4.7ltr problems

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Joined: July 28th, 2014, 10:08 am

4.7ltr problems

Unread post by jimrobinsonau » December 16th, 2014, 8:16 pm

hi! got a noisy 4.7ltr which is using water also. firstly the water problem i think is a head gasket. can not find any leaks and a pressure test shows a leak in the system. the motor runs rough also when i first start it up.
o.k. easy fix is to take the heads off and get them checked/machined and replace them, but the noise has me worried. i don't know much about these over head cam engines. when the engine is cold it makes a rattling noise. at first i thought it was a tappet as the noise would go away when the engine was hot, but it comes back when you rev the motor up to 3000rpm or more. a mate said it was the piston. ( piston slap ) do these engine suffer from piston problem? if i was sure it was the tappets then i would rebuild the heads, but my mate has thrown doubt into my thoughts as to what the noise is. the motor has done 200,000kms and has ran hot a couple of times up around the 120 degree mark for a short time only of a few minutes. any idea's
my thought is do i just buy another motor, do a full rebuild on this one or jut do a head job as i first planned.
whats your thoughts considering the engine rebuild is $6,000 and heads are $2000 and a good used motor i have not been able to find so far.
thank you

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Posts: 210
Joined: November 7th, 2011, 1:32 pm
Location: Wallerawang, NSW

Re: 4.7ltr problems

Unread post by Clarkey16 » December 22nd, 2014, 4:34 pm

If you are handy with the tools replace the suspect head gasket your self. Then see how it runs.
No point spending big $$$ if your up for a replacement engine.

Just remember to mark the timing/cam chain's & take lots of photos as you go.

Here is a link to the service manual.
http://www.ausjeepoffroad.com/FSM/WJ_Gr ... ee.pdf.zip
Yes I did! Built with spanners not chop sticks!

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