TomTom4049

I have a 1997 stock LT1. With last February's 23 degree nights and the fact that a local Chevy dealer put no antifreeze in it when they changed the water pump, I started it one morning and was greeted by billowing clouds of steam from the exhaust. Easy to tell from smoke, steam dissipates quickly while smoke hangs in the air a long time. This was from a bad head gasket. Too cold for me to work on it I added a bottle of stop leak/head gasket fix and that got me through last Winter. I continued to drive the car twice a week to work without incident. Late Fall came and I replaced the head gaskets. Coolant had leaked into cylinder # 7 (which I understand is quite common). New plugs, new roller lifters, new push rods, new rocker arms. New intake side gaskets and used The Right Stuff on the front and back of the intake.

While the heads were off I had them pressure tested (they were fine) and had them milled just a bit. Upon starting it after re-assembly I'm getting oil burning from the exhaust which it never did before. At 5K mile full synthetic oil change intervals it used not a drop of oil despite 151K miles on the clock. Tailpipes were always clean.

The heads were off for 2 months (Nov & Dec) and some rain water did get into a few cylinders. I removed it of course and started covering the engine.

That's the full history on it. Any ideas where the oil burning might be coming from?
Blueish in color its oil for sure but I'm totally stumped. Sticking rings maybe?

Chimera96

did you replace the valve stem seals and if so what kind/brand?

it is possible that when the motor sat and got rain in it one or more piston rings may have rusted to cyl wall and now don't seal as well

during the time coolant did "leak" into cyl 7 when you were still driving it certainly did not help things. bearings also take a hit when coolant/oil mix

a compression and leak down test will show what cyl/valves are low...then go from there

TomTom4049

Actually I'm not sure what brand seals they used.

Checking it again today it does still appear to burn some oil but far less than it was. I took the driver's side air injection fitting off and started it. I was surprised to see water mist shooting up from the air tube on the exhaust manifold. Appears to be coming from one cylinder judging from it coming in pulses. I also noticed a misfire on cylinder 3 according to my code scanner (blinking Service Engine Soon light).

While I was still driving it previously it wasn't losing coolant by the way.

I'm wondering if it has a cracked head that was undetected?

Chimera96

if the shop used the white teflon valve stem seals...those tend to let more oil through than the Viton ones

you really need to do a compression and leak down test on each cyl and go from there.

Your cyl 3 misfire may be ignition or fuel injector issue and a different problem than the white smoke issue

TomTom4049

Thank you for helping. I've decided to throw in the towel and take it to a mechanic. Working outside in Winter and little daylight in the late evenings after work is very limiting. I many not have properly prepared the block, could be a cracked head or block. I sure didn't like the look of the FelPro head gaskets I used, the rings around each cylinder were uneven to say the least. A three year-old could draw a better shaped circle. Perhaps I expected more precision than that and my expectation is unrealistic.

I had gone over the block deck with WD-40 and green scotch brite followed by a razor blade on a handle scraper. I finally wiped the deck down 3 times with clean rags soaked with Brakekleen to remove any traces of oil (new clean rags each time). I was careful to chase the head bolt holes prior to wipe down and had used a shop vac with a long small hose to clean out each bolt hole, oil, & coolant ports. I used 3 old head bolts (long, med, & short) that I had cut with a angle grinder just like a tap has on them. They went all the way until they stopped.

It would be nice if it were not a bad head or block so I'm hoping it was not the best prep work I did. I replaced head gaskets twice before, on a '71 Grand Prix 400 and later on a '77 Seville's Oldsmobile 350 without issue. This LT1 has made me feel very inadequate. My first go-round with a Chevy engine and $800 in parts ends in defeat.

Chimera96

The block prep you did for the head swap sounds fine. I think we have all been there with a car, frustrating.

The shop will likely do a leak down and compression test. Not something you want to be doing outside in freezing temps.

FWIW I have never had any problems with FelPro, or GM, head gaskets.