Former User

I have a 2000 Civic EX (D16Y8) coupe with an automatic transmission. The car and engine have 103K miles, and I have owned the car since 94K miles. The car runs fabulously except that, during only idle, the engine has made a ticking/tapping/knocking sound since it was purchased. I set the valve clearance to spec and flushed the crankcase with no improvement.

After abandoning the ghetto rubber hose method due to difficulties in localizing the sound, I purchased an inexpensive engine stethoscope ($3) from my local Harbor Freight Tool store (I love this store). After spending a couple of days trying to precisely localize this rather subtle noise, I believe that it is coming from cylinder 4. I don't yet know, however, whether the noise is coming from the head (valves?) or upper part of the block of cylinder 4 (piston wrist pin?).

I created this thread to ask what HT members' thoughts are on this noise and how I should proceed in properly diagnosing and fixing this problem.

UndisputedH22a

i dont really know my car is doin the same thing but its a 98 d16y7 ek with about 156000k on it and i know what my prob is its my throw out bearing on my 5spd

DVDr

iTrader: (2)

One of my cars started doing that on cylender 4 also , had higher mileage aprox 180 thousand miles.

Turned out to be rod bearing. After a few months it spun a bearing. d16y8

That being said its not always necesarly that.

I had another car same issue in cold had horrible clanking noise comming from # 4 at aprox 100 k still drove fine till it was sold ( 3 years after and 20 k more ) Buyer was swaping motor out so didnt even bother caring about it. d16y7


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Does it go away after warm up ? or its always there when its idling ?

Former User

Thanks for the questions. The idle noise is never heard on a cold start, but is this because the cold idle is higher than the hot idle? Hard to know.

The idle noise only appears after the engine is hot. Thereafter, the noise usually is heard, though it seems to come and go at times and vary in loudness.

In general, however, the idle noise is only noticeable while sitting in the car with all the windows rolled up. Most road noises will drown the sound out, so it is not extremely loud and instead rather subtle. In addition, if the idle rpms are increased by pushing the throttle pedal, the noise disappears. The engine also sounds perfectly fine and smooth while driving the car in the city and on the highway.

iliv2xlr8

D-series engines are known to be a little noisy. Since you have owned it that long, and it's done this since you owned it, I would say it's normal valve noise.

Former User

I have owned the 2000 EX for only about 10K miles. It had 94K miles when I purchased it, so I really don't know how long the engine has been making the idle noise.

I also should have mentioned that I additionally own a 97 Civic DX (D16Y7) 5-speed with 114K miles. I've owned this Civic since it was new. By contrast, the 97 Civic make no ticking/tapping/knocking whatsoever at idle or while driving.

Hybrid96EK

Y8's are known to spin rod bearings. I would pull the pan and investigate further before you need a new crank.

Former User

The idle sound seems to be coming from the top of block or even possibly the head, so I didn't think the rod bearing was a prime candidate. From my limited reading, a bad piston wrist pin seems to be a better fit. Nonetheless, if I were to pull the oil pan off, how would I easily identify an early-stage bad rod bearing?

Hybrid96EK

Consider this then. When a rod bearing spins, its going to chew up the bearing. The "knocking" noise caused from it is the excessively loose clearance between the journal and the rod itself. The rod is essentially flying around in there. You could very well be hearing the piston itself hitting the head.

I have 3 used Y8's in my garage right now. Every single one of them has a spun bearing in either the #4 or the #3 cylinder. Honda changed the oiling journals in the D cranks when they went to the Y series D's. This is speculated to be the cause of the premature rod bearing failure I am speaking of. For this reason, the Y8 in my car right now uses a Z6 crank instead of the stock unit. I'm just saying its a VERY common problem to find these engines with spun rod bearings. Yours is up there in mileage so its quite a possability.

Remove the pan. If you have a REAL bad spun bearing, the rod will be discolored. Reach up in there and see if you can move the rod up/down. It shouldn't move up/down at all. If in doubt, pull the cap off and inspect the bearings.

Former User

You make very compelling points. I must look into this possibility. Just curious what your thoughts might be on why the sound is exclusively heard during normal idling of a warm engine.

