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Old 02-07-2025, 10:35 AM   #1
jumpsoffrock
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Re: Do all old trucks leak or is there an acceptable amount?

I'm here to piss all of you off lol: I inherited a 1967 C50 dump truck with a bill of sale from 1980 stating a mileage count of 217k miles at time of sale. The bottom of the engine is filthy like it has never been cleaned but none of the crud is wet with oil, it's all dry, the engine burns a quart of oil every 50 miles or so, sounds bad and really needs a rebuild.
This truck is used once every 2-3 months ans started once a month or so.
It sits static most of the time and is parked in the same spot when done being used.
The trans leaks.

Zero leaks from ANY point of the engine whatsoever.
How in Gods green earth does this happen lol

Old pic is from 1990 when it was given to dad as a "gift".
New pic is last year. Good truck.
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Old 02-07-2025, 11:36 AM   #2
custom10nut
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Re: Do all old trucks leak or is there an acceptable amount?

While I was in the Army, we had a Category system to identify “Leaks”.
Cat 1: can be seen but only produces at the touch (slight weeping, very minor)
Cat 2: produces fluid but only dripping (not catastrophic with monitoring)
Cat 3: produces fluid in a steady stream (will lead to failure from loss of fluid).
Many of our trucks leak a little becuse the friction seals are over 50+ years old.
Most leak because the seal contracts faster that the shaft/bearing at shutdown
If you have OCD, you might not want and old vehicle.
My 70 has three minor leaks, that know need to be addressed, (oil pan, trans pan, and power steering box) but I just haven’t yet made the time to change out the faulty gaskets/seal. I do have the new parts on the shelf though
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Old 02-07-2025, 12:24 PM   #3
57taskforce
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Re: Do all old trucks leak or is there an acceptable amount?

This thread made me laugh… mostly at the 350 in my K20 that pushes oil mist out the pcv breather because it’s wore out, it then blows all over the right side of the engine. It’s got the felpro silicone oil pan gasket and new timing cover and rear main gaskets, as well as the felpro silicone valve cover gaskets. It doesn’t really leak any where in any of those places. It also pushes oil out the front china wall but not because of bad gaskets… somedays it’s as good of an air compressor from the bottom end as it is an air pump for powering in the truck if you know what I mean lol. One of these days I’ll get the 6.0 built

It actually still runs pretty good all things considered, doesn’t foul plugs etc, but there is a really nice .030 or so lip at the top of the cylinders…
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Old 02-07-2025, 03:52 PM   #4
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Re: Do all old trucks leak or is there an acceptable amount?

Are the fel-pro blue silicone gaskets gtg?
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Old 02-07-2025, 04:08 PM   #5
Cali72K20
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Re: Do all old trucks leak or is there an acceptable amount?

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Originally Posted by IT Cowboy View Post
Are the fel-pro blue silicone gaskets gtg?
Yes, they really do not require any RTV, I use this with the blue rubber gaskets.

https://www.gasgacinch.com/

For all other gaskets I use this.

https://www.permatex.com/products/ga...et-maker-3-oz/

My truck likes to leave its mark when parked, so I have one of these under it.

https://www.autozone.com/shop-and-ga...ray/475418_0_0

Last edited by Cali72K20; 02-07-2025 at 04:13 PM. Reason: info
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Old 02-07-2025, 05:51 PM   #6
57taskforce
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Re: Do all old trucks leak or is there an acceptable amount?

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Are the fel-pro blue silicone gaskets gtg?
They work pretty good. On the oil pan They recommend silicone across the timing cover and into the front corners. In the rear I believe it’s the same, across the rear lip of the pan and into the corners. I like to put a few very small dabs in the corners of the valve covers as well.
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'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s
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Old 02-08-2025, 01:34 PM   #7
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Re: Do all old trucks leak or is there an acceptable amount?

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Are the fel-pro blue silicone gaskets gtg?
Yes very good if installed correctly. Like a oil filter gasket, a film of oil is good to help squish and also assist release upon replacement. If using on a pan, timing cover or intake, be sure to dab a bit of RTV in the appropriate corners. No gasket will seal those areas. Last point is the front and rear arch of the oil pans. I found them not to be very snug on the 2 pans I attempted to use. I gave up on finding a good fitting reasonably priced pan. A liberal bead of RTV has held well. Last on your statement of using RTV like calk. I did so on a weep of oil in the arch area between pan and timing cover with success. Cleaned with brake cleaner, and run a bead. Smear and crossed my fingers.
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Old 02-08-2025, 02:50 PM   #8
57taskforce
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Re: Do all old trucks leak or is there an acceptable amount?

