01SikVette

I have a 98 Vette with a built 402 and twin turbos (PTK). After changing out the oil pressure sending unit, oil pump, and even going to a heavier oil, I still only get 9psi at warm idle? The oil pressure is fine when driving.

I changed my oil recently and there was no signs of bearing failure at all. I did do a mechanical oil pressure test off the turbo feed line and it came up low. Does anyone have an idea of what it might be? Would it be wise to do another oil pressure test but in a different location?

Eric D

Have you replaced the oil filter?

Any ticking noise or does the engine sound normal?

01SikVette

I put in a NAPA Wix oil filter and 15 40 oil. I do get some light ticking (sounds like a sewing machine).

Rob's 73

What are your bearing clearances? Which pump did you go with. The GM High Volume pump flows approximately 30% more.

Switch to 15w-50 oil

lucky131969

What's the history here? Is this a fresh build? Brand new problem, etc?

Chevy Guy

The bearings clearances are what determine pressure in the oil system. After replacing all the the common items, Id say you may have some wear somewhere. I could be anything from cam bearings to crank bearings. Did the pressure drop all of a sudden?

Also, did you check pressure with a mechanical gauge? You could use the front port for a real quick check.

01SikVette

I bought the car the way it is. The build has about 10k miles on it. I'm not really sure the history on the car but I do have all the receipts for the car and everything that was done to it. The motor was built by Scogging Dickey (strocked LS2).

I'm not exactly sure the bearing clearences but I would image the car was fine when first built.

01SikVette

I have the Melling high volume. I just changed the pump the today and still have the same oil pressure as before.

easyvette

Couple things to check.

The usual and the biggie is the o-ring on the oil pump to make sure it did not get pinched in anyway.

And make sure the pickup tube/screen in the bottom of the oil pan is clearanced enough. And the screen is clean around the pickup inside.

If you going to check the oil pump oring again. Might as well pull the cam and scope the cam bearings to make sure one has not slid. And make sure the cam retaining plate is tight.

I ran my car with the front cover off for a couple seconds before when I was having a problem to make sure it was not coming from the cam retaining plate and to make sure oil was not coming out around the o-ring.... Not to much of a mess.

lucky131969

To be clear. You bought the car as is, with a 9 psi idle oil pressure problem, or this just started recently?

Soul TKR

I was wondering what the update was on this John... figured you would have had this figured out by now

keep me updated...

01SikVette

I bought the car knowing it had low oil pressure. I was really hoping is was just the o-ring or pump.
Will do bro.

I was very careful installing the o-ring and pump so I'm pretty sure that's not it. I might just pull the oil pan and inspect the screen.

lucky131969

Ok, so you have no idea what you are chasing here...which sucks. Did the original owner say the oil pressure was always low, or is that the reason he sold the car? If it was that way from day one..who knows...maybe bearing clearances...oil galley plug, etc.

01SikVette

I bought the car off the guy who purchased it from the original owner. The car was sold because the current owner didn't know what was wrong with it. I purchased the car because I got it for a really good price due to the issue it's having. I've talked to the original owner once and he said it didn't have that problem when he owned it.

The car was in storage for six months before it was sold to the second owner. The new owner only put 200 miles on the car before selling it to me.

lucky131969

Thanks for the explanation. For future, it's a good idea to give full disclosure in your first post, so everyone doesn't throw the obvious fixes at you (which it seems you've already attempted anyway). Unless you get some super words of wisdom, something tells me you'll be tearing into the motor. Good luck.

01SikVette

I'm going to run another oil pressure test tomorrow, this time I'm going to run it off the block and plug the turbo feedlines.

1320IN9

i would try a mechanical gauge, maybe something wrong with the factory digital/analog gauge. 9psi sounds like the engine would have blown up by now or atleast rod knock or something. take the oil filter off put a pan under it and let it rip, watch to see how fast it's coming out and check for something blocking the filter area. twin turbo oil lines cloged or maybe forigen debris from the turbos blocking an oil passage somewhere

lucky131969

Not even....that motor will run with 9psi all day long..provided it's not push hard.

Great troubleshooting technique for an engine with a low idle oil pressure issue...take the filter off, and start her up.....so the oil pressure drops to zero...

BLOWNBLUEZ06

Sounds like an internal oil leak to me. By chance did you check the oil galley plug on the driver side front of the engine when you changed the oil pump? When you get the engine apart, check the dumbell in the back and the cam plate and pressure check the oil pickup tube to make sure it hasn't been compromised in any way. You may also want to create an external pump and make a block off plate for the existing oil pump and try pumping oil into the side of the block with the engine apart and see if you can identify the internal oil leak. I'm sure you'll find it before you have to take it that far though.

01SikVette

I did not check the galley plug. I assumed it was going to be the oil pump or o-ring. I'm really hoping that the oil pressure is fine and that I'm getting a false reading on the instrumental panel.

The oil pressure is fine under throttle. I'm only seeing low oil pressure at warm idle. I had the car on the highway the other day and I was getting 30psi cruising at 70 in 5th.