not another sporty on its way out


to cut a long story short this is my second sporty in 14 mts my new ones only done 59000 but seems to be suffering the same has my old one im getting bubbles in the header tank when driven even though its not really over heating could it be a split in the cylinder head or head gasket failure any way ive done a compression test on the 4 cylinders and they all came back at 13.8 bar to 14.6 across all 4 that was the diffrence so it cant be the head the only thing i can think of doing is a pressure test on the cylinders and take the truck to the carage to have the collant checked for exhaust gases that should show it up but to be honest i havent really got the truck that hot could it be a thermostat sticking closed i do like my diahatsus but im getting a bit pissed off with them any other opinion would be gratefully accepted i hope its not the head after just spending 350 on new leafs shocks for the back just put a years mot on and finally got the winch bumper and winch on to

Head gasket

The only way bubbles get into the header tank is via the coolant. Coolant is presurised so anything getting into the coolant must be under greater pressure. Thermostat sticking will only overheat the coolant and the radiator cap would blow. If a hose is holed then coolant would leak.

IMHO the head gasket is blown between a cylinder and a coolant channel - gas escaping at the header tank. The engine might only be showing the problem when fully heated. Cylinder head at maximum expansion - head gasket's split opens sufficiently for gas to escape.

Sniff the bubbles - do the bubbles smell of exhaust or petrol?

head gasket

im sure its the head gasket the hose that goes into the header tank from the radiator is blowing out steam when i pull it out the bottle ive been looking on net and there is this supposed wonder cure its called steal seal but its different than any other supposed cures that it dosent use particles and only takes a hour to work 32 quid a bottle it says its guarenteed to give a permenant fix to 90% heads its worth a try before i go into the time consuming job of taking the head off plus i need to get a workshop cd which isnt has good has a haynes manual for quick reference



In addition to mace's reply, has the engine got an air lock in the cooling system, this would explain the symptoms and why the gauge does not read high. If the temperature sender is in air it reads the air temperatere and not the coolant temperature.

Not a common problem, but one i have seen several times.