The GM 3.5 DOHC is a fun and powerful engine and was used in almost every GM platform.
Oil in the spark plug tubes does indicate you need new valve cover gaskets. They likely have gotten hard and brittle.
The biggest issue with this engine is the timing chains. They stretch over time and the cam phasers cannot keep the cams in phase. Usually 100k miles and you will get a code for camshaft timing failure. Extended oil change intervals will cause the chains to wear out faster.
If you have an engine code for cam timing you will need to replace the timing chains, hydraulic tensioner sand guides.
If you have a shop do it, it is a big job, probably $1k+.
If you ever do the timing chain, the valve covers need to be removed so the v/c gaskets will be replaced as part of that job, just an FYI.
For your second question with the traction control light; the traction control off light will come on any time there is an engine code. The ecm disables traction control when an engine fault is active.
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Oil in the spark plug tubes does indicate you need new valve cover gaskets. They likely have gotten hard and brittle.
The biggest issue with this engine is the timing chains. They stretch over time and the cam phasers cannot keep the cams in phase. Usually 100k miles and you will get a code for camshaft timing failure. Extended oil change intervals will cause the chains to wear out faster.
If you have an engine code for cam timing you will need to replace the timing chains, hydraulic tensioner sand guides.
If you have a shop do it, it is a big job, probably $1k+.
If you ever do the timing chain, the valve covers need to be removed so the v/c gaskets will be replaced as part of that job, just an FYI.
For your second question with the traction control light; the traction control off light will come on any time there is an engine code. The ecm disables traction control when an engine fault is active.
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