Engine Rattle on Start up, Misfires, Clean Oil

it certainly sounds like the beginning of an hg leak. try a dealer?

 

Cleaning ONLY the pipe does nothing. The passages in the cooler are alot smaller,
But it does sound like a head gasket failure.
A leak down test would confirm it. Doesn't sound like they did that. Maybe just a compression test.
And possibly removing the spark plugs and using a bore scope to look inside and see cleaner
piston tops on the 1st and 2nd pistons.

 

Dang, two threads going now...

 

Yup. Three indications of the HG failure; knocking, misfires, and white smoke. The only better confirmation might be as @ASRDogman said, to do a leak down test and/or visual with a bore scope.

Also, to confirm, the EGR pipe is only a small part of what gets clogged up. Wait till you get a look inside the EGR heat exchanger itself. I've seen them completely packed with carbon. Cleaning it won't fix your HG leak, but it'll make it so the new gasket lasts more than a week or so.

 

Oops! I didn't see that. That always makes a confusing mess.

 

Maybe four: 220K miles and only a (recent?) cleaning of the tip of the EGR "iceberg".

 

These engines are known to run a little rough on startup... Or maybe your head gasket is such a minor leak it tested out ok? Easiest way to test it yourself is to open the coolant reservoir and if it sucks air in when you open it that means you're likely losing coolant via a bad head gasket. Sometimes these leaks are so minor that people can keep driving around town for years without the engine shacking getting worse, but wouldn't recommend a long road trip with that problem. And you'll want to get this fixed ASAP if it's getting worse at a rapid rate so as not to create issues with Transmission dampener.

 

Did you pressure test a warm engine or cold engine? Head gasket test (leak-down test) again warm engine or cold (below 35 degrees)? Your describing systems only on cold starts. You could have a warp that's separating or seeping from the head gasket when it cools down. Take a bore scope and look at the piston heads; is 1 & 2 a lot cleaner than 3 & 4. Does it looks like someone steam cleaned them? Then you've got your answer
Don't run it too long like this or you may irreparably damage it.

Hope this helps

 

Someone mentioned a bore scope. I gather that cleaner pistons indicate a leak?

 

Yes. So would spotting a drop of pink coolant emerging from the head gasket, which is sometime possible with a borescope, while the cooling system is pressurized.

 

How do you rotate the engine to get bottom position for inspection? I don’t recall seeing any belts or pulleys.
BTW, I’m not losing water.

 

Look again, more carefully. You can use a wrench to rotate the (beltless) pulley on the end of the crankshaft.

 

I was only under the hood once doing a clean out and clean up EGR/Cooler/Manifold/Plugs/& sensors.
I recently had the misfire in 40 degrees or so cold start in my garage. 88k miles.
When I do, I’ll post photos of the plugs and scope.
I want to sell it and not stick someone.

BTW, the rattle is about one or two seconds.

 

Specifically: take off front/right wheel, the readily reachable plastic fasteners on the wheel well liner, flex it out of the way, and you’re looking at a bolt on a beltless pulley, on the end of the crankshaft. IIRC the normal direction of rotation is clockwise?

 

You can do all that, but you can see the pulley and rotate the crankshaft with a wrench without removing anything.
Most engines rotate clockwise, as viewed from the non-drive end, except some Hondas (and probably a few other exceptions I don't know about).

 

Ah, just reaching down from above?

 

A loose timing chain would also exhibit this behavior. It takes the CPU a tick or two to compensate and adjust the variable timing and tensioner to kick in.

I'd mark the coolant tank in the morning, cold, and check it every other morning before starting off the day. this will definitely tell you if you've got seepage or head-gasket issue.

Hope this helps..

 

I’m not losing water. After a dealer fix for the ECM recall I took a picture. It did not go down at all over several months.

I’ve never done a bore scope, but it shouldn’t be too hard, but I’m going to search here for advice.