Hello everyone,

I have a 2008 Mazda 3 1,6L MZ-CD and I have been having problems with the coolant system. The coolant is turning black but it doesn't seem to be oil.
I have drained the coolant and flushed the system and now have been filling with only distilled water to test the system and after a short drive, the water turns a dark color looks like dirty water not oil.
There also seems to be a leak somewhere because the level drops but extremely slow though.
I haven't had any problem with the temperature of the motor, but I am having problems with the hot air through.
It is a bit unstable, as I drive with the hot air at max it fluctuates a bit. Sometimes warm and sometimes colder but not how it used to work. Before with max heat, the air was always very hot.
I haven't noticed any white smoke coming from the exhaust.
I have an OBD reader and the coolant temperature is always around 68°C-72°C with the motor warm and driving.

So my conclusion is that the is a problem in the cylinder head gasket that is letting the coolant come in contact with exhaust gases causing the dark color.
Since this is an expensive bill if I go to a mechanic, I am going to but the gasket on Ebay and try to change it myself. I have most of the tools I need but I am unsure of the cylinder head bolts.
I have the repair manuals for the model I have but it doesn't say what type of bolt is used, and before I start taking thing apart I want to make sure I have all the tools.
Does anyone know what type of bolts is used?

Thanks for the help

 

Where did you get the repair manuals, I only have them in Japanese if you have the English could you send it to me please

 

hello Jessica,




Here is the link for the english workshop manuals




MAZDA3 Service Manuals