Firstly, coolant leaks from the thermostat housing cap of my 2001 Vanden Plas. Car does not overheat - temp always normal, but have to refill coolant after every few days. Is this a leaking seal or some bigger problem?


Second, the electrical fuse controlling the fuel filler cover for same car always blows. It blows at the very first operation after each replacement.


Grateful for any advise on these issues.

 

Even if the pressure cap had released under pressure, the coolant should then go into the atmospheric catch tank. So I think you have a leak, yes.

If the system is not holding pressure, you could potentially damage the engine. The cooling system is designed to be pressurised.

The temp gauge is kind of useless as it is programmed to read N over quite a range of temperatures, and will hide chronic overheating to an extent.

 

+1 on the temp problem.

Check the fuel cap release mechanism, unplug it and then see if the fuse blows. I suspect you have a short at that end.

 

The thermostat housing cap has a large o-ring that seals it. If it is leaking you can remove the cap (use a large hex wrench) and replace the o-ring.
If it is still the plastic thermostat housing then I recommend replacing the whole unit with and aluminum thermostat housing.
There are many threads on the forum to guide you thru but if you need PM me as i have changed the housing on both my V-8's
If the cap will unscrew and the housing is not severely corroded away you can cut a small circle of flat rubber and use it to replace the o-ring. I had to do that on the first aluminum one I installed.

+1 on the fuel cap connector

 

Ooops, I first thought this was a leak from the header tank cap.

Cracks in the thermostat housing and cap are common issues, which is why you can get aluminum replacement parts.

 

It is probably time to change the thermostat housing to the newer aluminum one; also renew the thermostat and the crossover pipe at the same time. On my 01, these had pretty much rotted out two years ago. Lots of threads on replacing the housing: it is not simple to do and your mechanic will probably opt to take the intake manifold off. If so, replace the coolant pipes that run under the manifold, as well.

Getting parts in Africa: probably order from the states -- I used Welsh, but Barrett and others all have parts.

 

Thanks all for your very useful responses. Will order the required parts and replace.