Head gasket or not?

[mdw]

I've just got a e30 BMW with a suspected head gasket problem. However I'm not sure it has gone?

There's mayo under the cap that didn't clear after a 70mile drive
It never got hot, the temp sat at about a third all the way home.
A friend has done a test on the coolant but it showed no sign of combustion gases

What's people's thoughts has the head gasket gone or not?

[skylinedave]

Do a compression test .

[cobblers]

If it drives fine for 70 miles I wouldn't suspect the headgasket, more like a slightly stuck open thermostat not allowing the engine to warm enough to boil the combustion condensation out of the oil

Don't worry about the HG until you see mayo on the dipstick IMO.

[86corolla]

Mayo under the cap doesn't mean anything..
moister will gather in the cap if it been driven slowly or short distances alot..
If you have done a sniff test and that was ok then you fine

[mdw]

I would have thought the mayo would go after a long run.
What cobblers said makes sense though so I've order a new thermostat and see what happens!

[bortaf]

IME the mayo wont go, you need to wipe it off and then see if it comes back is the water level dropping? if not i'd say it's just condensation and not coolant ?

[colnerov]

HI, as Bortaf says you need to physically remove it, take the cover off as well if necessary. There is water in there and it will just keep on evaporating and condensing.

Colin

[steveo3002]

if the sniffer says okay and no water loss or overheating then it sounds okay

whip the rocker cover off and clean it up along with any breather hoses etc , then a fresh oil change and keep an eye on things every trip until you can trust it

[taurus]

Check oil and coolant levels, check the water dripping from the exhaust - if it's clear fine, if it's coolant coloured then coolant is getting into the combustion chambers.

By the sounds of it there isn't a problem.