changed the oil today in a friends truck, 1998 1500 GMC Sierra. previous owner used Pennzoil Conventional 10w40, he wasnt really aware im assuming that it specs 5W30. truck had 179,358 miles when i changed it, 4 qts T6 5W40 and 1 qt Rotella 5W40, CI-4 spec, with a puro classic. Given the poor maintenance the previous owner gave it, (engine is in rough shape but runs fine) would the T6 hurt it? coldest it gets down here is about 30 degress. thinking of using Rotella T 10W30 next time.
5.7 Vortec T6
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How often was the previous owners OCI's?
I would stick with it. Great oil!!! With all those miles it won't hurt to go up a grade
no idea. had some hard cruddy build up on the oil cap, havent taken a look inside the fill hole, will do.
Originally Posted By: mobilaltima
no idea. had some hard cruddy build up on the oil cap, havent taken a look inside the fill hole, will do.
Then I would tread lightly and would not push the next 2-3 OCI's further than 5K also check the coolant overflow to see if the engine has a undiagnosed coolant leak.
no idea. had some hard cruddy build up on the oil cap, havent taken a look inside the fill hole, will do.
Then I would tread lightly and would not push the next 2-3 OCI's further than 5K also check the coolant overflow to see if the engine has a undiagnosed coolant leak.
Originally Posted By: dave1251
Originally Posted By: mobilaltima
no idea. had some hard cruddy build up on the oil cap, havent taken a look inside the fill hole, will do.
Then I would tread lightly and would not push the next 2-3 OCI's further than 5K also check the coolant overflow to see if the engine has a undiagnosed coolant leak.
You can pretty much bet the farm if the intake gaskets haven't been changed they are seeping
Originally Posted By: mobilaltima
no idea. had some hard cruddy build up on the oil cap, havent taken a look inside the fill hole, will do.
Then I would tread lightly and would not push the next 2-3 OCI's further than 5K also check the coolant overflow to see if the engine has a undiagnosed coolant leak.
You can pretty much bet the farm if the intake gaskets haven't been changed they are seeping
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
5.7 Vortecs have coolant in the manifolds and the are very prone to leaking into the crank case.
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
we have a 2000 chevy 3500 with the 454 vortec engine at work as our service truck and had to put a crate motor in it at around 35,000miles because management continued to ignore the coolant leak at the intake manifold we kept telling them about. One of our guys "punched it"to merge onto the highway one day and it spun all of the main bearings due to coolant contamination. I know cause I'm the one that got to disassemble the engine. Its a shame cause the truck was still under warranty when we first noticed the coolant leak. Its definately worth checking out before its to late.
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Originally Posted By: afoulk
we have a 2000 chevy 3500 with the 454 vortec engine at work as our service truck and had to put a crate motor in it at around 35,000miles because management continued to ignore the coolant leak at the intake manifold we kept telling them about. One of our guys "punched it"to merge onto the highway one day and it spun all of the main bearings due to coolant contamination. I know cause I'm the one that got to disassemble the engine. Its a shame cause the truck was still under warranty when we first noticed the coolant leak. Its definately worth checking out before its to late.
The bigblocks do it too. You learn something new everyday! !!
we have a 2000 chevy 3500 with the 454 vortec engine at work as our service truck and had to put a crate motor in it at around 35,000miles because management continued to ignore the coolant leak at the intake manifold we kept telling them about. One of our guys "punched it"to merge onto the highway one day and it spun all of the main bearings due to coolant contamination. I know cause I'm the one that got to disassemble the engine. Its a shame cause the truck was still under warranty when we first noticed the coolant leak. Its definately worth checking out before its to late.
The bigblocks do it too. You learn something new everyday! !!
I run t-6 5w40 in my 93 Silverado with a 305.
It gets well below zero where I live and it starts easily.
Its slowly cleaning some of the crud from the previous owners neglect.
In my experience T-6 is a great oil for a small block chevy!
It gets well below zero where I live and it starts easily.
Its slowly cleaning some of the crud from the previous owners neglect.
In my experience T-6 is a great oil for a small block chevy!
Originally Posted By: electrolover
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
Interesting - my dad's 1997 truck started leaking at 138K....
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
Interesting - my dad's 1997 truck started leaking at 138K....
Originally Posted By: electrolover
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
So these truck engines are neither LT1 based (as used in C4 vettes/4th gen f bodies), or LSx based, but an older small block design??
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
So these truck engines are neither LT1 based (as used in C4 vettes/4th gen f bodies), or LSx based, but an older small block design??
Yep. The distributor is in the back, like the earlier small block chevys, as opposed to the opti spark up front like the LT1.
My '97 Vortec 5.7 started leaking at 66000 miles. I replaced the intake manifold gaskets with factory (no clue if they were improved) before I knew about the Dexcool/gasket incompatibility. I now run G-05 without a problem.
My '97 Vortec 5.7 started leaking at 66000 miles. I replaced the intake manifold gaskets with factory (no clue if they were improved) before I knew about the Dexcool/gasket incompatibility. I now run G-05 without a problem.
so would it be better off with T6 year round, or Rotella T 10W30?
Originally Posted By: mobilaltima
so would it be better off with T6 year round, or Rotella T 10W30?
T6 year round.
so would it be better off with T6 year round, or Rotella T 10W30?
T6 year round.
Originally Posted By: dailydriver
Originally Posted By: electrolover
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
So these truck engines are neither LT1 based (as used in C4 vettes/4th gen f bodies), or LSx based, but an older small block design??
Correct. Its a gen 1 sbc with a different intake manifold to match the revised runners. Cast iron vortec heads flow 220 cfm stock which makes them a great upgrade for oldschool sbcs. But you have to run 10 deg less total timing because of the fast burn chamber design. And they always crack inbetween the combustion chambers starting at the center head bolt hole.
The vortec 305s had the same problems as well
Originally Posted By: electrolover
Originally Posted By: dailydriver
^^^^ I don't believe that either the 5.7 Vortecs, nor the LT1s had coolant running through the intake manifolds (unless you meant seeping air/vacuum??)
The cast iron vortecs....the real vortec, not the ls1 with a vortec badge, 96-98 all leak coolant from the intake gaskets at around 130k. The 4.3 vortec is the same way.
So these truck engines are neither LT1 based (as used in C4 vettes/4th gen f bodies), or LSx based, but an older small block design??
Correct. Its a gen 1 sbc with a different intake manifold to match the revised runners. Cast iron vortec heads flow 220 cfm stock which makes them a great upgrade for oldschool sbcs. But you have to run 10 deg less total timing because of the fast burn chamber design. And they always crack inbetween the combustion chambers starting at the center head bolt hole.
The vortec 305s had the same problems as well
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