Rear Engine Oil Leak on Gas IH 674 (C-200 Engine)

Hi, everyone! I am working on solving a bad oil leak on my
gas IH 674. Engine oil is dripping from the bell housing.
I will go through between one and two quarts of oil per day.

I have the tractor split, thinking that the problem would
be the rear main seal. However, this tractor does not have
a rear main seal that is held within a retainer like the
diesel models.

How am I supposed to remove the rear main seal? My
shop manual goes through a long explanation of how to
split the tractor and then simply says that the rear oil seal
can be removed after collapsing same. What does that
mean?

Also, is there anything else that I should be looking at
that could be causing this leak? Could it be a leak
between the oil pan and the engine block or rear main
bearing caps? How would I go about fixing that, if so?

I am going to try to post a picture of the rear main seal in
my tractor and a picture of what my shop manual says.

Any help is appreciated! Thanks!

I use two drywall screws to pull the seal. Drill two SMALL holes in the seal case about two inches apart. Now thread the screws in the holes about 1/2 inch deep. Use two pair of side cut pliers, one on each screw and pry against the crankshaft face using even force on each plier pair to pull the seal out.

Poke a couple of holes across from each in the steel face of the seal with a punch awl (doesn't make chops like drilling) and work it out with an auto dent puller.



For LARGE seals, one can use a large ''pole barn screw'' and a larger slide hammer.

That shiny thing around the crank is the seal.
See responses below how to remove.

If the crank seal surface is bad now is a good time for the installation of a speedi sleeve. Google speedi sleeve installation. Stan

Thanks everyone for the advice! Now my next question: if I replace the seal and the leak doesnt stop, are there any other seals or gaskets that could fail and cause this problem?

My question is did you clean up that area on the back of the engine before you took that photo? If not that area above the crank does not look like that seal was leaking two quarts a day. The spaces on either side of the main bearing cap have grooves that sealing packings are installed in. Those could leak, also the back of the oil pan. The expansion plug on the left is the back of the bore for the camshaft that is a potential oil leak area but that rarely happens.
How is the engine otherwise as far as wear much crankcase blow-by out of the vent tube? Notice much oil burning, blue to gray smoke out of the exhaust? Just seeing if your engine may be using some of that oil instead of leaking all of it.
FYI, collapsing the seal would be driving the outer ring that protrudes out past the back of the engine in towards the crankshaft. This would be done with a dull chisel, you would probably want some type of a protective shim between the seal and the outside of the crank OD. Doing this in 3 or 4 places around one half of the seal releases the press fit for removal. The screws, as mentioned, is a common method.

Thank you, Used Red MN. I did not significantly clean it up, although I did take off the bell housing plate that is mounted between the flywheel and the engine block to get a better look at the seal, and I removed some trash and hay that had somehow accumulated in there.

My thought was the same as yours: it does not look like the rear main seal is actually leaking that bad, if at all. I did an in-frame overhaul on this engine in 2022 (my first one), and the engine starts and runs great, and it has a lot of power. It does not smoke. I know it is leaking bad, though, because it accumulates a huge puddle under it. I definitely believe that it will leak 1-2 quarts per day.

When I bought it in the spring of 2022, it only had compression on two cylinders. I replaced the valves (two were completely rusted out and the remnants of the valves had destroyed two pistons), had the head milled, and replaced the pistons and crankshaft bearings. I had a friend who is a mechanic help me roll the rear main bearing in place, and I am worried that we might have messed something up in terms of sealing when we were messing with the main bearing. We never replaced the rear main seal because I never split the tractor. I do not recall installing any sealing packing on top of the rear main bearing cap, and if so, I guess that would be the problem. It is also possible that my friend installed something there and I do not remember it.

Should I fix that by dropping the oil pan once I get the tractor back together, removing the rear main bearing cap, and resealing it? What packing should I use there?

Thanks again for your help!

Did you replace the seal when you replaced the rear main brg. The main bearing cap contains the lower half of the seal bore, removing the cap may have disturbed the position of the seal. The seal should be installed after the bearing cap is installed. Hopefully your friend did replace any packing that goes between the side of the bearing cap and the block.
These are just some thoughts on the subject, I don't know how accurate they might be.

I did not replace the rear main seal after removing the rear main bearing cap when I rebuilt the engine. That is why I believed, at least before splitting it, that the rear main seal was what was leaking now (because it had been displaced by the removal of the bearing cap).

Does anybody know what packing is supposed to go beside the rear main bearing cap?

Again, my shop manual only has this to say about the rear main bearing, and it does not say anything about packing that I can find (see the attached image).

I have also attached a picture of the seal kit that I have, but now I am not sure if this is the correct kit because it has the retainer gasket, which apparently is only used for diesel models.

Maybe both engines use the same seal. Are those two black round objects possibly the packing that goes in a channel between the block and main bearing cap?

Most of the old IH tractors that used a single piece seal already have a wear sleeve for the crank. My 806with the D-361 engine has them and something else we had apart did also. 3406 Cat uses a wear sleeve with the rear main seals also. If it had the old rope seal then it would not need one since you roll the rope into the groove with a smooth shaft till you have worked all the rope into the groove and yes the crank would turn a bit stiff at first till the seal wore in and it is oiled well at installation. As for your seal collapsing I would worry about useing a chisel so as not to scar up the seal bore and have it leak by the OD of the seal. I would drill it or punch it and pull it by some of the other means described by the others. As for the wear sleeve if it has one that can be a bit of a different animal with the crank in the block. It is harder to get a pull on since it is just a thing strip of steel around the crank. When the crank is out I just tap them around till they are loose enough to slide off. In the block it is needed to see if you can get a thin jawed puller in behind the sleeve to hook onto the edge of the sleeve and pull it. Pay attention to the wear sleeve when you install it it will have a chamfered edge to it one on the outside and one on the inside at the opposite edge The one at the inside goes on first. This helps allow it to start on the crank and the one at the outside helps with the seal starting on the sleeve when the seal is installed. I use the old enlarged sleeve to push the new one on the crank with a plate of steel and bolts in the crank for the flywheel. Once flush if it needs a bit more I just tap the edge of the old sleeve against the new one. You are only looking for a few thousandths to smooth the chamfer at the crank for the seal. then I start the seal with it well oiled and some on the sleeve hold it tight with the same plate and push it in with the bolts again. Then may need to tap it with the old seal as a cushion when doing so. A sealer may need to be used on the sleeve and seal at installation. Take your time don't try to rush it and pay close attention to things being aligned right in the start of each operation. hand tighten the bolts to pull the sleeve and seal in if it acts wrong stop and check things out.

(quoted from post at 19:00:39 12/10/23) I use two drywall screws to pull the seal. Drill two SMALL holes in the seal case about two inches apart. Now thread the screws in the holes about 1/2 inch deep. Use two pair of side cut pliers, one on each screw and pry against the crankshaft face using even force on each plier pair to pull the seal out.

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I have removed many seals using that method.

I skimmed this, and didn't see a mention of the valve cover gasket. Just looking at the oily pattern, it looks like there is a torrent coming down from above. steve

Also, that cam gallery plug that Used Red mentions, looks buggered, but it could just be the photo. There is pressurized oil behind that plug. steve

(quoted from post at 14:17:07 12/11/23) I skimmed this, and didn't see a mention of the valve cover gasket. Just looking at the oily pattern, it looks like there is a torrent coming down from above. steve

Click to expand...

Yep, I was going to mention that.