1998 Cobra Blowing Blue Smoke

by Keith B
(Wake Forest nc)

Question:

1998 Cobra Blowing Blue Smoke

I have a 98 Cobra with 150 thousand miles. It is starting to blow blue thick smoke.

I can also hear a low tick that seems to be a manifold problem. All the miles are commuting miles I drive about 48 miles way five days a week.
I'm concerned I may have to sell it if its a head basket problem.

Answer

Your 1998 Cobra blowing BLUE smoke means it more likely blowing oil. Typically, when you have a head gasket issue, you are going to see white smoke, which comes from coolant and water leaking across the broken head gasket into one or some of your cylinders.

Blue smoke could be a bad valve, rings or just plain old wear and tear on your motor.

The before you go any further with the 1998 Cobra blowing blue smoke, I'd suggest that you take it to a trusted technician and have them do a diagnosis on it. Specifically, you want to do a compression and leak down test on your cylinders to see what is the cause of the oil burning on your 98 Mustang Cobra. It will also diagnose whether or not you have a head gasket problem.

You can also get a good idea as to the likelihood of a head gasket failure by checking your oil to see if any coolant has got into it.

When coolant is in your oil (from a broken head gasket) your oil will look kind of milky, or murky.

Clear clean or dirty oil, pretty much eliminates the possibility that your pony car has a head gasket problem.

That low tick could be a number of things and could certainly be related to the oil burning problem. Higher pitched ticks tend to be head and valve train issues and low knocking sounds are more likely to be bottom end problems like a connecting rod.

Either way, get the tests done and then decide!




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Comments for 1998 Cobra Blowing Blue Smoke

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blue smoke
by: Happster

It's likely your rings or valve seals, or your cylinders are warped oval.

I agree that a head gasket is unlikely to only breach between an oil journal and the cylinder, which is what would have to be happening if you are only losing oil and not antifreeze and there is no oil in the antifreeze or vice versa.

When a head gasket goes it's generally regional and goes across all ports. A simple compression test will tell you if your rings are bad in one or more cylinders. Should be about 120 lbs in each cylinder and they should not vary greater than 10% between any two cylinders. Look at the plugs when you take them out and compare them to see if one or more is gummed up with oil.

If its a valve seal, they are actually fairly easy to replace with the right tools. You need to rig up a fitting for an air compressor to put air pressure to the cylinder, so when you take the valve spring off it doesn't fall into the cylinder. I used a compression tester ($20) from auto zone, cut the gauge off of it and fit the air hose connector on that end with a hose clamp. Take off the valve cover and screw the tool you've made into the spark plug hole, connect the other end to an air hose and put air pressure to the cylinder. Put that cylinder to top dead center, in case you lose air pressure. Take the valve spring off with a spring compressor (special tool).

Then the seal is right there to pop off. Make sure you don't lose air pressure, or you could be taking your head off.

Great Help Happster !

That's one of the best ways to use air to hold the valve on the seat I've heard.

Cheers!

Bruce

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