advice needed


advice needed

went to check oil and water on my sportrak ELX I, oil ok water little low so I check the radiator had noticed that the radiator cap rubber had a slit in it so I got a new one replaced it went out drove about 9 miles stopped for about half an hour went to start the engine had like a mis-start on the second turn of the key it started but had white smoke or steam coming from the rear got home checked oil cap ok no gunge on it let it cool and then checked the radiator had a release of air from when opened it checked water little low in radiator so put some in went out again later drove again 16 miles on return check oil cap chocolate coloured gunge started to appear on oil cap and dip stick all the time the temp was normal water level is still ok but still have steam coming from the rear when driving temp is reached
any advice anybody

Overflow reservoir.

What happens to the coolant reservoir? Take a sniff inside the reservoir, what can you smell?

When the engine is hot remove the reservoir cap. Check for air bubbles rising into the reservoir when you rev the engine.

overfow resvior

Hi mace thanks for the reply, it smells like sweet petrol, and there are small bubbles rising in overflow reservoir tank when is at normal temp, the temp is holding steady and the water is holding steady, and it does not seem to get hot or overheat, but still when the engine is at tick over steam and water drips from the tail pipe which clears at high revs
what do you think mate

Head Gasket.

Head gasket is leaking between a cylinder and a coolant channel. Petrol vapour from a cylinder is being forced on compression stroke into the coolant and then escapes into the overflow reservoir to appear as bubbles. Likewise when the piston sucks in fuel, coolant gets pulled through the broken head gasket and gets into the cylinder. The coolant mixes with the fuel and escapes via the exhaust as white water vapour/drips.
Only a pin sized hole is big enough to cause the problem. However a pin hole is a weakness and no doubt the gasket will dramatically fail when put under strain. If a hot-spot is created the cylinder head could crack or hole.
You probably believe the coolant is not being lost. However the heater matrix is probably filling with 'air' so the loss is unnoticed.
I suspect when starting from cold, there could be a gush/gurgle from the heater matrix from where trapped 'air' being forced into the engine block/radiator/overflow reservoir.

You could ask a garage to do a compression test on each cylinder. The test will show any leakage of pressure.

Head gasket

Hi Mace
thanks for the advice, sounds like you hit the nail on the head
excuse the pun lol
just got to find the cash to fix it now, and that going to harder than finding out what was wrong with it
thanks again