Identifying a Head Gasket Failure

Chances that you are here readings this means you need to know more about head gasket failures and it is also likely someone told you your car needs a top overhaul or your head gasket has failed. Before going on further the first thing we need to know what is a head gasket and what does it do.

The definition per Wikipedia is as below.
A head gasket is a gasket that sits between the engine block and cylinder head in an internal combustion engine. Its purpose is to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders; as such, it is the most critical sealing application in any engine, and, as part of the combustion chamber, it shares the same strength requirements as other combustion chamber components

To summarize - head gasket ensure separation of engine oil, coolant and combustion chamber. Also you need to note that  the end product of the combustion chamber are exhaust gases.

With this you should rough have an idea by now, what happens when the head gasket fail. Right, the possibilities of coolant, engine oil and gases mixing. We can come to the following scenario when the head gasket fails.

1. Coolant + Engine Oil
2. Coolant + Combustion Gases
3. Engine Oil + Combustion Gases
4. Coolant + Engine Oil + Combustion Gases

Of the 4 scenario only those with combination of 1 or 2 are detectable in the system with visual inspection. Your friendly neighbourhood mechanic will usually suspect a head gasket failure based on the signs provided by these 2 failures.

1. Bubbles in radiator spare tank
2. Engine oil cap has water vapour
3. Engine oil is discoloured (think: black coffee + evaporated milk)
4. Radiator spare tank water level drops regularly and require top up

Air Cond Service

I finally decided to go get the truck's a/c serviced. It has been smelling 'sweet' for months when I start up the a/c in the morning. Come to think of it, the air conditioning system in the car is the least serviced system in the whole car. Can't really blame everyone considering everyone that you know that has serviced the a/c ends up telling you how expensive it is or how they got ripped off.


Banly Auto was the hangout for today's service. They have been in business since 1980. The place is definitely the cleanest and most organized one I have visited so far. It feels like visiting a 3S center. Total damage today was RM887.50. Breakdown is as below.

The 2 items that surprised me was the condition of the thermal expansion valve and the cooling coil (aka evaporator). The thermal expansion valve had yellow mouldy looking stuff and bolts on them are super rusted. 

The other surprise was the cooling coil. They it was filled with black gunk all over the surface. Unfortunately I forgot to take a photo of it. The one below shows a dirty cooling coil also but its filled with dust. To imagine how bad mine was, just add water and oil to it.

For those that don't know the cooling coil (evaporator) is located in the passenger cabin. Usually its in the area right under the dashboard in the area under the main blowers behind the console. To think I was driving around with all that gunk gives me the shivers. I asked the guys working on my X to see if they seen any signs that the a/c system had been serviced before. I got a big NO. Gosh.. 8 years of mouldy gunk. Yuck !


After what I've seen today, I'll obediently send it for service every year or two. Maybe 18 months. 


Oh yea.. the nice guys at Banly also put in a nice mod by glueing the outside air intake vent with a thin piece of superlon. Even more prevention for outside odour coming in. 

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