Bad Leak... front main seal? - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 07-28-2003, 01:17 PM
Posts: n/a
Bad Leak... front main seal?

I have a pretty major oil leak from the front of my 258.
It looks like a rear main seal type leak, but in the front. could it be the front main seal?
i am not real familiar with the oil gaskets and seals on a 258, as most of my engine experience is on a sb chevy.
is there a front main seal?
someone told me something about a easily replacable crankshaft seal that could have gone bad.

I cant say i like the oil leak, but it is expected on a 82 jeep. but this is getting bad. i go thru a quart a week. and homeowners cringe when they see my jeep coming down the road leaving big black stains everywhere i stop.

i have to do a waterpump tonight anyway, so i thought i might as well try and fix this leak while i am up there.

any ideas or things to look for or to do?

how hard is it to get to the gaskets and seals on a 258?

i know on a small block chevy you just drop the oil pan, scrape off the old and pop on the new and you are back in business.

well i wish, but doubt, this is so easy.

what parts should i buy? and are there any tricks to a 258 water pump install?
Sponsored Links
post #2 of (permalink) Old 07-28-2003, 04:50 PM
Posts: n/a
Re: Bad Leak... front main seal?

Hi Ken,

Replacing the front main seal and water pump on a 258 is pretty straight forward.

Of course you need to remove the belts, hoses, the fan and the fan clutch to get to the water pump. I think the pump takes 4-5 bolts, so just take them off and carefully pry off the old pump. Before you install the new pump make sure that the new pump is made to rotate in the same direction as the old pump.

For the timming chain you need to remove the harmonic balancer. You may or may not need to remove the radiator so you can pull the balancer out. The timming chain cover takes 7-8? bolts on the front and 5 bolts on the bottom where it meets with the oil pan. You might have to loosen all the oil pan bolts in order to separate the oil pan from the timming chain cover. If you do have to drop the oil pan, might as well put a new oil pan gasket. Carefully pry the cover off, clean mating surfaces, drive out the seal, install the new seal, and install.

The water pump and front seal replacement on the 258 is a pretty easy, straight forward process. I say its easy because I helped change the water pump on a few newer Mitsubishis and Toyotas and they are a royal pain to do. You practically need to take half the engine apart.

Hope this helped,

post #3 of (permalink) Old 07-28-2003, 08:03 PM
Join Date: Jul 2002
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Bad Leak... front main seal?

Well if you think it's the front crank seal, it's not difficult to replace. As zmanmike said, you'll have to remove the stuff on the front of the motor and removing the radiator helps free up room to work, but the front crank seal can be removed without removing the front cover...or at least the one I installed when I did my timing chain could be removed without removing the cover. I know, I had to replace mine because I somehow tore it when putting everything back together after the timing chain replacement.
Stickybones is offline  
Sponsored Links
post #4 of (permalink) Old 07-29-2003, 06:47 PM
Join Date: Oct 2001
Location: Brooklyn, Maryland
Posts: 105
Thanks: 0
Thanked 0 Times in 0 Posts
Harmonic balancer seal

My impression is as the others. I wanted to add one thing. There are repair sleeves for the snout of the harmonic balancer. The seal can wear the snout enough that a new seal will only work so well before leaking again. The sleeve should be under $20. I've used them on a few SBC. Only makes sense to me that they're offered for other applications.
Manifold is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome