Just installed brand new head and head gasket in my 2001 Honda Civic SOHC. The block was machined and new head bolts were used.

I started it up ran for a short couple minutes and shut it off due to massive amount of white smoke coming from exhaust.

Everything is done by the the book and to the specs and torque requirements.

What could be causing this?

Did I just not let it run long enough to burn off or could my rings be bad? I haven't done a compression or leak down test yet but that's my next step.

I am just hoping to get some thoughts on this before hand.

  • Welcome to Motor Vehicle Maintenance & Repair! White smoke is usually a sign of burning antifreeze. Did you use new head bolts? Did you check both the new head and the block mating surfaces for flatness? If so, how did you go about that? How did you clean the block mating surface? Jul 15, 2021 at 23:14
  • Block was machined and new head bolts used Jul 16, 2021 at 1:46
  • So what was the underlying reason why you had the block machined and you replaced the cylinder head? I'm guessing that you had a severe overheating situation that warped the head. If so, there are any number of other issues that may have occurred as a result and you should check for them. I agree, compression and leak-down tests are in order.
    – jwh20
    Jul 16, 2021 at 11:44

2 Answers 2


bad ignition coil? if coil on plug thats what happened to me after rebuilding a 2004 bmw engine. Thought i was going to have to redo everything turned out to just be a bad ignition coil?


I just did a head gasket job and upon startup, there was no smoke; something is definitely out of place in your case.

A leak down test will confirm that the head is still leaking coolant into the combustion chamber. Doesn't need to be anything fancy, just hook some compressed air up to each spark plug hole (while the valves are closed on that cylinder) and watch the air bubbles come out of the radiator or coolant reservoir. Take note of which cylinders produce bubbles, as that will help lead you to the root cause.

Verify that the new head and head gasket match the block in your vehicle. Perhaps you got a slightly different variant with water jackets that don't line up with the block.

Triple check your torque specs, make sure they are correct for the exact year, make and model. Torque specs are known to change even between years of the same generation vehicle.

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