740 1988 Water, Rad, Pump Cooling system

I thought I had a problem with the head gasket on my 1988 740.

There was a strong smell in the water header reservoir which I now think may
be from changing the water pump, plenty of sealant was used on the water
pump so its possibly the sealant I can smell in the water.

Have just taken the car for a run of 50 miles and have lost no water from
the radiator, if the head gasket was gone should I not be losing water.

There is at time what appears to be quite a high pressure in the water hoses
but this I assume could be caused by the cap on the water res playing up.

If I leave the car overnight when I take the header cap of the reservoir
when the car is cold there is still pressure in the system so this would
again I hope indicate that the head gasket is not gone or there would be no
pressure.

 

You could have a sticking valve in the radiator cap possibly caused by an
emulsion of sealant and coolant. Clean the cap thoroughly inside or replace
with the correct pressure value cap.

Cheers, Peter.

 

What pressure should the engine be at.