Header Tank

Improve your cooling system with a header tank!

The Stag Cooling System.

Modern cars, and even many classic cars have a header tank which stores a good reserve of coolant which tops up using gravity. Unfortunately, when it comes to the Stag, Triumph in their wisdom chose to fit a small expansion bottle instead, and this cannot provide the benefits of a proper header tank.  If there is any loss of coolant, this can go unnoticed, and when the coolant drops below the high mounted Stag water pump, overheating will occur followed inevitably by engine damage.  

With a proper header tank installed, there will be a good reserve of gravity fed coolant, and with a low level detector an early warning is issued well in advance of the coolant becoming dangerously low. This prevents engine failure by enabling the driver to stop and investigate the problem before the damage is done.

Stag Header Tank; The Cooling System Upgrade.

The header tank pictured here is a custom designed, lightweight aluminium alloy tank, and being a horizontal cube fits neatly into the spare space on the front left side of the Stag engine bay. The tank supplies coolant to the engine via a large diameter hose plumbed into the intake of the water pump. Coolant circulates through the tank, so any air in the system is returned to the tank via a restricted small bore hose from the top of the radiator.  Note: the tank has been redesigned and improved to make it also possible to fit with a relocated alternator.  To achieve this the lower tank hose position is moved to the end of the tank and is now an AN10 type screw fitting for much more flexibility of installation. A 90 deg hose fitting is included in the fitting kit.

Fitting Kit :

The optional fitting kit includes a float switch and buzzer to warn the driver of ‘low coolant’. The fitting kit also contains hoses, clips, hose adapters, and all other parts necessary to fit the header tank system to any standard Triumph Stag.  Also included are clear, illustrated instructions which should enable most DIY mechanics to fit the kit in 1 hour.  To view the feedback on this product, please click the 'Testimonials' tab at the top.

Which do I order, Mark1 or Mark 2? 

a) Mk2: If your radiator has pressure cap on the expansion bottle not the radiator it is probably the usual Mk2 type and the standard Mk2 kit should be suitable. However, if you have a non-standard radiator where  the filler boss of your Mk2 radiator is too high then add the Mk1 option.

b) Mk1: Alternatively if you have the very early system, with the (13lb) pressure cap on the radiator, you will need the Mk1 option and also to order the 20lb pressure cap to effectively "blank off" the radiator.

c) If you are still not sure, order the Mk1 option as this will fit any standard system.

Pressure cap: To ensure a gas tight seal, we recommend you purchase the optional pressure cap with your tank.

Other information: non standard water pump: If you have fitted a non standard external water pump it is advisable to seek advice from your supplier about installation of a header tank. 

Summary of Features

Here is a header tank kit designed especially for the stag. This can be easily fitted, and will provide crucial cooling system protection for your stag engine. The main design requirements were as follows:

  • To provide a safe additional reserve of gravity fed coolant

  • Incorporate a "Low-Coolant" early warning system

  • Prevent unnecessary engine failure due to coolant loss

  • Circulate coolant to purge it of trapped air

  • Tank has an attractive alloy finish; paint or polish yourself

  • Fits any standard UK Stag (may also fit others)

  • Retains good access to spark plugs and other components

  • No modifications necessary to radiator

  • Complete with all parts and instructions  

Gravity is King!

      Made in England using local engineering resources.

Price: £99.50
For your convenience
You may be able to use your old cap
Mk2 has no pressure cap on the radiator