Hybrid96EK

Well, without hearing it myself, its hard to say. Perhaps because with lower rpm you have less "background noise" that makes it easier to pick up? Its hard to say. If the noise is very faint, this would be my guess.

Former User

Yeah, this idea had crossed my mind.

Also, as I understand it, the engine must be pulled in order to fix such a problem. Is this correct?

Finally, you don't seem to think a bad piston wrist pin is involved. Is this because you have never heard of the wrist pin failing in the D16Y8?

Hybrid96EK

I've been a mechanic for years. Played the Honda specific game for the majority of this time. In this time I have built many engines and torn apart even more. To this day I have never seen a stock Honda engine with a wrist pin issue. Doesn't mean it can't happen or it doesn't exist, its just not something I would put my money on if you know what I mean.

You don't need to pull the engine. Just remove the head and drop the oil pan. That is assuming you haven't hosed the crank. If the crank is hosed then yes, pull the engine.

Former User

Thanks much. Your expert opinion is greatly appreciated. I'll definitely take your advice to drop the oil pan and check out the rod bearings, particularly the one for piston #4.

Former User

Thanks again for the advice. After looking at diagrams of the block in the service manual, I could use a few more clarifications if possible.

After just removing the oil pan, can I reach up and check whether the rod moves up or down without removing the main bearing cap? Is there a position for the piston and crankshaft that is best for this test? Can you also give more details about the discoloring of the rod associated with a spun bearing?

And if I do need to remove the main bearing cap to inspect the rod bearings, can this be done with the engine still in the car? Wouldn't the crankshaft be able to fall down after removing the cap? Or is there a safe way to support the crankshaft with a jack? Finally, why must the head also be removed to check the rod bearings?

Hybrid96EK

The head doesn't need to be removed to check rod bearings... not even to replace them. Only if the piston needs to come out of the block would you need to remove the head..

The discoloration will appear in a blueish/purple like color if something has experienced severe overheating. I would reccomend moving the crank to position the cylinder being checked at bottom dead center. Should make it easier to check and no, I don't think you will need to pull the main bearing cap. If you DID need to, the crank won't fall. Remember, its still on the rear main, the flywheel, the clutch, the oil pump, etc.

Former User

Thanks again. You have been soooo helpful.

UndisputedH22a

that is some good advice but i noticed with mine its in the Cylinder 4 area but when the car was warmed up i had my girlfriend push in the clutch which eliminated the noise so therefore i knew it was the throw out bearing

Hybrid96EK

Flawed logic.. Let me explain.

First, the noise was there with the clutch engaged. Therefore the throw out bearing was doing nothing but sitting idle, waiting for you to disengage the clutch. When you push in the clutch and the noise goes away, you are NOW using the throw out bearing. If the noise would come ONLY when you push in the clutch it could be the throw out bearing. With the clutch released, the throw out bearing has nothing to do with it. Now, it could very well be your input shaft bearing. These go out about as frequently as the Y8 kills rod bearings. Seems the D transmissions LOVE to chew up input shaft bearings.

UndisputedH22a

so i would have to replace that how would i go about doin that?

Hybrid96EK

Input shaft bearing? Remove the transmission from the car, split the case, remove the reverse gear, the support bracket for the gear and then the input shaft/countershaft/shift fork assemblies. Then you can get to the input shaft bearing to replace it. Should be about $35 or so from the dealer.

Arthas

Did you find out the problem?

Arthas

I cant PM you soooo..

I was wondering if you could help me out with a problem im having. I have a SOHC ZC with an HF turbo set up. I purchased a chippped P28 and I installed an OBD1 dizzy. All 3 dizzy points do not line up, but I got it to line up with 2. I put on the spark plug wires as I thought they should go but the car does not want to start. It cranks, but it doesnt turn over.

I have a picture and more information in my thread.

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/p28-boosted-sohc-zc-does-not-want-start-2585448/


Thanks for your time. Youve helped me out before with great success!!

Arthas

bump

Former User

I think you need to get a different (correct) dizzy.

Here's the proper firing order:



My engine noise comes and goes and hasn't worsened. I'm still try to precisely pinpoint the source of the noise as it isn't very loud. Wish me luck.