This. Throw the synthetic oil recommendations out with the bath water. Synthetic oil does not repair broke.
Need help- 05 Gmc Sierra 5.3 (heavy towing&sludge)
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I agree with most people, something changed. The towing that you are doing is nothing. I had a 03 with same engine 5.3 I was towing right around 7500-8000lb car hauler and pulling a mountin 4 times a week. I worked the heck out of that truck. Did that for 6-8 mths before I purchased what i have now(1 in sig).
I ran m1 filter and m1 5w30. I changed when olm indecated so. I never had an issue with sludge.
I agree with coolent leak inside engine. If i remember the only place for that to happen is head gasket or cracked head/block.
Pull spark plugs an inspect, one that is wet/damp is the problem cylnder.
I ran m1 filter and m1 5w30. I changed when olm indecated so. I never had an issue with sludge.
I agree with coolent leak inside engine. If i remember the only place for that to happen is head gasket or cracked head/block.
Pull spark plugs an inspect, one that is wet/damp is the problem cylnder.
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Find out where the coolant is going. I'm not that familiar with GM's but I do know I serviced a few 5.3 Silverado/Sierra trade ins that had coolant in the oil. They got sent to the auction! From some of the other comments here it sounds like that's not too uncommon.
Originally Posted By: hattaresguy
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.
Bingo. Find out why your coolant is disappearing.
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.
Bingo. Find out why your coolant is disappearing.
Originally Posted By: Chris142
http://www.speedtalk.com/forum/viewtopic.php?t=19878
The page this references has a link at the bottom with great picture resources. I hope it isn't the Castech head problem, but it sounds like it might be. I would definitely check it out. The good news is that the problem is widespread enough that there are lots of resources on the repair. Just do a Google search. I hope this isn't your problem, but your truck fits the profile. Good luck.
http://www.speedtalk.com/forum/viewtopic.php?t=19878
The page this references has a link at the bottom with great picture resources. I hope it isn't the Castech head problem, but it sounds like it might be. I would definitely check it out. The good news is that the problem is widespread enough that there are lots of resources on the repair. Just do a Google search. I hope this isn't your problem, but your truck fits the profile. Good luck.
Originally Posted By: sopususer
Originally Posted By: Chris142
http://www.speedtalk.com/forum/viewtopic.php?t=19878
The page this references has a link at the bottom with great picture resources. I hope it isn't the Castech head problem, but it sounds like it might be. I would definitely check it out. The good news is that the problem is widespread enough that there are lots of resources on the repair. Just do a Google search. I hope this isn't your problem, but your truck fits the profile. Good luck.
Overheating during the OCI due to low coolant level. The OP's vehicle seems to fit the profile for this problem. Here's a case where a UOA would be money well spend, if it shows coolant in the oil I'd have a long hard look at the cylinder heads.
Originally Posted By: Chris142
http://www.speedtalk.com/forum/viewtopic.php?t=19878
The page this references has a link at the bottom with great picture resources. I hope it isn't the Castech head problem, but it sounds like it might be. I would definitely check it out. The good news is that the problem is widespread enough that there are lots of resources on the repair. Just do a Google search. I hope this isn't your problem, but your truck fits the profile. Good luck.
Overheating during the OCI due to low coolant level. The OP's vehicle seems to fit the profile for this problem. Here's a case where a UOA would be money well spend, if it shows coolant in the oil I'd have a long hard look at the cylinder heads.
Originally Posted By: 4Scott4
When I refilled I went with Supertech Full Syn. and an ac delco filter.
An ACDelco e-core or a classic?
I've used e-core filters in the past and haven't had a failure, but I've never used one where there was a possibility of becoming filled with sludge and having a possible blowout. If you used the classic, fine. Otherwise, in this case, there are better filters available than the e-core.
If you are loosing coolanat, I'm with others in finding the reason.
When I refilled I went with Supertech Full Syn. and an ac delco filter.
An ACDelco e-core or a classic?
I've used e-core filters in the past and haven't had a failure, but I've never used one where there was a possibility of becoming filled with sludge and having a possible blowout. If you used the classic, fine. Otherwise, in this case, there are better filters available than the e-core.
If you are loosing coolanat, I'm with others in finding the reason.
tip: Drain all the coolant, then do a pressure-test on cooling system dry(can rent pressure-tester free at Autozone). Small slow leak (especially head crack or gasket) will be more obvious when system is tested with air ; If it does leak (can't hold 15lb pressure for 2-3 hours) you can pull plugs, and listen into each spark-plug hole (using hose)- you can hear hissing if leaking into combustion chamber - you will know for sure if it's worth tearing heads off.
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