I just put a new timing cover and oil pump (stock replacement gears with TA booster and adj regulator) in my 350. Motor has only 2500km on it. Oil pressure is great at all rpm but only makes about 12psi at idle. Shouldn't it be higher than this? What would cause this to happen?
I agree, 12lbs at idle is fine. Anything less than 10 at a normal idle would be cause for concern. Dan
Thats why the pump and timing cover were redone, idle pressure was only 10psi, i took it apart and found the timing cover was badly worn. But dont you think the new cover and pump with booster plate would give me better than 12 at idle, thats only 2psi more than before. What oil are you guys using?
Wow..... I get the "heebie-Jeebies" when I see that low of pressure. I am used to running 20w50 Valvoline Racing oil though. Since I never run the car when its colder than 60* it is not a pronlem with being too thick either. I usually see 20lbs at idle when its real hot.....25 normal when its 70-80* out, and 50-60lbs at 4500rpm You might try 10w40 ......
20w50? Isnt that kinda heavy? I remember talking to Kenne Bell and they recomended pennzoil 5w30. Im running 10w30 also.
I just switched to Mobil 1 20-50 and am very happy with it! A cheaper alternative would be to go with Penzoil 20-50 or SAE 30w. Penzoil is good stuff.
oil yea i use 10w30 but the previous owner said to use 20w50. i switched it to 10w30 becuase i thought it was heavy to but u know i live in canada and it doesnt get to to warm here so.u know, maybe i shoulda stuck with the 25w50
5w30 ..... maybe in a race engine that has some pretty close tolerances. I always ran 10w40 in the "stock" wheels that I had over the years and if I did any modifications, I used 20w50...... always used Valvoline. 5w30 is just way to thin unless you and your machine shop have been doing alot of work. On the newer cars......ya 10w30 is great ..... and I would use nothing heavier than that. Just don't dump 20w50 in and plan to start her up on a 30 degree morning though. :shock:
oil pressure i use 10w40 castrol gtx in my gs 350 & at idle , the oil pressure is about 13-14 lbs . if i had an older v12 jag, then i would have to run 20w50 , but i donot see the point in a 50 grade oil in the 350 . is 20w50 listed in the owners manual or shop manual as a viable oil grade ? i do not remember seeing it , although i could have missed the item . gerry
Regal350 I hate to rain on every ones parade here but I think you may not be getting the best advice. On my 350 I have used 10W30 and 20W50 conventional oil in the past. I'm using a 15w30 synthetic now. 12 lbs is to low for what you have done to the oil pump and indicates that you have to much bypass in the pump or you are loosing oil pressure due to clearance issues some where either in the pump itself or around the bearings. What type of oil pressure gauge are you using? Are you totally sure that it is accurate? With 10W30 I get a good 30 to 35lbs of pressure when the engine is cold and it never drops below 25 when it's warm. Now I have a newly rebuilt engine and the tolerances are all very tite. Before the rebuild I would see 10lbs at idle and it really isn't a concern unless you are idleing above 1000 rpm. 10 lbs per 1k rpm is good on a 350 but you never want to have your regulator set to give you more than 45 to 50 lbs no matter how high you spin the motor. A quick lesson on Oil. The W in motor oil ratings stands for Winter. Not Weight. The first number is for the base oil used and that is a weight. 10 weight, 20 weight and so on. The second numbers are Viscosity ratings that the oil will maintain in cold tempretures. The closer the first number is to the last the better the oil is for protection qualities. Never use a 10W40! Evan GM has recognized the danger of using this motor oil and stopped recomending it. As a matter of fact they wont honor engine warenties when an engine has failed if 10W40 is being used in it. 5W30 should never be used in an engine that is not brand spanking new and designed for that grade of oil. Your 30+ year old engine was never designed to use that light of an oil and you will end up with excessive wear to your engine if you use it. 30W oil is great if your engine already has a lot of miles and more clearance in it than it should. Or if you plan on racing and the temps are 90 deg. or hotter in the summer. Oh yeah, you also shouldn't use it if the temp. outside drops below 55. Any colder temps will cause the oil to congel and give poor flow qualities and excessive wear on the motor while the engine is trying to warm up. Stick with 10W30 for the winter and try the 20W50 for the summer. If you don't see any change in pressure when you change to the 20W50 go back to the 10W30 until the engine starts to use oil. 20W50 can help to cut down on oil consumption in a higher mile engine.
oils in the 25+ & older engines, i agree that 5w oil too low a viscosity to run in these engines . there is nothing wrong in using a 10w40 oil year round in a 350 . i used to work for an oil company 30 years ago . drag racing these engines presents a whole nother scenario ! . i live in ontario canada and would never use a 20w50 oil . the newer engines actually recommend 5w30 & 10w30 oils - 99 saturn 5w30 , 98 regal gs 10w30 . i would use synthetic oil in a new car, but never in an old engine unless that engine had been completely rebuilt . synthetic oil will discover every marginal gasket/seal and they will leak . that my opinion gerry
Like I said my motor has only 2500km on it so low pressure shouldnt be caused by excessive bearing clearance. So your saying even with the lighter oil I should have better than 10-12psi at idle hot? If I check clearances within the pump and they're good should I be assuming I have internal bearing clearances that are higher than they should be on such a fresh engine? Any signs to look for to detect this other than tearing it apart? It doesnt burn oil.
With a new cover, oil pump gears, and thrust plate you really should be seeing around 20 lbs or higher. I would recheck the pump and see if any thing is amis there. Honostly there are to many factors to determine what might be causing oil pressure loss. I would look inside the drivers side oil filler hole and see if you get plenty of oil slinging around in there when you rev the engine a little. If you do, than your probably getting oil every where you need it in the engine. I can only say if it's a big concern for you try to find a friend with good knowledge to help you diagnose what may be causing the porblem. One last thing, you didn't mention if you fully trust the oil pressure gauge you are using. I would check this before ever thinking of going into the engine again.
The gauge is brand new, its a sunpro mechanical. I changed the oil (10w30) and filter. I guess there was a restriction in the filter from the vasoline used to pack the pump gears. I am now getting 15-20psi at idle hot. I know it could be better. Like I said the timing cover is an aftermarket replacement which may not have as exact clearances as a GM piece. I am going to pull off the pump cover to double check the end and side clearances to see if this is the cause. If the clearances are a little off would it be a good idea to run a hi vol/ hi press pump and loosen off the pressure regulator to prevent excesive pressure? Thanks
Hey Regal whats your name? I would not run a hi pressure pump there is no need to do that and you will wear out parts in your engine faster. 15-20 when it's hot sounds good. I wouldn't worry about it any more. You can pull the cover and recheck the clearances if you feel you really need to but I think you are right where you need to be. stick with the 10W30 and change it regularly. I'm glad to hear that it was some thing simple that only cost you a little to fix.
Thanks Jason. My name is Liam. I am also definately relieved that the problem is solved. Im guessing if I had ordered a GM cover the pressure would probably be a little better but it sounds like 15-20 is good. Now that I got that taken care of its time for a TA intake and some ported heads!
