2004 Chevy 5.3 L

[bwolford]

Hi all,

 

I was wondering if I could get some help from you guys. I have a 2004 Chevrolet Silverado with a 5.3L V8 with 109k on it. I bout this truck back in October of 2011 with 96k on it and everything ran great. The seller had stated to me that he had only used Mobile 1 Synthetic for oil changes since day one and he was the only owner of this vehicle. When it came to me changing the oil for the first time I went out and bought the same oil as he had stated. With in 300 miles after changing the oil the engine began to knock extremely loud on start ups. I could not figure out waht was going on and took it to a mechanic shop down the street from me and he took a look at it. He said that the seller must have not really used a synthetic oil which made the lifters tap as loud as they did. He changed my oil over to a conventional oil and the truck seemed to be working fine after that. About 500 miles after that the knocking came back. I began to lose oil and I was losing anitfreeze. I continued to drive the truck and the knocking was only on start up and was at random. I have an hour drive to work and when parking the truck in the parking lot for a couple hours i would see a puff of blue smoke (oil) on start up from the vehicle. There are no clear leaks of antifreeze or oil under the vehicle or in the engine bay. I have asked many people what they think is going on and they all say that it is a head gasket leak or an intake gasket leak. The oil is not contaminated with antifreeze so i do not see where that could be an issue. I changed the spark plugs the other day and there was no sign of oil build up or water on the tips. The vehicle has now gotten to the point that it sputters at idle after driving for a couple of minutes. I was cleaning the throttle body the other day and look back in the intake and saw a pool of oil. This was unused oil like i had just poured it out of the bottle. People have told me that the only way that the oil could have gotten there is from the PCV valve. Unlucky for me that is made into the valve cover.

 

I am to the point that i might listen to other on just getting a used engine and putting that in the truck. The only thing is that i need to figure out what is wrong with this current engine. The will run great at times and then sputter out of no where at idle. Could this PCV vaulve cause this or am i looking at a bigger problem here.

 

Please help me in figuring out the problem. I have ran around in circles on this thing to the point that i would rather have a rod sticking out of the side of the block then to just replace a motor that runs fine at times with no real sign of whats going on.

 

Thanks for the help. And sorry for writing a book on this, as you can see i have been through a lot with this truck in the last 6 months of owning it!

[jaredlucky16]

The puff of smoke of start up is most likely due to bad valve seals. As for loosing coolant look under the water pump and check for leaks. As for the loud tapping I think about all chevy trucks make that noise.

[Jsdirt]

My '07 puffs a bit at start up too ... and has since it hit about 15K miles. Has 52K on it now. Guess this is "normal" these days ...

 

But anyway ... my first thought after reading your post, bwolford, was that the seller tossed in some 20W-50 ... or maybe even gear oil, in order to quiet the machine down for the buyer. When you put the correct weight oil back in, she started clattering away.

 

Just an assumption - you never know. I live in a state where 90% of the population has no morals, so that kind of crafty behavior is par for the course here.

[rdnkcpa]

If you are losing coolant with no leaks: 1st check the water pump, next, do a search on Castech head problems. I have a 2004 and ended up replacing the heads in my truck. If the previous owner of your truck let the head problems go to long, the coolant will leak down into the crankcase and destroy the lower end.

 

Good luck.

[bwolford]

If you are losing coolant with no leaks: 1st check the water pump, next, do a search on Castech head problems. I have a 2004 and ended up replacing the heads in my truck. If the previous owner of your truck let the head problems go to long, the coolant will leak down into the crankcase and destroy the lower end.

 

Good luck.

 

My '07 puffs a bit at start up too ... and has since it hit about 15K miles. Has 52K on it now. Guess this is "normal" these days ...

 

But anyway ... my first thought after reading your post, bwolford, was that the seller tossed in some 20W-50 ... or maybe even gear oil, in order to quiet the machine down for the buyer. When you put the correct weight oil back in, she started clattering away.

 

Just an assumption - you never know. I live in a state where 90% of the population has no morals, so that kind of crafty behavior is par for the course here.

 

The puff of smoke of start up is most likely due to bad valve seals. As for loosing coolant look under the water pump and check for leaks. As for the loud tapping I think about all chevy trucks make that noise.

 

I appreciate your feedback with everything. With these examples I still do not have much to go off of. I think this may come to the point that I should get another engine and hope for the best. I do not understand why the engine is now sputtering. There must be a explanation for this and seems to be more problems than just one. With the amount of money i would pay in labor I might as well put in another motor. correct?