2000 K3500 4x4 CC DRW

cool_as_crap said:

And bad news...
During the move my oil pressure started dropping, down to 0 at stops at operating temp. The pressure sensor doesnt display typical signs of going bad unfortunately. Though the engine sounded fine and oil pressure still built up to about 20psi when driving, like 2200 rpm.

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Christian Steffen said:

This sounds exactly like the symptoms of my 454 when it was on its way out. Be careful how much longer you run it, otherwise you may not be able to reuse the crank if you plan on an overhaul.

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cool_as_crap said:

What happened to yours, what did you do to fix it?
Was it bearing related at all? How many miles were on it?

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Christian Steffen said:

I should have been more specific.

It was the main bearings going out, never made any noises out of the ordinary right up to the day I tore it down, which was at about 185,000 miles. We bought it at 100k and used it almost exclusively for towing and from what I was told the previous owner used it for towing mostly. So it had been worked fairly hard for most of its life.

I was having the exact same symptoms that you are, once the engine was warm it would have ~25 psi while cruising and drop to zero at every stop.

I pulled the engine and did a full rebuild. Turned it into a stroker with all new components and tried to make it better where I could.

That being said, the crank would have been reusable so I am assuming yours is probably fine too. So you can likely get by with new bearings through the motor and rings, but if you're in it that far I'd highly recommend a cam swap at least, and possibly freshening up the heads.

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88GMCtruck said:

Damn, that doesn't sound like a good deal. Mine runs a solid 70 PSI just about all the time.

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dave_erald said:

Vortec and tbi trucks were bad for oil pump pickups plugging and oil pumps giving up, your top end could be plugged and not letting it drain down well either, but if its only most noticeable between cold and hot then yeah it maybe time for bearings.

If possible drain the oil and scope it and look at the pump pickup. Next hook a mechanical test gauge up and confirm pressures. Happy hunting

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leakers said:

I would have a good look at your oil, and filter. Six months ago you seafoamed the engine, but only drove it for 90 miles before you drained the oil . You used half a container of seafoam ...I suspect you may have loosened a lot of old sludge but did not get it all out when you drained the oil.... and now it is in the sump and is blocking the oil pickup.. do something NOW and you might just save the bottom end.
I would take the whole motor out rather than try to change bearings in place...by time you remove the front diff and attack it from underneath, you could be done and dusted on an engine stand and be on the way back together.

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cool_as_crap said:

I've stopped driving it completely hoping to try to save the bottom end, I'm just going to hope for the best.
I'd love to stroke and cam it, just depends if i have to have it rebuilt or not.
Depending on cost and what I can get away with and still pass CA strict ass smog.

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Christian Steffen said:

I don't think you'll have any issues passing smog as long as the right parts are selected, but I've never had to try passing smog test so I'm just guessing. My mileage got better with the stroker, so that's a plus.

It wasn't cheap though, the parts were all expensive. Plus machine shop time for having the heads reworked, block bored and cleaned all add up. And that was my brother and I doing all the actual engine building work. I'm not going to say that it was a cost effective build going down the stroker road, but I do like how it runs for what that's worth.

I'm not sure if you have a budget you'll be trying to follow, assuming it does go down the rebuild road, but if so reusing stock components will be the cheapest. A cam swap is a must in my opinion though.

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