GM LSx oil pump relief valves

[undertow]

I've been kicking around the idea of picking up an LS1-powered Commodore recently, but some googling indicates that the oil pump relief valves in the LS family engines are prone to sticking open (with predictable results). It appears to be more common in cars that have had head and/or cam swaps, probably due to junk getting into the motor. But I've also read several cases of failures in stock cars; it seems to become more common after 100k miles or so.

My thinking is that failures in stock cars may be caused by long OCIs and varnish buildup, or bits of carbon deposits breaking off and lodging in the valve. I can't see why the relief valves would just hang up on their own after working for 100+k miles.

Any BITOGers experienced this in well-maintained cars?

 

[default]

I've seen what was presumably a relief failure on a 5.3 tuck engine that stuck, shut when put in neutral and revved, and them stuck again blowing the internals to bits and locking up that time. I didn't get to tear that one down (just bought and the dealer ate it). However, research on the topic seems to show they usually dont stick all the way open and you just get a low pressure condition that if taken care of doesn't hurt the engine. The LS is ridiculously strong.

 

[Chris142]

I have not seen any with this problem here

 

[dailydriver]

Mine has ~160K HARD miles on it now, and NO problems yet in this area, but I am at psychotic level OCD about top tier synthetic/premium grade filters OCIs, IF that meant anything at all??

But, just to head off the potential for problems at the pass, when I change my; balancer/damper, and water pump, I am going to go ahead and change out the whole oil pump with a ported/blue-printed/high performance one, as well as a new timing set.

 

[undertow]

Sounds like a good plan. Some say the timing chains are weak, but they seem to be ok for standard cars.

Looked at a car on the weekend that (apparently) had only 130,000 km but was heavily varnished/lightly sludged inside and had hard carbon under the oil cap, destroyed rear tires, AND was actually a year older than advertised. Dodgy

 

[SteveSRT8]

Originally Posted By: undertow
I've been kicking around the idea of picking up an LS1-powered Commodore recently, but some googling indicates that the oil pump relief valves in the LS family engines are prone to sticking open (with predictable results). It appears to be more common in cars that have had head and/or cam swaps, probably due to junk getting into the motor. But I've also read several cases of failures in stock cars; it seems to become more common after 100k miles or so.

My thinking is that failures in stock cars may be caused by long OCIs and varnish buildup, or bits of carbon deposits breaking off and lodging in the valve. I can't see why the relief valves would just hang up on their own after working for 100+k miles.

Any BITOGers experienced this in well-maintained cars?


With all the 5.3's and 6.0's around here we've only had this issue one time on an engine with over 200k miles. it spun the first main bearing and scuffed the crank a bit. Reground with oversize bearings for a cheap fix.

It DOES happen, but it is far more rare that Internet hooey would suggest.