5.7 vortec smokes like a diesel at start

[demetrio bazan]

Or a spider or FPR that leaks down when you shut the motor off.

The fpr was replaced about 6 months

 

[demetrio bazan]

Or a spider or FPR that leaks down when you shut the motor off.

Spider was replaced unnecessary a couple of years ago

 

[jkeaton]

Engine was replaced when? Better start now....

 

[demetrio bazan]

Engine was replaced when? Better start now....

The spider unit was replaced
It still has the original engine

 

[Coveman]

color of smoke tells you something:
black-too much fuel
white- too much air
blue- burning oil

worn rings burn oil constantly, blue smoke on start up is most likely oil dripping down valve seals into combustion chamber

a compression test will tell you how things are holding up, and whether some cylinders are farther along than others

at 300k i’d say 20w50 or straight 30w until you swap engines, she must be a runner

 

[DerekTheGreat]

At full operating temperature, straight 30 weight oil will be the same viscosity as 0/5/10w-30, so of the two, 20w-50 is "thicker."

For clarification:
The "w" stands for winter and in general, the lower the number, the better the oil will flow at lower temperatures. So a 0w-30 will be less viscous than a 10w-30 of the same brand at the same low temperature. I believe the "low" temperature as described in the ASE test method for cold viscosity is 32F. Lastly, "0 or 5 or 10"w does not mean the oil is a 0, 5 or 10 weight oil at 32F, rather, it means it BEHAVES as a 0, 5 or 10 weight oil would when at that temperature. This is why the lower number offers better protection during cold start-ups as it'll flow better when cold. However, make no mistake that all oils will still be very viscous when cold.
Here's a fun link to read up on that stuff in anyone is interested:
https://www.valvoline.com/about-us/faq/oil-types-weights-and-viscosity-faq

I sure as hell would not want to find out how straight 30 oil flows in my crankcase at 32F (or less, yikes) no matter how worn out my engine is. Before I studied up on multi viscosity oils I once thought it was OK to run 10w-40 conventional in an old I6 powered Ford truck. Well, I went to start that thing when it was -4 or -10 out and it took a solid 6 seconds before the oil pressure gauge read anything and lifters began to clatter around 2 seconds. Poor cylinder walls and main bearings...

 

[Mike Duckworth]

Normally if it is leaking oil through the valve guides it will blow blue smoke out of the tail pipe when you first crank it up and after it sets parked for several hours and you crank it again. You can pull the spark plugs and you will have oil build up on the side of the porcelain part of the plug that points up towards the valves. The oil drips down through the guide when the motor is off and the valve is open. I went through this before. Just my 2 cents worth.

 

[demetrio bazan]

Normally if it is leaking oil through the valve guides it will blow blue smoke out of the tail pipe when you first crank it up and after it sets parked for several hours and you crank it again. You can pull the spark plugs and you will have oil build up on the side of the porcelain part of the plug that points up towards the valves. The oil drips down through the guide when the motor is off and the valve is open. I went through this before. Just my 2 cents worth.

Ok I'll try that

 

[demetrio bazan]

color of smoke tells you something:
black-too much fuel
white- too much air
blue- burning oil

worn rings burn oil constantly, blue smoke on start up is most likely oil dripping down valve seals into combustion chamber

a compression test will tell you how things are holding up, and whether some cylinders are farther along than others

at 300k i’d say 20w50 or straight 30w until you swap engines, she must be a runner

Ok

 

[JackE]

A few years ago I fixed a "shot" K5 with your symptoms. The guy brought it in to have us replace the worn out engine. It smoked like a chimney on every startup within about 15 minutes of shut off. Immediate shut off and restart there was no problem. I took off the valve covers and used a screw driver to clean out the drain back holes in the lowest point of the heads. They were all gummed up and wouldn't let oil drain out of the heads, so it would seep in through the valve seals. 30 minutes and some new valve cover gaskets and he was a very happy customer. Probably not your problem if you keep good maintenance on it, but worth checking out.