d15b7 with 113k miles.

it sounds like a rod knock or piston knock, but only one cyl. it gets louder with more load, it usually goes away after warming up but sometimes it does it for the whole ride to work.

no noticed loss of power... uses a quart of oil every 1k miles... smokes some...

adjusted valves last fall and to my knowledge has never had a new timing belt. its been doing this for bout a year now. any ideas?

-chris

 

Ideas? Nope. You haven't even told us where the knocking is coming from. "Sounds like" doesn't cut it.

 

fair enough grumble man.

I cant really get a clear location (bottom end/top end) on it because it only does it under load (quiet when idle or cruising)... its coming from the engine and sounds like a rod knock.

reason I posed the question is because ive never heard of a rod knock or any other knock that goes away after it warms up (piston slap?). some days it doesn't knock at all... im stumped.

I know im not imagining it, with both windows down the sound is louder on the drivers side. I thought maybe someone else has heard of or experienced this condition...

-chris

 

Stethoscope. You should get one. In a pinch a long screwdriver will do. But if you're burning that much oil and smoking I'd suspect rings, I don't see why you'd get piston slap in a stock engine but a compression/leakdown test might reveal more serious problems.

 

I didn't think so either... yay another excuse to buy more tools!

 

You don't to buy more tools than take your care to a mechanic. Best advice right there.

 

I would think if a rod bearing was getting to the very edge of it's life it would allow some knock when cold and then expand to barely be within bottom end of the spec.

The other thought that comes to mind is tapered cylinders from normal wear and sticky rings causing the piston skirt to slap.

One real cheap thing to try is to get a quart of Marvel Mystery Oil (MMO) and pour about 3 tablespoons into each cylinder and let sit over night, drive the next day and repeat for about 3 nights. That should help with the sticking rings possibility. Or it may do nothing at all, but it won't hurt the motor. You can find a quart of MMO at Walmart for 5 bucks in the states.

 

The knocking is very likely a bearing issue. These cars are getting pretty old.

 

I wasn't being sarcastic... I actually like having a bunch of tools. I used to have a bunch and they got stolen so im building my box back up

 

it has such low miles, but it was an old mans or womans car before... short trips... and my wife's cousin lugged the engine when she owned it cause she sucks at driving a stick. rod bearings ARE probably on their way out.

well as long as it holds out till I get the swap next year..

im still going to investigate

-chris

 

If you are in the states, a treatment that might buy you more time is the Xado engine treatment. It supposedly can revitalize the bearings too but viscous fluid friction I guess takes a lot longer for it to work it's magic.

It'd be interesting to see if after about 3K-5K miles if your knocking is reduced or non existent with it.

I know it has quieted my wifes D15B motor down significantly and I'm less worried about it while I slowly acquire tools and then save up a little coin to rebuild my old B7 motor to swap in it.

I've looked far and wide to find any non subjective negatives about Xado Engine Treatment and all I ever have found is the defensive response of snake oil without ever trying it. And lots of interesting positive testimonials and TUV (Germany) approval and also some manufacturers like Mercedes have approved the Xado oil. What that last bit means is up for interpretation, could be the oil meets their minimum oil spec but doesn't have anything to do with the ceramic additive to the oil.

I've used it quite a few times and have never harmed a motor with it. Does seem to keep my MPG up as long as all the rest of the sensors are working properly.

YMMV

 

Interesting treatment plan....might look into it in the future if I ever come across a problem like this one.