As we know, the Austin/Rover original coolant tanks are dodgy at best and the replacements can be worse and often require a bank robbery to
afford.
Our Sterling cracked a tank over a year ago. I installed one out of a
Volvo 740 using a Volvo 14psi cap (Same thread as Rover but an awkward shape). Worked great under all Aussie conditions. My son then bought a parts car which had some spare tanks included.So, for originality we swapped back to Rover. Two more split tanks later and we found what we consider a great solution.
Use the VOLVO 1993 -850 Tank with 14psi cap.VOLVO PART NUMBER
7365089-001 (Ask for the one without the sensor hole if you don't have
the LCW light in your 800.Im told you could get the Volvo sensor type
and splice it into the Rover one) They are readily available new and
used and are cheap. The outlets are in good positions, I only had to
re route the bigger hose and put a short extension on the overflow
hose. At most, you need to drill two holes in the inner guard for
bracket. I mounted ours using an adjustable battery hold down (mounted
sideways) but you could also grab the original slide on Volvo bracket.
There is no reason not to use the 16psi Rover Cap, I just figure a bit
less pressure on the system is a good thing and the car doesn't notice
the 2psi difference at all. These Volvo tanks are used in another
model that runs at around 20 psi so there is no issue with over
pressure. Ahh a nice NEW tank- I no longer drive with one eye on the temp gauge! I reckon if it works here, it should work anywhere in the world.
The relevant pics are in :-
http://groups.yahoo.com/group/Rover800/ ... 7/pic/list" target="_blank
A pretty neat solution I think."
Photos reproduced here:

