258 Rear Main Seal

Well atleast i think its the rear main seal. I've got alot of oil leaking from
either the oil pan or the main. My question is how hard is it to change. Can i
just drop the pan and drop the crank down enough to change the seal? I also
hear what sounds like a bearing <sp>. The engine sounds normal at any speed
when its cold but once it warms up you can hear it...eh who knows. The good
news is I pick up my new Rubicon on monday.
haha.

Brian
88 YJ

I doubt your rear main is leaking unless the crankshaft has some slop in it.
Yes its fairly easy to change its two piece.
KH


"Wranglerjeep1" > wrote in message
...
> Well atleast i think its the rear main seal. I've got alot of oil leaking
> from
> either the oil pan or the main. My question is how hard is it to change.
> Can i
> just drop the pan and drop the crank down enough to change the seal? I
> also
> hear what sounds like a bearing <sp>. The engine sounds normal at any
> speed
> when its cold but once it warms up you can hear it...eh who knows. The
> good
> news is I pick up my new Rubicon on monday.
> haha.
>
> Brian
> 88 YJ

Standard response is "your valve cover gasket is leaking" The 258 is
NOTORIOUS for leaking out the back of the cover. It mimics a bad rear
seal nicely. At least one of the regulars on the NG actually replaced
the rear seal TWICE before he got at the valve cover gasket.

Wipe off the back of the head and block or, better yet, power wash it at
the self service car wash. Stick a paper towel down behind the head,
between the head and the firewall. Drive for 5 miles, bets are that it
will be completely soaked in oil.

Fixing it is simple but touchy. 3 basic choices: stock platic cover with
RTV sealant, plastic cover with expensive foam/cork gasket, or aluminum
cover with cork gasket. My personal choice is to clean cover and gasket
squeaky clean (final cleanup with carb cleaner spray), heavy bead of
RTV, set the cover on withing 5 minutes so it is still tacky, let it sit
for at least 24 hours so it cures. Works for me, lots of discussion on
what works for others.

Cheers.

Wranglerjeep1 wrote:
> Well atleast i think its the rear main seal. I've got alot of oil leaking from
> either the oil pan or the main. My question is how hard is it to change. Can i
> just drop the pan and drop the crank down enough to change the seal? I also
> hear what sounds like a bearing <sp>. The engine sounds normal at any speed
> when its cold but once it warms up you can hear it...eh who knows. The good
> news is I pick up my new Rubicon on monday.
> haha.
>
> Brian
> 88 YJ

HaHa...yeah I've replaced the valve cover gasket about 3 times since i've owned
this jeep.....I'm positive its not the valve cover. The back side of the head
is dry. I crawled under and actually watched it drip from the back of the pan.

Brian

http://www.neow.org/rms1.html
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Wranglerjeep1 wrote:
>
> HaHa...yeah I've replaced the valve cover gasket about 3 times since i've owned
> this jeep.....I'm positive its not the valve cover. The back side of the head
> is dry. I crawled under and actually watched it drip from the back of the pan.
>
> Brian

Also check oil filter adapter. The adapter has 3 o-rings and a leak there
will let oil blow back to end of engine and drip of. Depends on age.

odd-inge

"Wranglerjeep1" > wrote in message
...
> Well atleast i think its the rear main seal. I've got alot of oil leaking
> from
> either the oil pan or the main. My question is how hard is it to change.
> Can i
> just drop the pan and drop the crank down enough to change the seal? I
> also
> hear what sounds like a bearing <sp>. The engine sounds normal at any
> speed
> when its cold but once it warms up you can hear it...eh who knows. The
> good
> news is I pick up my new Rubicon on monday.
> haha.
>
> Brian
> 88 YJ

99% of the time the leak is from the valve cover on those engines. The
engine is tilted and has a nice slot that runs right down the middle of
the back so the oil has a free channel to run right off the bottom
'seal'.

To check, warm up the engine and take a clean rag and wipe the rear of
the head just below the valve cover. If you find oil, you have found
the leak.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Wranglerjeep1 wrote:
>
> Well atleast i think its the rear main seal. I've got alot of oil leaking from
> either the oil pan or the main. My question is how hard is it to change. Can i
> just drop the pan and drop the crank down enough to change the seal? I also
> hear what sounds like a bearing <sp>. The engine sounds normal at any speed
> when its cold but once it warms up you can hear it...eh who knows. The good
> news is I pick up my new Rubicon on monday.
> haha.
>
> Brian
> 88 YJ

"RoyJ" > wrote in message
ink.net...
> Standard response is "your valve cover gasket is leaking" The 258 is
> NOTORIOUS for leaking out the back of the cover. It mimics a bad rear
> seal nicely. At least one of the regulars on the NG actually replaced
> the rear seal TWICE before he got at the valve cover gasket.
>

I resemble that remark.

Replacing the rear main is easy enough. On my CJ, I had to remove a motor
mount to gain access to a few pan bolts, but that is easy. All one needs to
do is support the motor with a floor jack, take the pan off, loosen the
bearing caps, remove the rear bearing cap and use a brass punch to push the
upper seal out of the block and set the new seal flush, replace the lower
seal that is in the bearing cap that you removed, and put everything back
together. The bearing cap bolts must be tightened in the correct sequence,
and the pan gaskets are somewhat of a bitch because there are several that
have to be overlapped and stacked right, but basically it's an easy job.

Probably NOT the problem though. I encourage you to look at the valve cover
gasket first.

90 times out of a hundred, it's the VC gasket. You may be one of the lucky
10 that actually needs a rear main seal.




"Wranglerjeep1" > wrote in message
...
> HaHa...yeah I've replaced the valve cover gasket about 3 times since i've
owned
> this jeep.....I'm positive its not the valve cover. The back side of the
head
> is dry. I crawled under and actually watched it drip from the back of the
pan.
>
> Brian

I'm inviting you over for pizza and beer if my rear main seal starts
leaking Jeff.

Jerry

Jeff Strickland wrote:
> "RoyJ" > wrote in message
> ink.net...
>
>>Standard response is "your valve cover gasket is leaking" The 258 is
>>NOTORIOUS for leaking out the back of the cover. It mimics a bad rear
>>seal nicely. At least one of the regulars on the NG actually replaced
>>the rear seal TWICE before he got at the valve cover gasket.
>>
>
>
> I resemble that remark.
>
> Replacing the rear main is easy enough. On my CJ, I had to remove a motor
> mount to gain access to a few pan bolts, but that is easy. All one needs to
> do is support the motor with a floor jack, take the pan off, loosen the
> bearing caps, remove the rear bearing cap and use a brass punch to push the
> upper seal out of the block and set the new seal flush, replace the lower
> seal that is in the bearing cap that you removed, and put everything back
> together. The bearing cap bolts must be tightened in the correct sequence,
> and the pan gaskets are somewhat of a bitch because there are several that
> have to be overlapped and stacked right, but basically it's an easy job.
>
> Probably NOT the problem though. I encourage you to look at the valve cover
> gasket first.
>
>
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/