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Yes very good if installed correctly. Like a oil filter gasket, a film of oil is good to help squish and also assist release upon replacement. If using on a pan, timing cover or intake, be sure to dab a bit of RTV in the appropriate corners. No gasket will seal those areas. Last point is the front and rear arch of the oil pans. I found them not to be very snug on the 2 pans I attempted to use. I gave up on finding a good fitting reasonably priced pan. A liberal bead of RTV has held well. Last on your statement of using RTV like calk. I did so on a weep of oil in the arch area between pan and timing cover with success. Cleaned with brake cleaner, and run a bead. Smear and crossed my fingers.
That’s what Felpro’s instructions say to do with the RTV.
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'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s
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Old 02-11-2025, 03:13 PM   #9
70STOVEBOLT
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Re: Do all old trucks leak or is there an acceptable amount?

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Are the fel-pro blue silicone gaskets gtg?
If you are talking about the PermaDry gaskets, they have torque limiters built in so you cannot over-torque the bolts. I have the valve cover and oil pan gaskets. They are expensive, but worth it in my opinion. They are also reusable, which is nice.
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Old 02-07-2025, 05:58 PM   #10
Shark_13
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Re: Do all old trucks leak or is there an acceptable amount?

I've used a bunch of felpro gaskets on my Jeep. All good.

Another thing I like are the Lube Locker differential gaskets. They are reusable.
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Old 02-07-2025, 07:24 PM   #11
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Re: Do all old trucks leak or is there an acceptable amount?

Some time ago I had a restricted PVC hose on the WMB. Once I replaced the collapsed hose my oil leakage was noticeably reduced.
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Old 02-08-2025, 01:50 PM   #12
dmjlambert
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Re: Do all old trucks leak or is there an acceptable amount?

OK now I'm getting enthused about caulking my engine. 🥓
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Old 02-08-2025, 04:00 PM   #13
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Re: Do all old trucks leak or is there an acceptable amount?

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OK now I'm getting enthused about caulking my engine. 🥓
JB Weld is better....
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Old 02-09-2025, 02:45 AM   #14
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Re: Do all old trucks leak or is there an acceptable amount?

You folks can hate me now but the wife and I took the truck on a drive before I pit it away in the garage this evening around 4 pm. I just went to check on it and say goodnight and there are no drips on the floor. Maybe it is no big deal or doesn’t mean **** but that is nearly seven hours with no leaks showing or at least not showing on my garage floor! I told my wife that she helped me pick out a good one.
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Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.
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Old 02-09-2025, 09:56 AM   #15
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Re: Do all old trucks leak or is there an acceptable amount?

Wake up and smell the gas fumes and motor oil! Now I'm doubly enthused about caulking my engine.
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Old 02-09-2025, 10:05 AM   #16
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Re: Do all old trucks leak or is there an acceptable amount?

Sometimes it's not just the gaskets. I've had rear cam plugs leak, the intake manifold bolts can leak (easy fix usually), and if you have a plastic line running to your oil gauge it can leak like crazy!

I struggle with transmission leaks more than anything.

Good luck, Rg
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Old 02-10-2025, 02:38 PM   #17
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Re: Do all old trucks leak or is there an acceptable amount?

Well, my truck sat in the garage for 17 hours on Sat. night before I checked on it again and there were no drips on the floor. I backed it out into the drive Sunday morning and it then put one small drop on the ground and I guess that was enough to squeeze the drop out of it lol. Again I don't think there is anything worth messing with now and with my luck I would not get something re-sealed and make it worse.
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Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.
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Old 02-10-2025, 06:33 PM   #18
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Re: Do all old trucks leak or is there an acceptable amount?

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Well, my truck sat in the garage for 17 hours on Sat. night before I checked on it again and there were no drips on the floor. I backed it out into the drive Sunday morning and it then put one small drop on the ground and I guess that was enough to squeeze the drop out of it lol. Again I don't think there is anything worth messing with now and with my luck I would not get something re-sealed and make it worse.
If that's all you have I wouldn't mess with it.
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Old 02-11-2025, 01:51 PM   #19
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Re: Do all old trucks leak or is there an acceptable amount?

A drop every couple weeks is acceptable (IMO) but a few drops every week isn't.
If your truck falls into the second category, get the "easy" gaskets replaced asap. The rear main seal leak might decrease (or even stop) if you swap out the oil to "high mileage" type which has added 'seal conditioners'. If that doesn't stop the rear main leak then either live with it or have the pan gasket and seal replaced.
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Old 02-11-2025, 03:28 PM   #20
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Re: Do all old trucks leak or is there an acceptable amount?

I think I read somewhere to put a dab of rtv on the edges under the 4 bolt carrier when replacing the neoprene main seal.
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