8.3 oil leak, crank seal or timing cover?

Topic: 8.3 oil leak, crank seal or timing cover? (Read 909 times) previous topic - next topic

8.3 oil leak, crank seal or timing cover?

February 26, 2024, 01:30:29 pm

I have had some pretty good oil dripping off my engine in the back of my engine compartment. Cleaned and detailed the whole area (what a mess—I was covered with slug and oily debris after), changed the oil and put a little less in in case it was just blowing out the extra as mine was very full. Now it looks like some oil is coming off of behind the lower pulley which I am guessing is the crankshaft seal or perhaps the cover behind the pulley, , which I believe is the timing cover. I did tighten all the bolts around the timing cover, and the ones that are hard to get to behind the pulley.
Have some had experience replacing the crankshaft seal or timing cover gasket? Wondering if these are common to leak and how hard it is to replace. It looks like it would be hard to get a puller in there to pull that lower pulley. Can it be pried off? Any advice on this is highly welcomed.
Curtis

'95 U280 36', 8.3

Re: 8.3 oil leak, crank seal or timing cover?

Reply #1 – February 26, 2024, 02:28:27 pm

2002 U320 ISM Oil leak repair

Re: 8.3 oil leak, crank seal or timing cover?

Reply #2 – February 26, 2024, 04:07:29 pm

Quote from: NevadaBornRvR – February 26, 2024, 02:28:27 pm

2002 U320 ISM Oil leak repair

Like the link for info on my ISM but much different from 8.3

Re: 8.3 oil leak, crank seal or timing cover?

Reply #3 – February 26, 2024, 04:25:05 pm

I was just about to mention that....im not familiar with the ISM or how different than the 8.3 on my '95

Re: 8.3 oil leak, crank seal or timing cover?

Reply #4 – February 26, 2024, 05:11:19 pm

Curtis,

I'm not suggesting (at this early point in the discussion) that you will need to replace the crankshaft seal, but if you DO finally decide to go that route, you might think about having a new harmonic damper (balancer) on hand. After 30 years the rubber in the OEM damper is probably getting kinda dry and brittle. If you shop around online and buy it ahead of time, you can probably get the best price available in the current market.

See the (old and dated) discussion below for more info:

Cummins Vibration Damper

Re: 8.3 oil leak, crank seal or timing cover?

Reply #5 – February 26, 2024, 05:18:07 pm

I would first take your breather tube off at the top of the valve cover and give it a good cleaning,if it is partcially blocked it could
cause excessive crankcase pressure and cause a leak,and make sure you know exactly what/where is leaking,could be your hyd.
pump.
Balancer is easy to change,replaced mine a few years ago.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #6 – February 27, 2024, 08:23:00 am

I thought my 8.3 oil leak was from the crank seal, turner out to be a cracked timing cover, not really common on the 8.3, but not unusual.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #7 – February 27, 2024, 12:58:40 pm

Mark. Was it a cracked timing cover (steel) or a cracked timing "case" ( aluminum). ?
My oil leak in that area was apparently a failed OEM gasket between timing case and the engine block. Permatex spray seal helped. 🤞🤞.
And how did you fix yours ??

Re: 8.3 oil leak, crank seal or timing cover?

Reply #8 – February 28, 2024, 08:10:37 am

I was on the road, pulled into a campground in Wichita and saw the oily mess. Thought it was the crank seal. Went to the cummins dealer in the morning and found out it was the alum. timing case. Lots of info on this on the interweb, most deals with the 5.9 cummins. For some reason when it happens on the 8.3 the damage is not as severe as on the 5.9. This happened to me 5 years ago and I have wrecked so other things during that time my details may not be exactly right. Not a quick easy fix, timing gears and everything in front of the housing has to be removed.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #9 – February 28, 2024, 03:42:23 pm

Quote from: mark f – February 28, 2024, 08:10:37 am

I was on the road, pulled into a campground in Wichita and saw the oily mess. Thought it was the crank seal. Went to the cummins dealer in the morning and found out it was the alum. timing case. Lots of info on this on the interweb, most deals with the 5.9 cummins. For some reason when it happens on the 8.3 the damage is not as severe as on the 5.9. This happened to me 5 years ago and I have wrecked so other things during that time my details may not be exactly right. Not a quick easy fix, timing gears and everything in front of the housing has to be removed.

I hear the timing case seal is a bear to do, requiring removal of the cam, etc.

I did replace my vertical portion of the breather hose. I guess the first, simplest thing to do is make sure it is clear all the way into the valve cover, or wherever it starts...I'll go look.

And thanks Chuck for the heads up on the balancer, and getting a new one.

If I do need to replace the crank seal will the timing cover need to come off? I suppose it's best to replace the cover gasket anyway while in there? I think it's easy to get to once one gets the lower pulley off.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #10 – February 28, 2024, 04:03:18 pm

Quote from: craneman – February 26, 2024, 04:07:29 pm

Like the link for info on my ISM but much different from 8.3

Doesnt matter which motor for the most part. The process and basic tools... THis will give a general idea of the work, up to you to decide if you have the skills to accomplish

Re: 8.3 oil leak, crank seal or timing cover?

Reply #11 – February 28, 2024, 04:12:45 pm

I hear there may be a newer better stiffer timing cover I should use for the 8.3....is this true?

Re: 8.3 oil leak, crank seal or timing cover?

Reply #12 – February 28, 2024, 04:27:29 pm

If you take the valve cover off there is a screen where the breather hose goes in,you said you just changed the oil,so the oil
leaking now should be very clean,is that the case? I found some videos on installing the front seal,just do a search.
Where are you located?

Re: 8.3 oil leak, crank seal or timing cover?

