up since, and no steam has appeared. I think this is probably your problem hopefully cleared. Also you should tighten the radiator cap down until you can not turn it anymore, using reasonable pressure with one hand .