Mazda CX5 2.2 blowing through oil cap
- Thread starter Justyjust
- Start date
You're correct why would someone remove the oil cap when the engines running, I don't know why I did because I normally turn the engine off before checking The oil.
Anyway it does blow a lot I haven't noticed any water loss or oil consumption, could something be causing it or do you think it's normal??
Cheers
Anyway it does blow a lot I haven't noticed any water loss or oil consumption, could something be causing it or do you think it's normal??
Cheers
Last edited:
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- Canada
Assuming you're referring to the exhaust, it could be a number of things, but most of the major problems have clear symptoms. For example, dense, white exhaust smoke that takes a while to clear is evidence of coolant in the engine oil. Exhaust that comes out blue and smells like oil or fuel is evidence of oil/fuel dilution or excessive oil consumption. If the vapours disappear quickly or decrease significantly after startup, it may just be condensation in the exhaust that is evaporating into steam when the hot exhaust gases pass over it.
If ambient temps are starting to drop where you live, this would make the exhaust vapours more visible as well.
If ambient temps are starting to drop where you live, this would make the exhaust vapours more visible as well.
It appears he is talking about "puffing" out of the oil filler cap when the engine is running. That can be caused by crankcase pressurization due to blowby past the piston rings. He did mention PCV valve and in a diesel (which I'm not familiar with) a plugged PCV valve may allow pressure buildup if the system is designed for aggressive crankcase vapor removal. Also remember that combustion chamber pressure increases ring sealing and at idle the CC pressures are low. I remember seeing diesels slobbering oil out of the mufflers at idle but none when under load. Who is the resident Mazda diesel expert on this board. This is out of my realm of experience.
Justyjust, that blowby is normal. If you have variations in antifreeze, *then* you have a problem (with a blown head gasket).
As posted above, combustion forces *some* exhaust past the rings, into the crankcase. At small throttle openings, the rings are not forced against the cylinder walls very tightly (higher combustion pressures actually force the rings harder against the cylinder wall).
As posted above, combustion forces *some* exhaust past the rings, into the crankcase. At small throttle openings, the rings are not forced against the cylinder walls very tightly (higher combustion pressures actually force the rings harder against the cylinder wall).
Jack Rabbit
Banned
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- 18 Mazda CX5 AW
Like skid says, it's normal.
If no oil/air came out while running, that would be bad as the pump was weak/malfunction. If water/antifreeze comes out that's a whole different problem.
I have checked this for every used car I considered buying...pop the cap, place hand over opening and should get drops of oil on hand and feel slight air pressure.
If no oil/air came out while running, that would be bad as the pump was weak/malfunction. If water/antifreeze comes out that's a whole different problem.
I have checked this for every used car I considered buying...pop the cap, place hand over opening and should get drops of oil on hand and feel slight air pressure.
If as you describe you are seeing and feeling , this is normal.
I can post a short video if needed but I can see there is already a few dozen on the www already
.Can you post a video of the cap 'dancing' so I can see what normal looks like please. I am wanting to buy one, but in the pre purchase inspection the mechanic said it was bad. I want to compare it.If as you describe you are seeing and feeling , this is normal.
I can post a short video if needed but I can see there is already a few dozen on the www already
Hi can you tell me if this looks normal please
