Tractor Posted March 12, 2021 Report Share Posted March 12, 2021 Now that I have a garage I moved my 2008 CTS 3.6L into it to try to get it on the road again. It's sat for a couple years now so here's what I know right now. One day I parked it, next day I went to start it and the timing had jumped so I replaced the timing chains and put it back together, however upon trying it out the oil pressure was reading about 5-10 on the gauge and the chains were rattling so I'm pretty sure that the pressure is low. I will put a mechanical gauge on it soon to confirm that. Any ideas? I'm willing to entertain that I put it together wrong or something is plugging the oil system or the oil pump went bad which caused the chain issue in the first place. I haven't diagnosed this type of stuff for a while but it can sit while I figure it out. Quote Link to comment Share on other sites More sharing options...
Green Bastard Posted March 15, 2021 Report Share Posted March 15, 2021 10 psi at idle may be okay, I would look at the oil pressure specs for that car. Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted March 15, 2021 Report Share Posted March 15, 2021 10 psi at idle may be okay, I would look at the oil pressure specs for that car. 10 psi @ idle, 20 psi @ 2000rpm is the spec. Quote Link to comment Share on other sites More sharing options...
Tractor Posted March 15, 2021 Author Report Share Posted March 15, 2021 5-10 at cold start is way low. Goes to zero after a minute or two and chains rattling. Normal cold start is always been at least 50 and worm idle a little above 20. That's my observation and the same as about anyone on car specific forums that I've searched. Example https://www.cadillacforums.com/threads/oil-pressure.124909/#:~:text=Around%2027%20psi%20at%20idle,psi%20at%2060-65%20mph. Quote Link to comment Share on other sites More sharing options...
Tractor Posted March 27, 2021 Author Report Share Posted March 27, 2021 Ok so I changed the oil bypass valve and upon starting up I had 20lbs for about 30 seconds, no chain rattle, seemed good except pressure is a bit low for a cold start. I throttled up to 2-3k and oil pressure moved up past 50lbs. After the initial 30 seconds or so I'm down to 10lbs or below and chain rattling. If I carefully increase RPMs back to 2k it slowly builds pressure back up past 30-50lbs and no chain rattle. I'm thinking, oil isn't getting up from the pan so oil pump or plugged screen but I'm not familiar with the car so any ideas? Quote Link to comment Share on other sites More sharing options...
PsychoticGaming Posted April 3, 2021 Report Share Posted April 3, 2021 At least yours seems to be oil pressure related. Mine ended up destroying the back side of the engine (threw rockers, broken valve and broke a cam cap on the intake side). Took it apart to find a bad new tensioner, had a burr on it not letting the tensioner do its job unfortunately Did you end up replacing the oil pump all together? I found Melling or maybe it was Cloyes saying not to change the guide on the oil pump for the timing chain on the crank or not to unbolt it as it can cause the oil pump to un-seat/seal (their youtube vid mentions this). Quote Link to comment Share on other sites More sharing options...
Tractor Posted April 3, 2021 Author Report Share Posted April 3, 2021 I've had an extremely busy past two weeks so I haven't gotten back to it. I probably won't get to it next week either unless I do some work this weekend. Good tip on the pump seal, I'll look on youtube. Anyone know where to get the good diagrams and instructions? I had some when I did the chain a few years ago, but can't find them in my file server. Quote Link to comment Share on other sites More sharing options...
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