Nissan Repair: Re: Engine Rattle, nissan pickup, spray paint

Question
Hi Calvin!

My responses to your follow-up questions are pasted in below. My original letter is pasted in on the very bottom.

Thank you again!
Dan

-----------------------------------------------------------------------------------

Hi Dan -

If you can give me more information, that would be great - Obviously engine noises come from many, many sources, and the more info you can give me, the closer we can pin it down -

Calvin:
Does the noise come out -
At a certain speed?
Dan:
The noise is loudest now on start-up. It will usually stop alltogether after a few minutes now, but it sounds somewhat like valves sound when maybe the engine isn't getting enough oil into the topside.

Calvin:
Only at a certain RPM?
Dan:
No. it seems to happen at all RPM's
Calvin:
While you are going up a hill, or coasting, or both?
Dan:
Both.
Calvin:
Going over bumps?
Dan:
No. Bumps don't seem to have any impact.
Calvin:
Does it sound metallic, like when you shake a spray paint can? Or like there is a loose metal piece(s) banging each other?
Dan:
Yes. It sounds like something is starving for oil, UNTIL it warms up, then it rattles very little.Its rattles the worst for sure, just as its started and for the first minute afterward.
Calvin:
Does the rattle frequency (or wave) increase with the speed of the motor, or speed of the vehicle, or neither?
Dan:
No, it doesn't seem to. Seems to be constant and sound the same regardless of RPM's.

Let me know -
aloha
calvin

Hope this helps
Aloha
calvin

Hi Calvin,

You were able to help me back in May with my Nissan pickup and getting it tuned up. I'm having additional trouble with it now that I want to describe to you and see if any of it rings a bell. Its a 1993 Nissan, 2.4, 4 cyl, 4x4. I started noticing a few months ago that it was developing an engine rattle. For the first few months, it was only off and on. It would kind of go in cycles where it would rattle for a few seconds, then stop for a few, then rattle for a bit, etc.

In the last couple of weeks the rattle has gotten louder and now it will rattle almost constantly. I noticed something very different about the way it was acting though over the weekend. I had been just using it for short trips, 5 miles to town and back, but over the weekend, I used it all day for hauling firewood and each trip was 27 miles. By the second trip I noticed that it was much quieter and was only rattling a little, by the 3rd trip, it was almost completely quiet. It almost seemed like it took 50 or 60 miles to begin lubricating something?

I was told that it might be a timing chain that was wearing out. Does that make sense? Would a timing chain take some time to get lubed as you drive?
I'm also suspicious that there may be some type of lubricating device that's failing...

Any thoughts on what it could be?

Thank you very much!

Dan

Answer
Hi Dan -

First of all, pardon the question, but Is the engine oil level OK? I have to ask the obvious . . .

Thanks for the detailed information. It sure sounds like a lifter has collapsed, or not getting lubrication. First of all I would try what I call "mechanic in a can". Simply put, an oil additive. Looks for one that says it frees lifters and conditions engines. Normally you would add it to your crankcase and have to drive the car for a while, especially at higher RPM's.

If you are not using synthetic oil, I would definitely change it. Makes a difference, and also saves on gas.

Thanks
calvin