I need some ideas on what this problem could be. I've had this 92 Ranger 3.0 for about 6-7 years and this noise is driving me insane and I can't figure out what it is. When the engine is cold and started, there is a LOUD clacking type sound (like a lifter). After the engine warms up, the noise usually fades away, or gets quieter in the winter. In the winter, this clacking gets louder and is loud enough to hear in the house. It gets faster as the engine is revved up, and really loud when the engine is under load and cold.

When I say loud, I mean kids waiting at the bus stop, turn around to look. It sounds like someone smacking a manhole cover with a hammer.

Now here are the things I tested or tried or points that confuse me:
It gets a little worse each year,
Oil pressure is normal - I put a gauge on at the sender,
An oil change seems to make the noise a little quieter for a while,
Compression tests come out good,
The lifters are new,
Pushrods looked normal,
When I run the computer codes, #6 cylinder is weak or non-contributing,
The #6 spark plug looks similiar to the rest of them,
Engine burns some oil, worse in the winter (1 qt/1000 mi),
I still get about 19-20 MPG with 135,000 miles on it, but it sounds like it will blow apart any day.

The only other thing I have heard of, is getting a hotter ignition coil. So far I've found a 48,000 volt Accel, but haven't tried it yet. Should I try the coil, or do any of you folks have any better ideas? Thanks!!!

 

Have you checked the pulley's? They're have ball bearings inside and tend to go bad. I had the same problem in my other car and it was the adjuatable A/C pulley, after I replaced it, the noise went away. Just a thought of what you should check first, specially for a 135K miles truck.

 

When you stick your head under the hood and listen real good, does it sound like the noise is coming from the #6 cylinder area?

 

No AC and noise not from the pulleys. It definitely sounds like it is from the area of the #6, much louder on that side of the engine. Also, I forgot to mention when I pulled that plug wire off while engine running, the noise was much quieter.

 

hms365:
Sounds like a rod knock to me.
My 81 F150 with a 4.9 has 211,000 miles and cylinder #2 knocks. Your symptoms are almost exactly as mine.

I use 20W50 oil and a bottle of motor honey to help keep her from really banging. It's not a cure, but it does help quiet down the knocking. Good luck!

-hooD

 

Thanks for the info. What sort of failure can I expect when it finally lets loose? Is it worth it to open it up and try to fix it?

Is there any other possibilities or is this pretty much the only problem that fits the symptoms?

 

hms365:

If, and i mean IF, this is actually a rod knock the only cure is to rebuild the engine. Will she eventually fail? YES. But who knows when that moment will come.

Just from my experience i can tell you that if i stay under 50 MPH i can keep the knocking to a minimum. When you throw a rod it can go either up or down. Down through your oil pan or UP through your hood. It's anybody's call.

Again, without me hearing your noise, i can't say 100% that you have a rod knock, but it sure fits the symptoms of one. Any local mechanic in your area should be able to tell you by listening to it if this is your problem. Good luck and let us know what you find out.

By the way, when i pulled #2 spark plug wire off my 4.9L my noise went away also. This verified that clylinder #2 was the problem. Thicker oil will help bridge the sloppyness that is causing the noise but it's not a fix just a band-aid. I have driven over 15,000 miles with a noisey rod.

-hooD