What is up with this Mazda!?
Discussion
Afternoon chaps,
So I have a Mazda 6 2.0 LF (Ford Duratec) engine, also used in the NC MX5.
It failed its MOT on emissions (they didn't bother testing as the garage was filled with smoke!). It smokes a white/ bluey colour with no detectable change in levels.
I ran a compression test and cylinders showed 125 across all four, no variation in any of them.
I have also run a leakdown test and pressure loss is in the 25% range, again with no variation between cylinders and no air leakage to be heard from intake, exhaust, radiator, expansion tank nor dip stick.
What else could cause such an issue? Recently I changed the PCV valve as it was gummed up with oil and I then gave it an italian tune up for around 40 minutes, power was excellent and levels seemed the same (although trying to get an acurate reading on these engines is a nightmare!)
I'm thinking the only thing to do is tear it down and look at the headgasket and oil control rings.
Would an exhaust leak of catalytic converter failure cause excessive smoke?
Bordering on binning the car but I'm kind of attached to the poor thing..
Many thanks
So I have a Mazda 6 2.0 LF (Ford Duratec) engine, also used in the NC MX5.
It failed its MOT on emissions (they didn't bother testing as the garage was filled with smoke!). It smokes a white/ bluey colour with no detectable change in levels.
I ran a compression test and cylinders showed 125 across all four, no variation in any of them.
I have also run a leakdown test and pressure loss is in the 25% range, again with no variation between cylinders and no air leakage to be heard from intake, exhaust, radiator, expansion tank nor dip stick.
What else could cause such an issue? Recently I changed the PCV valve as it was gummed up with oil and I then gave it an italian tune up for around 40 minutes, power was excellent and levels seemed the same (although trying to get an acurate reading on these engines is a nightmare!)
I'm thinking the only thing to do is tear it down and look at the headgasket and oil control rings.
Would an exhaust leak of catalytic converter failure cause excessive smoke?
Bordering on binning the car but I'm kind of attached to the poor thing..
Many thanks
^ Agreed. It does sound like oil in the cylinders. Could be guides or stem seals. OP what's the mileage? Have you fitted the pcv parts correctly? You don't want the engine intake sucking in unrestricted crankcase fumes/oil. Is the intake filthy? Check the oil level and also see if the plugs are oiled up.
I wouldn't dismantle it yet. I doubt it's the oil rings or head gasket.
I wouldn't dismantle it yet. I doubt it's the oil rings or head gasket.
If it is burning oil (bluish exhaust smoke) all the time it is rings/bores valve guides generally cause this after it has been stood & on the overrun for extended periods.
Your compression readings all seem a touch low which tends to confirm this as you should be getting above 175 for good compression on these engines.
Your compression readings all seem a touch low which tends to confirm this as you should be getting above 175 for good compression on these engines.
Kringle said:
Afternoon chaps,
So I have a Mazda 6 2.0 LF (Ford Duratec) engine, also used in the NC MX5.
It failed its MOT on emissions (they didn't bother testing as the garage was filled with smoke!). It smokes a white/ bluey colour with no detectable change in levels.
I ran a compression test and cylinders showed 125 across all four, no variation in any of them.
I have also run a leakdown test and pressure loss is in the 25% range, again with no variation between cylinders and no air leakage to be heard from intake, exhaust, radiator, expansion tank nor dip stick.
What else could cause such an issue? Recently I changed the PCV valve as it was gummed up with oil and I then gave it an italian tune up for around 40 minutes, power was excellent and levels seemed the same (although trying to get an acurate reading on these engines is a nightmare!)
I'm thinking the only thing to do is tear it down and look at the headgasket and oil control rings.
Would an exhaust leak of catalytic converter failure cause excessive smoke?
Bordering on binning the car but I'm kind of attached to the poor thing..
Many thanks
Either the compression tester is broke...the test was not conducted correctly, or the engine is fSo I have a Mazda 6 2.0 LF (Ford Duratec) engine, also used in the NC MX5.
It failed its MOT on emissions (they didn't bother testing as the garage was filled with smoke!). It smokes a white/ bluey colour with no detectable change in levels.
I ran a compression test and cylinders showed 125 across all four, no variation in any of them.
I have also run a leakdown test and pressure loss is in the 25% range, again with no variation between cylinders and no air leakage to be heard from intake, exhaust, radiator, expansion tank nor dip stick.
What else could cause such an issue? Recently I changed the PCV valve as it was gummed up with oil and I then gave it an italian tune up for around 40 minutes, power was excellent and levels seemed the same (although trying to get an acurate reading on these engines is a nightmare!)
I'm thinking the only thing to do is tear it down and look at the headgasket and oil control rings.
Would an exhaust leak of catalytic converter failure cause excessive smoke?
Bordering on binning the car but I'm kind of attached to the poor thing..
Many thanks
ked. 125....well, is that bananas or oranges ?If it is psi...then it is far far far too low. Something is f
ked.You dont offer any history for the car....is this a new problem, does it drive normally, have power ? Does it smoke all the time ? how many miles, has it ever been serviced ? etc etc
What colour/small is the smoke ? petrol, water, oil ?
Whilst smoke is the problem here...it was silly not to do a test and get some actual readings to get some indication of how things are running
It's possible to get reasonable compression figures from an engine that has gummed up/stuck oil control rings which make an engine smoke badly. I'm in the middle of rebuilding a Smart engine that did exactly this, I had to virtually chisel the oil rings out of the pistons, but compression rings were fine.
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