Exhaust Manifold Replacement (Honda Civic 1999 D15B Engine and EK3 Chassis)!




My honda civic 1999 D15B engine has had a long crack in its exhaust manifold. I read this is a common mode of failure for my vehicle model.

Time to replace with a performance manifold!

Please note that in my country there is no emissions testing. This installation is perfectly legal where I am. If You need to pass emissions testing then you should not install one of these manifolds.

The manifold in question I purchased from Amazon for 62us.

Honda Civic Ex Crx Del Sol Sohc Dynamik Header 2 Pc. - http://www.amazon.com/gp/aw/d/B0089UEOKA/ref=mp_s...

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Step 1: Removing the Old Manifold.

Safety first as always. I used ramps on my Front wheels, handbrake up, rear wheels chocked, wear gloves.

The old manifold and heated oxygen sensor were easy enough to remove using the O2, 14mm and 12mm sockets with Rachet.

You will notice the long crack at the oxygen sensor location. Exhaust and steam used to actually geyser out of this. I read that this crack would cause the sensor to fail early but I'm not so sure about that.

Step 2: Comparison of Oem and New.

The oem manifold is significantly heavier than the new even without the catalytic converter material. The new exhaust gasket is shiny and thick. I'm not sure how sturdy it is but I used it since I had no alternative.

Step 3: Installing the New Gasket

New gasket slipped on easy. You can see the oem gasket.

Step 4: Assembling the New Manifold.

I took pics showing the inside of the new manifold. It's not a high quality build but I'm hoping it lasts long enough. For 62us from Amazon it's not bad at all.

The entire manifold needs to be assembled prior to going into the car. The inter gasket and bolts all need to be installed properly. Trying to make this bolted connection after putting the manifold on the car is near impossible.

Step 5: Installing the Manifold.

The assembled manifold is fitted in from below. This is the easiest way. The manifold bolts direct again to the engine block.

Here is the trouble part. The new manifold is 2 inches short to the muffler pipe. I had to use a long enough nut and bolt (actually a spare u clamp) through one hole.

The spring loaded bolt I ran into the other hole and used a g clamp to squeeze the spring to allow me to thread the nut. The other bolt for the first hole was easier.

Step 6: The Completed Job.

Looks great! Ah yea. The car runs the same.. I can't find any difference. Nonetheless I'm happy!

My shiny exhaust manifold shall assure my entrance into Valhalla!

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    9 Discussions


    Reply 4 years ago

    Definitely worth it and easy enough job to do. Just buy a tube of exhaust gasket sealant.


    4 years ago

    Will your car function properly with out the catalytic converter? I've been thinking of doing the same with my ford, but I don't know if I will have to put it back in when it's time to smog...

    1 reply

    Reply 4 years ago

    It works fine. My catalytic converter was past its service life so I took it out before it clogged. The car runs a bit better but nothing to go wild about. My water induction counteracts the NOx emissions and my exhaust is not so dirty without the cat.


    4 years ago

    The crack will cause oxygen to enter the O2 sensor area and fool the computer into thinking the car is running lean, thereby increasing the duty cycle of the injector to richen the A/F ratio and it will also cause undo heat in that area, burning out the sensor. You should see better fuel mileage now too.

    1 reply

    4 years ago

    Good mod, where are you from ?


    Reply 4 years ago

    Maybe a slight power gain at higher rpms but nothing to talk about. I only did this replacement to save some weight plus the stock manifold has that huge crack.