Need help- 05 Gmc Sierra 5.3 (heavy towing&sludge)

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Love the forum. Not sure why I'm so interested in reading about oil, but I read daily lol.

I have a 2005 GMC Sierra 4x4 with a 5.3 vortec. I have owned several of these trucks with this engine and never had an issue like this. Previous oil changes before this latest one were clean. No visible issues at all. I pull my 24' camper, 21' bass boat, and 16' lawn maint. trailer. I was running pennzoil semi syn. 5w-30 with ac delco filter. 5,000 mile oci. I changed the oil a couple of weeks ago and the filter was completely full of sludge. The oil was really thin and jet black. When I say chunks I mean like, I dug this stuff out of the filter with a screw driver... When I refilled I went with Supertech Full Syn. and an ac delco filter.

Any thoughts?? Suggestions??? Or is there anything to worry about??

I tow with the truck 90% of the time. I have a company truck that I drive daily so this is my truck that I play with on the weekends...
 
Your filter did its job by keeping the sludge and chunks out of the engine. I would not worry too much, but if you are getting those results then I would run your OCI at 4K miles on that supertech. A blend may be good for that long as well but its likely the engine is chewing the oil up due to the towing loads and heat. Pics of the filter?
 
There's a cause and there's consequences.

You are telling us the consequences, you need to explore/find out the cause.

Is your thermostat faulty? Did you buy this vehicle used with unknown service/maintenance history?

and the list goes on...

Q.
 
I do have pics! Can't figure out how to post em. I have a photobucket account. What tag line would I use to post them?
 
I did have one over heating issue during the oci but it was due to low coolant and truck ran just above normal temp for just a minute.. I shut it down immediately. I don't think it was enough to cause the issue?? Possibly??
 
Same thing happened to me on an 05 Chevy. Ended up being a cracked head. Apparently they had a problem for a few years including 05 with Castech heads cracking. Chevy mechanic called it a cracktech head. Get it checked out.
 
Originally Posted By: Quest
There's a cause and there's consequences.

You are telling us the consequences, you need to explore/find out the cause.

Is your thermostat faulty? Did you buy this vehicle used with unknown service/maintenance history?

and the list goes on...



Q.



My thoughts exactly. SynBlend 5w30 should not have had an issue with a 5k run, towing or not. I would personally go with something more like Rotella T5 10w30 for your application, but any good 5w30 Synthetic shouldn't have a problem towing in a 5.3.
 
Originally Posted By: Quest
There's a cause and there's consequences.

You are telling us the consequences, you need to explore/find out the cause.

Is your thermostat faulty? Did you buy this vehicle used with unknown service/maintenance history?

and the list goes on...

Q.



Agreed.

A UOA will help to point you in the direction of the cause. This engine shouldn't have sludged up under that usage.

Could be from coolant intrusion from a head gasket or a faulty head (this engine was noted for that- certain castings) and/or excess fuel. Either way, a UOA would conofirm either of those.
 
Originally Posted By: Alex38
Originally Posted By: Quest
There's a cause and there's consequences.

You are telling us the consequences, you need to explore/find out the cause.

Is your thermostat faulty? Did you buy this vehicle used with unknown service/maintenance history?

and the list goes on...



Q.



My thoughts exactly. SynBlend 5w30 should not have had an issue with a 5k run, towing or not. I would personally go with something more like Rotella T5 10w30 for your application, but any good 5w30 Synthetic shouldn't have a problem towing in a 5.3.



Fixed it for you...
 
Something went wrong with the engine during this last run of oil.

You need to figure out what happened and resolve it.
 
Originally Posted By: 4Scott4

Any thoughts?? Suggestions???...I tow with the truck 90% of the time.


Amsoil ASL 5W-30: http://www.amsoil.com/shop/by-product/mo.../?code=ASLQT-EA

Amsoil Ea15K32 Filter: http://www.amsoil.com/shop/by-product/fi...code=EA15K32-EA

And given your frequent towing, upgrade your transmission fluid (and change your tranny filter while you are at it): http://www.amsoil.com/shop/by-product/tr.../?code=ATLQT-EA

But I do agree a UOA would help to diagnose if you have a core issue beyond any brand/OCI/viscosity issues that needs to be addressed first.
 
Why was the coolant low? The coolant should never be low unless there is a leak...


This is not an oil problem, that's not severe service for that motor and you could follow the OLM way past 5k and the motor would run forever.
 
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