On all my D2's I've completely bypassed the throttle body heater. I do live in Texas and we don't get cold weather here for very long.

I can see the throttle body heater being important up north during the winter, but down in the south it's just another place to leak, and cause a possible massive loss of coolant possibly killing your engine. The OEM hard lines from the expansion tank to the radiator, and throttle body heater were never great from the start. You could replace the OEM hard line with a thick HD rubber line, and repair the leaking throttle body heater plate (another poor design with 3 screws vs 4).

I honestly think the throttle body heater plate is overkill (especially in TX). I have owned many different 4x4's and my 5.3L V8 Hummer H3 for example doesn't have a single thing coolant wise running to the throttle body to keep it warm or from sticking. Now it doesn't have an actual throttle cable like the LR, but that wouldn't stop it from sticking regardless.

One tip when removing the OEM line from the intake I highly recommend cutting the old hose off vs tugging on it. The nipple on the intake is very delicate!!!!

 

Check out this thread, plus this thread linked from the first one.

In the short term at least you can block off the throttle body heater circuit and keep driving your truck. If you want the throttle body heater connected there are plenty of people using 5/16" fuel line hose instead of the more expensive factory nylon line. And just where is your line broken? There is enough give in the system for you to be able to connect a longer stub line between the tank and the nylon hose.

Data on repairs (e.g. J.B. Weld) to the tank are mixed, but why not try them before buying a new tank? Depends on your risk appetite and time vs. money circumstances I suppose.

If you decide to buy a new tank I can share that I bought one off eBay in July 2014 and I'm completely happy with it. I wasn't able to locate the name of the eBay seller this evening but I think I paid less than $40 for it. I can find the name of the seller if you let me know you'd like to know it. (The eBay seller was carpartswholesale and the part number is PCF101410 - $38.51 as of today, with free shipping. New Coolant Reservoir Land Rover Discovery Range 2001 2000 99 97 1999 PCF101410 | eBay)

If you've just replaced the cap why on earth would you buy another one already?

Good luck.

 

These trucks would be 100% more reliable if LR hadn't used so much cheap plastic, especially in and around the engine. From those hard lines that run across the engine to the expansion tank, the oil separator and any number of other little clips and doodads, it's all garbage.

Anyway, I wouldn't consider RTV as an option for expansion tank repair. Your best bet is probably going to be epoxy or something epoxy-like. There are plastic welding kits, but I don't have any experience with them or know how well they hold up. You're best off replacing the tank, obviously, but you could try to bodge something up.

 

I tried the JB weld on my expansion tank with a crack in it. Lasted about 72 hours.

FWIW, I agree that the plastic used by Landy is by and large, garbage.

There are some great billet aluminum universal replacement tanks that fit in the space of the stock one - just gotta fab up a bracket, which can be done with some steel, a vise, a hammer and a drill.

they are less money than the stock rover part, and won't be leaking again in the lifetime of the truck.

It's been my experience with these beasts that leaks are best dealt with with aggressively, and replacing plastic with metal has not let me down yet.

All that being said - your money, your rover, your call.

 

I tried JB weld and it didn't work at all. So I ended up replacing the tank and the throttle body heater hose.
Hear in San Francisco, it never gets cold enough to freeze a throttle. But I like to keep everything stock and original, no matter how useless it really is (my Toyotas don't have anything like that).

Thanks for all your help.
I will post pictures soon.

 

Yeah replacing the tank is the best bet. However I still think the throttle body heater is overkill. Only my Land Rover's I've owned have had them. Jeep 05 Wrangler nada & 08 H3 Alpha 5.3L V8 nada and you hear no stories of them freezing.

I think worn cables, and a gunked up throttle body would cause it vs having a heater/coolant running to the throttle body.