Coolant expansion tank repair.

[normspanners]

I would plastic weld it if I 'had too' but I think I would make a new ally one or at least look for ready made versions

 

[ajlelectronics]

This is the one fitted to the 2.8 I run. The mounting ears seem to be missing from the ones I have found though.

 

[steveo3002]

those vw ones are cheap new....and the blue cap is a later upgrade

 

[Rig Pig]

I think a long wonder round a scrapyard with a camera and tape measure is going to be the best way.

 

[normspanners]

Personally I dont think the vw looks the part IMO especially with vw all over it. I will have a look and see if I have an old tranny one hanging round as I have several trannies hanging round ( but dont tell the wife )

 

[dazza]

There are a few option with the cap on the VW.

audi r8 or Porsche 911 for around £27

 

[ajlelectronics]

Interesting! I have found an Audi tank that is a possible, just need to find one to offer up...

 

[zx9]

Interesting! I have found an Audi tank that is a possible, just need to find one to offer up...

View attachment 96976

Looks like the one on my A4 (B5) if you need any measurements let me know.

 

[hotrodder]

Fair comment. The reason for that particular tank is that I am trying to keep as close as realistically possible to the Middlebridge design. The GTC was the Middlebridge that just missed being produced before they went out of business. I want this one to be "that" car. However, being sensible, I have to try to use available parts rather than track down a one off that I then need to replace in the future, with the same sourcing problems.

I have been looking for a new replacement that will fit, but drawn a blank so far of something with the ports in the right place and that will fit the space. If I had acces to a dozen possibles, life would be easier, but I am having to go by pictures and descriptions.

A query... I assume that the capacity is important? With a 2.9i engine and big radiator, there will be a fair expansion, maybe I could see what it blows out and use that new level? There is a VW? globe design tank that I could use a bit closer to the front, but it isn't very big.

Recreating a previous special faithfully makes more sense. Like you say taking liberties to avoid painting yourself into a corner is sensible though, especially as they probably only used that header tank 'cause it was cheap and common at the time

W124 header tanks are a fairly similar shape but the 10mmish return bleed/vent, while pointing in a better direction, is at the other end. Outlet is ~ 22mm and they use a conventional rad cap so also have an overflow (puke tank is hidden in the inner wing on them). I think all of them are desgined for use with a coolant level sensor so might not exist without a hole for the sender (round fitting, O-ring seal and secured with a circlip)

Capacity isn't that big of a deal as long as it's large enough to always have coolant in it and enough space for expansion. Obviously mounting height also plays a role with regards to the min level as to function properly it needs to be the highest point in the system
Off the top of my head i reckon a 124 header tank is ~ 2 maybe 2.5 litres (total coolant capacity of my 3.2 is 9.5 litres), i've drawn the cold max fill line and roughly where the level ends up on a hot engine on this nicked pic



although personally i run the cold level about an inch lower than that