1998 FORD EXPLORER
126,000 MILES • 4 CYL • 4WD
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JOHN HO10
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At COLD start-up, RPM's jump to 2,200. There's engine clacking noise due to lack of lubrication to top end. Is this normal? Oil pressure needle immediately moves to "normal." Clacking noise abates as RPM's decrease as oil makes its way to top end.

At WARM start-up, RPM's appear normal, about 1000 without the clacking noise. Then slows to about 750.

I'm concerned about excess wear and high RPM's @ cold start (and foot NOT on gas pedal).
Is there a way to manually adjust RPM's LOWER at cold start? Is something else happening?
Your thoughts? Thanks!
Mar 29, 2013 at 2:04 PM
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ASEMASTER6371
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sounds like the lifters are the noise.

the high idle may be the idle air control valve not functioning correctly.

Roy
Mar 29, 2013 at 2:07 PM
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JOHN HO10
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I'm certain its lifter noise with no lube for this short time period.
After start up, engine idles fine. No surging, or sputtering.
Its just at initial cold start when RPM's jump to 2200 then diminish. The entire process takes about 3 seconds.
Could EGR valve contribute to this condition? Its never been replaced or cleaned.
Mar 29, 2013 at 3:02 PM
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ASEMASTER6371
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no, has no effect on oil pressure at all

Roy
Mar 29, 2013 at 3:03 PM
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JOHN HO10
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I'm concerned with what seems to be higher-than-normal RPM's at cold start about.
I know EGR has nothing to do with oil pressure. But could EGR affect high RPM's at cold start?
Mar 29, 2013 at 3:08 PM
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MA AV
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your car needs timing guides for the clacking noise---very labor intensive the engine has to be removed to replace all of them

high rpm when cold could be leaking intake manifold gaskets that when vehicle is warm the air gap due to heat closes, if this were the case your check enigne light should have came on if the light is on you will need to read the code(s) and report back
Mar 31, 2013 at 7:48 AM