ondfarm

I just bought a 97 hard body with the KA24E. It has the timing chain noise at first start up(sounds like a chain dragging over a piece of metal).Only lasts for a second. Wondering if I should slip the valve cover off and take a peek.
Does that year have metal or plastic tensioners. Also when I crank it cold in the morning it idles at about 1500 rpm. I let it sit about a minute then drive down the road taching it up to about 2000 rpms before shifting and the idle increases to 2000 rpm. About 3 mile down the road the idle will back down to 1000 rpm. Is that normal. I have no check engine lights on. It has 87k miles.
Thanks for any help.

Grug

Welcome to the forum.

Your truck has the new guide types. The older plastic ones were discontinued in '93 or '94 I think.

If your rattle is timing chain related, removing the valve cover won't serve you any real purpose. Have a look at the timing chain fix posted at the top of this section of the forum.

I don't think I'm totally following your idle question...sorry.

SPEEDO

there is a "thermo element" (wax kit)(mounted on the tb) that raises the idle when cold... yours might be going out... once it does, your idle will constantly be high..

lowheels

I also have a 1997 Hardbody, how do you replace the thermo element on the throttle body?

smj999smj

Refer to part code "16391U" on the diagram at the bottom of the page. This is best done when the engine is cold and remove then reinstall the cap to relieve any pressure in the system. The thermo-element sits in a bore in the throttle body as you can see in the diagram. "16394U" holds the element into the throttle body and there should be a lever that engages the plunger of the thermo-element. Remove those two parts an you should be able to R&R the element.

http://www.nissanpartszone.com/Page_...mponentsNo=163

lowheels

Thanks smj999smj! have you ever heard of neoprene and steel timing guides?

smj999smj

The older KA24E and GA16i engines used a plastic, fixed timing guide. Later, these fixed guides and their mounting bolts were upgraded to a countermeasure metal guide with a plastic liner. I suppose the liner could be neoprene, but I can't say for sure. Nissan started using the upgraded guide on the 1995 Hardbody, so later years would have them, as well. The problem wasn't really a bad guide design, but an issue of debris clogging the oil port to the oil-fed chain tensioner, which caused the chain to slack on startup and beat up on the top of the fixed guide, causing it to break apart. The updated fixed guide corrected the issue of the guide breaking, but not the issue of the debris in the oil channel. So, even though one may have a KA24E engine with the countermeasure parts, they still may develope the chain "rattle" concern, especially at start up. Sometimes an oil flushing machine cab remedy this, but in most cases, the timing chain tensioner and oil filter have to be removed (meaning front cover removal) and the oil channel cleared out with brake cleaner sprayed through it, followed by (if available) compressed air.