12 replies to this topic

[coopdog]

blown a head gasket on the weekend,
dad just came in and said its dropped a lot of oil on the road,
went out and it has left a fairly big puddle there, what could this be from :/

[dklawson]

Assuming this leak is 100% new, it could be from an improperly torqued head or any number of other areas disturbed when you fit the new head gasket. Before anything else, check the condition of the coolant and the oil in the sump. If you find oil in the coolant or coolant in the oil, you need to drain and refill both AFTER you have replaced the head gasket again AND checked the head for flatness.

I have posted this suggestion before for situations like this but I cannot advise you where to buy the materials in the U.K. There are UV dyes you can add to engine oil that will make the oil "glow" using a black (UV) light. To use the dye, you completely degrease the engine (wash it down to remove all leaked oil and grease). Add the dye to the oil and at dusk in a dimly lit area you run the engine for a few minutes while watching (in the dark) using a black-light or UV light source. The dye will glow brightly on the engine wherever the leak is.

[coopdog]

Assuming this leak is 100% new, it could be from an improperly torqued head or any number of other areas disturbed when you fit the new head gasket. Before anything else, check the condition of the coolant and the oil in the sump. If you find oil in the coolant or coolant in the oil, you need to drain and refill both AFTER you have replaced the head gasket again AND checked the head for flatness.

I have posted this suggestion before for situations like this but I cannot advise you where to buy the materials in the U.K. There are UV dyes you can add to engine oil that will make the oil "glow" using a black (UV) light. To use the dye, you completely degrease the engine (wash it down to remove all leaked oil and grease). Add the dye to the oil and at dusk in a dimly lit area you run the engine for a few minutes while watching (in the dark) using a black-light or UV light source. The dye will glow brightly on the engine wherever the leak is.

i havent done the head gasket yet and had to move the car sunday so do you think its just from where the gasket has gone?
hope its nothing too serious

[dklawson]

Since this is still the old head gasket don't worry too much about leaking oil until you have replaced the gasket.

Before removing the head, wash the engine as I described above. If the leak continues, it will make the leak easier to find with the engine clean.

While the head is off, be sure to check it for flatness. While Minis can blow head gaskets "just because", you should at least make sure the head's mating surface is flat before putting it back on with a fresh gasket.

A commonly overlooked step is that once you have replaced the head gasket you MUST readjust the valves. Don't forget this important step.

[coopdog]

Since this is still the old head gasket don't worry too much about leaking oil until you have replaced the gasket.

Before removing the head, wash the engine as I described above. If the leak continues, it will make the leak easier to find with the engine clean.

While the head is off, be sure to check it for flatness. While Minis can blow head gaskets "just because", you should at least make sure the head's mating surface is flat before putting it back on with a fresh gasket.

A commonly overlooked step is that once you have replaced the head gasket you MUST readjust the valves. Don't forget this important step.

ok thank you
the head gasket went about 2 years ago and the guy who did it then said thers a mark in one of the bores, and said its going to be weak from that, when i get the head off i will take some pics

[Gulfclubby]

Hoping the headgasket was also replaced two years ago;)

[coopdog]

Hoping the headgasket was also replaced two years ago;)

yeah it was :L

[thebullet]

The oil feed!

[mike.]

Depending on where the gasket goes (you won't know until you take it off really) it can increase the pressure in the crankcase and lead to seals and gaskets going, which may be your problem.

[dklawson]

Depending on where the gasket goes (you won't know until you take it off really) it can increase the pressure in the crankcase and lead to seals and gaskets going, which may be your problem.

No, I'm afraid the lubrication system is not capable of causing seal and gasket leaks (excluding the damaged head gasket being described here leaking to the outside at the top of the block). Blow by from the piston/cylinders is about the only way you will be able to force oil out of the seals and various gaskets on the engine.

Edited by dklawson, 15 February 2012 - 02:50 AM.

[mike.]

Oh, ignore me then

[coopdog]

change the gasket but its leaking between the head and the block :/
torque it down all the way still leaking

[Gulfclubby]

Chances are the head is warped or the block is not flat. Also check for cracks, may need some UV dye to find them.