low oil pressure in new engine
 

ok the old engine I had the oil pressure sensore replaced the low oil pressure message came up and the save mode of the engine loss of power till the engine was turned off. for every five feet. yes I admit I am a bad speller please don't worry. when I had the engine out and sent it to a machine shop they said they couldn't find any thing wrong with the engine when they rebuilt it. well the 3.5 failed the first engine failed do to a piston going out the side before leaving the parking lot of the dealer. the second engine I had that recall for the head gaskets done with a pair of new heads. do to what the dealer said they were warped beyond repair. this is what I am thinking why gm stopped making the 3.5 v6 do to weird quarks of failure. when I took my old engine to the machine shop they said that it would be more money to get it right. 4 thousand. I said why they said how out of line the pistons were do to the main berring failure as well as the berrings for the pistons. so I got a new long block had them build it up to be new or better than what the engine was. now it is doing the same acting like there is no oil pressure. there is no knock or any thing I am frustrated. because the engine will go to limp mode every time it goes over 1k rpm in first gear. I am frustrated yes it tempted to put a whole new engine in it a 5.3 kind of tempting on putting a 3.8 in it. but I am at a loss.

Step 1 seems pretty simple; if you've got a low oil pressure light, you need to find out what the oil pressure actually is. Remove the sender and install a gauge, and compare that to the spec for this engine.

If the readings are good, the issue is clearly electrical (bad sender, wiring, pcm, etc). If the readings are truly bad on a gauge, the engine probably needs to come out to see what the issue is (machining issue, oil pump issue, clogged pickup, etc).


The stakes are pretty serious (ie the engine may be toast), so it may be best to take it to a reputable mechanic for analysis.

With all of the history you have listed for issues with this car, it's well past time to dump it financially. Obviously if it's not running, you won't get much more than scrap value- so I think it's worth a proper diagnosis. If it really does need a new engine, I really think the only viable options are to sell the car as non running, or pick up a used junkyard short block to get it up and running to sell it. I think it really comes down to if you can do the labor yourself or not.

Sometimes it's better just to cut your losses and move on, especially for the kind of repair money you've got in this one.

I did what you mentioned bumpin it was bouncing every where. what I mean it was bouncing from 35 psi to 90 psi. when it was at idle. the original engine didn't give a sign of failure till I started it from a cold start at work and hearing a really big pop. the piston went out the side. at the time it was under the extended warrenty the dealer replaced it. they said it was a number of reasons why it failed from bad bottom end parts. don't get me wrong kind of wish gm had this engine out just as long as the 3.8 but they didn't only 3-5 years before the 3.6 came out. the shop I took it to said they can put another engine in it. but they said they have been getting bad engine and parts for the type of engine. there looking into another manufacturer for replacement parts and engines. they said they will get in contact with jasper engines to see how and the quality of the 3.5 v6 if they will rebuild them or to see if I need to put in a different engine. all together like the 3.8 or the 5.3but they said it would be up to me. don't get me wrong I would like to have the 3.8 engine in it. to keep it a v6. but if reman type of engine is bad as well as new for the 3.5 I love the body and the ride. I might see if I can put in the 3.6 powertrain. I don't know if I need the bcm with the pcm and the tcm to get it running. I know I need the cradle for it because of the different mounting points of the engine

That is odd that it's bouncing all over the place like that. I wouldn't think a bad engine build would cause that. The low end numbers sound just fine, but 90 psi is way too much at idle.

I have no idea how the oil pump/bypass works on the 60 degree engines, but I would take a look at that first. Sounds like the bypass/regulator could be getting stuck closed and then suddenly pops open when pressure gets way up there.

I'm just thinking if something weren't assembled properly in the rest of the engine, you'd have permanently low pressure.

I dunno if I'd waste my time buying another rebuild if the last one sucked so bad. I'd probably see what local junkyards had. Would rather have something gm built than what some random rebuild shop cobbled together - especially on a stock engine.

The bouncing all over could be the gauge.Try a liquid filled gauge it dampens the pulses. I do agree with Bumpin96monte that getting out of this car is the best choice financially. The rebuilt should be brought to your rebuilder to straighten it out.I would expect that it comes with a warrantee. good luck with it.

got the engine rebuilt the failure point of it was the spot where the oil pump connects to. the looked all over the engine to see what was the failure the first time they smoothed every thing to help the engine. it left me a little ticked to be honest

So they had to rebuild the entire engine to fix the oil pump issue? Did it spin some bearings or something?

Thats part of the reason why I always suggest getting a used oem bottom end out of a junkyard. Too many hack jobs out there, and its such a labor intensive swap with so much money wrapped up in it to risk it.

it ended up spinning all of the bearings from the cam and bottom. jasper said they fixed the issue and it was covered. they said after a small amount coming back from people who put little miles on there cars from other shops. it threw a red flag at them to take a better look. it was that oil passage where the oil pump hooks to. little further up it it needed to be smoothed out and other passages to do the same. at least I got a warranty with the new engine if there is another issue with it. Ironically yes it is my dd but I don't go past 4k rpm ever with that engine. 35k max if that if I am passing some body. to be honest when I had to replace the transmission I paid a little extra for the 4t65ehd model and it seemed like the combo is more efficient than the non hd. I don't know why. but I very rare push it other than passing some body to get out of the way of some one else. jasper did say it is very rare on some thing like that gets passed them and they will do every thing they can to fix the issue.

I found why you've been having so many engine problems! These engines weren't meant to go over 30k rpm! Lol. Just messing with you!

I know what you mean. I never pass that mark or even get there if I did.