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2003 4.0 SOHC Timing Chain Engine Noise

1996ex

Member
Joined
August 9, 2010
Messages
19
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5
City, State
Minneapolis, Minnesota
Year, Model & Trim Level
1996 XLT V8 Control Trac
I have a 2004 Explorer with the 4.0 and about 165k miles and at high RPMs above 4-5k I'm hearing what I think is the timing chain noise from the rear of the engine.

It's sounded like this for a while, maybe even a few years. But it runs OK otherwise.

Should I look into repairing the rear timing chain or tensioners or whatever is wrong preventatively?

I just don't know if I should address it now or later. It's not really a problem because I don't drive it in those RPMs ever.

Thanks for your help!
 




1996ex

Member
Joined
August 9, 2010
Messages
19
Reaction score
5
City, State
Minneapolis, Minnesota
Year, Model & Trim Level
1996 XLT V8 Control Trac
Thank you! You clearly earned a Ph. D in Ford 4.0 Timing Chain issues! I'll drop the lower oil pan and have a look, although I think my oil was recently changed.


What I would do:
1) Drain the oil, remove the lower oil pan & oil pump screen; looking for broken pieces of plastic TimingGuides.
~ If you find plastic pieces you've definitely got broken Timing Guides.
~ If you dont find plastic pieces, you might be lucky: clean & replace the oil screen, put the pan back on with a new gasket.
2) Remove the right passenger side valve cover & directly inspect the right\rear TimingGuide\Cassette.
~ If you find it's broken, you've got some hard choices; this repair requires removing engine from vehicle.
~ If you find the right TimingGuide\Cassette intact\unbroken, you're even luckier: put the ValveCover back on with a new gasket.
3) If you've gotten this far without finding broken TimingGuides, might as well remove the left ValveCover & inspect the left TimingGuide\Cassette.
~ If you find it's broken, this still requires significant repair work, though it does NOT require removing the engine from vehicle.
~ If you find the left TimingGuide\Cassete intact\unbroken, consider yourself blessed; put the ValveCover back on with a new gasket.
4) If you've gotten this far without finding broken TimingGuides, you are being protected by angels;
~ Install new left & right OilPressurized TimingTensioners; old ones are likely "crusty", not keeping the chains tight: rootcause of the noise+damage.
~ Switch from spec 5w30 to 0w30~FullSyn oil &\or install a "PreOiler" if you want to keep this vehicle running longterm.
~ Become OCD about changing the oil+filter every 10k miles or 6mths, which ever comes first.
~ Become OCD about changing the OilPressurized TimingTensioners every 75k miles or 10yrs, which ever comes first.
If you choose to keep driving with TimingChain noise, catastrophic damage is likely to occur, requiring an entirely new engine\vehicle.
Hope this helps.
D

PS: Details of my adventure with the TimingTensioners on a 2001 Ford V6~4.0L~SOHC at
 




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