Oil pan gasket change 5.7 L31

[A97obs]

There's probably some youtube vids for the 2wd. I watched a couple on doing this on a k1500. You can either lower the front diff, or remove the oil pump, and the pan will come out. Might have to take off oil filter adapter too.

My problem is I kind of want to pull it and pressure wash the engine bay and go through the engine top to bottom, which leads me to project creep. This is the third oil sealing gasket on it that needs to be replaced and it is a mess down there.

Maybe Get it on a hoist and clean it up ! Ease of access

Mines isn’t to bad it’s a Cali Truck, I have had to do everything on my back in a driveway the hard way, the lifting the lowering the C notch the new fuel pump .. I mean I’ve replaced all the suspension components up front and power washed down under the cradle 50 times it seems like over summer , so not to greasy besides the crossmember and starter has some sludge

 

[A97obs]

'Tis true, I did exactly that and without disturbing the oil pump/filter assembly - though I probably would if doing it again. I did IIRC remove the dipstick tube.
That was on a C - Ks I think are different. The 'certain position' is I think written somewhere but I can't remember where or whether I jiggled with mine or it was conveniently stopped in the correct position (unlikely). See photo below from when this was done but I'm not saying the crank is in the position it had to be in.
So it can be done without lifting the block and with minimal disturbance to anything else on a 2WD but it is a writhing wriggling effort to do it. Removing the oil pump/filter assembly would make it easier - I had to have the pan at a tilt to clear it. The easier it can be offered up, the less chance of displacing the sealant improving the chances of a leak-free result. For sure, it can be done without lifting the motor. Note, I removed the pan. Whether the gasket can be changed with the pan dropped but still 'there' I don't know but only possible I'd guess if the sealing surfaces can be accessed well enough for cleaning.

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Im not to keen on seals and other particulars but These have a one piece rear main seal on the L31 design right ? that’s easily changed with the trans pulled back or dropped down ? For the notorious rear seal leak? Or is that the two piece design ?

I remember when we did my nv3500 clutch on my s10 we had trans down and the 2001 4.3 vortec had a once piece seal to yank out with a seal puller

I need to do that also I’m not completely sure it’s leaking some but likely is at 200k .

 

[A97obs]

I have heard that there's a certain position that the crankshaft has to be in, and then you can pull the pan w/o jacking the engine up. @Pinger did it that way on his '99 C2500 Burb. On my other C1500 Burb I had to jack the engine up because the pan's windage tray caught on the baffle attached to the main bearing caps. Of course you have to pull the motor mount bolts to do this. I used a bottle jack with a wood block on it, with a half round notch and jacked on the crank snout. Had the balancer and pulley off cause I was replacing timing set.

Would make sense to change the oil pump and pickup at the time
The pans out of the way would you agree? , considering even if one had great oil pressure on a high mileage motor ?

 

[A97obs]

The 'certain position' is I think written somewhere but I can't remember where or whether I jiggled with mine or it was conveniently stopped in the correct position

So there is a write up on knowing what the position the crank should be in without visually seeing it ?

It looks like the crank journal’s are at a half/half 50/50 down the center of the pan the way the photo shows you took

 

[A97obs]

On my other C1500 Burb I had to jack the engine up because the pan's windage tray caught on the baffle attached to the main bearing caps.

Any particular components or anything up top in the bay wiring / hard lines / ac stuff / anything needing removed or loosened prior to the short engine lift ?

 

[kylenautique]

I did this on my 98 K1500. Not the most fun I've had... The cross member below the pan gave me enough clearance to get the old gasket out. Now, my truck is lifted so I can't confirm if this is possible in stock form. The hardest part is getting the new gasket around the oil pump pickup. I had to get a little creative with applying the RTV. I always do the 4 corners top and bottom, and a light bead on the front and rear valley. I had to use a screw driver to get the RTV where it needed to go. I reinstalled and didn't touch the truck for over 24 hours. It worked great. Its helpful with 2 people so one can move the pan around while the other installs the gasket. I had 75k miles of no leaks from the pan afterwards. Just take your time.

 

[Pinger]

Did or does the trans being attached to the motor cause any aggravation in the angle or process of the lift or hassles with the trans cross member tilt? Or the trans mount ? or anything along the drive line causing stress points ?

IIRC - and it is four years since I did this, I either removed or maybe just slackened the steel shield twixt block and trans - just for some more wriggle room.

 

[Pinger]

So the pan on a C series 1500

C2500 here.

can be pulled out without lifting it just to clarify? But the crank still needs to be on a certain rotation point to pull the pan down and back ?

Yes. But IIRC once the pan is lowered it can be seen where the pan and crank foul and the crank manipulated.

Does the pan just drop or does it literally come all the way out and able to set it aside ?

It will drop onto the chassis/frame than have to be slid rearwards until clear of chassis enough for complete removal. With the oil pump/filter still in place I had to 'twist' it also so that one edge was lower than the other to extricate it.

 

[Pinger]

This is Just a random extra thought ! Should the pan be replaced in any event just for ease of maybe uneven surface or reusing a 25-30 year old pan .. any upside to 50/50 doing a new pan at the same time

Your call. I refitted the original.

What gasket brand / material is the go to of choice ?

Felpro - and as per ODB's post, it includes assembly dowels. If you do the job exactly as I did, you won't be able to utilise all the dowels bringing the pan in at a slant to clear the oil pump/filter. That may be enough to persuade you to remove the oil pump/filter.

 

[Pinger]

Im not to keen on seals and other particulars but These have a one piece rear main seal on the L31 design right ? that’s easily changed with the trans pulled back or dropped down ? For the notorious rear seal leak? Or is that the two piece design ?

One piece I think on a L31 - but I wasn't for touching it.
Bear in mind that the pan seals to the front (timing) cover. I can't recall if sealant is used there (I think it is) as well as the gasket corners or, if it has to be slackened to remove/refit the pan. I think it's the other way around ie, the pan has to be dropped a touch to remove/refit the cover but if the cover has to be disturbed it's a 'single use' item.