Reply #13 – February 28, 2024, 04:51:13 pm

Quote from: campipilot – February 28, 2024, 04:12:45 pm

I hear there may be a newer better stiffer timing cover I should use for the 8.3....is this true?

I've heard the same thing. It's supposed to have some structural support where the OEM didn't. And don't forget the improved rubber impregnated gasket for the timing case IF... you go that route.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #14 – February 29, 2024, 08:30:34 pm

Quote from: John44 – February 28, 2024, 04:27:29 pm

If you take the valve cover off there is a screen where the breather hose goes in,you said you just changed the oil,so the oil
leaking now should be very clean,is that the case? I found some videos on installing the front seal,just do a search.
Where are you located?

Located in Boulder City, NV by the Hoover damn, near Las Vegas

Re: 8.3 oil leak, crank seal or timing cover?

Reply #15 – March 05, 2024, 10:42:48 pm

Ok. I replaced the timing cover gasket and front crank seal.

I ran a thin coat of RTV on both sides of the timing cover gasket. The crank seal does install from the inside of the timing cover. We did NOT have the crank seal install tool. I thought the kid helping had rented one but hadn't. I carefully with something the same diameter tapped it in flush with the back. Then gently tapped around until it was the exact depth I had observed the old one was, which was one millimeter in from the outside.

The harmonic balancer looked ok....as far as I can tell??? The outer side the rubber was flush all around. The other side the rubber was rounded out about a mm +. It looked like that's how it came, I don't know? The rubber wasn't cracked and dry. I hadn't had time to order another and it's not to hard to get off, with my powerful impact gun at least...glad to have that as it's hard to avoid turning the crankshaft getting bolts off.

I've run it about an hour and now leaks from there. Good.👍 A bit it looks from some hydraulic hoses, but minor.
The hydraulic fans look to be leaking some especially my forward one....and still quite the build up greasy sludge around the fan area, even though I'd thought I'd degreased and power washed the engine bay well. Man that stuff is stubborn messy buildup.
I guess there are seals in the fan motors that I should replace? Another very messy project to pick your folks' brains about what to do.

Thankfully, so far my timing case seal looks ok, gratefully!!

Thanks

Curtis

Re: 8.3 oil leak, crank seal or timing cover?

Reply #16 – March 05, 2024, 10:50:40 pm

Just finished resealing my fan motors. Not a complicated job just really messy. Pulled mine out of the bottom of course you need to drain the hydraulic system, and the cooling system if you have the 2 1/2" pipe running under the fans. The seals for mine are 20x30x7 MM.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #17 – March 29, 2024, 02:20:09 am

Quote from: bbeane – March 05, 2024, 10:50:40 pm

Just finished resealing my fan motors. Not a complicated job just really messy. Pulled mine out of the bottom of course you need to drain the hydraulic system, and the cooling system if you have the 2 1/2" pipe running under the fans. The seals for mine are 20x30x7 MM.

I wonder if those seals are pretty standard....id sure like to have them before I do the job. I believe the 20x30x7 is what craneman used to in his write up. My coach is a '95 U280 8.3. Does anyone have experience with the fan seals on my year???
I just changed the fluid and filter in the fan hydraulic system ... bummer to have to drain it again. I suppose you drained the reservoir , then when the hoses were disconnected a fair bit came out as well? hope the radiator pipe isn't in the way requiring removal of the radiator!!!
I did get under there and scrape a lot of the sludge away...now to pressure wash it and use more degreaser. I wish my pressure washer heated the water as I imagine that would help...thinking of using hot water from the coach for the pressure washer...and find somewhere other than my fairly clean driveway to do it!

Any advice welcomed! Thanks
Curtis

Re: 8.3 oil leak, crank seal or timing cover?

Reply #18 – March 29, 2024, 09:35:50 am

If you are not going to pull the radiator, you will need to drain it and remove the pipe that runs underneath the fans. Fluid wise you will end up with 4 or so gallons of oil and 10-15 gallon of coolant. As far as hoses they will drip as long as they are disconnected. I went to the local Hydraulic shop and got plastic caps and plugs for mine, helps manage the drip and dirt getting in. They are not expensive. The fittings are JIC sizes 5, 6, 10, 12 IIRC. Those seals are likely the same, they are available all over AMAZON for cheap so if they are not the right ones you can just send them back. No need to take the motors apart the shaft seals go in fron the outside. Pm me with your # if you like.

Re: 8.3 oil leak, crank seal or timing cover?

Reply #19 – April 15, 2024, 09:34:38 pm

Ok fortunately I do not have the pipe running below my radiators. Drained the hydraulic tank, disconnected the lines, let oil drain and took the messy fans and motors out. (Yes still quite messy after pressure washing and using degreaser a couple times, making myself and everything around quite the laughable mess as well).

Unfortunately the seals I bought are not what I need...... anyone see this pump and seal and replaced theirs??

I had ordered the 20x30x7mm seals others have mentioned but apparently I have different motors and seals.

Mine weren't leaking horribly, I was just trying to get most of the bigger leaks taken care of. I'm reluctant now to mess with this without some guidance....inclined to put it all back together and try some power steering stop leak unless someone speaks up with advice on these pumps/seals.

'93 grand villa U280, 8.3

Re: 8.3 oil leak, crank seal or timing cover?

Reply #20 – April 15, 2024, 09:59:20 pm

Same as Chuck's...

Re: 8.3 oil leak, crank seal or timing cover?

Reply #21 – April 15, 2024, 10:21:53 pm

Looks like a 20 47 7 seal which are available. I'd pull one out, examine configuration and order new ones. Hard to say why they are different from others, suspect some casting variability may have called for larger seals or something of that order. Personally, no way I'd reassemble it without replacing seals. You might take em by a hydraulic shop if uneasy with process, my luck with these shops solving problems in short order is 100%.

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