Excusetobooost

Hey guys i recently got my new gsr css block running and i noticed an issue with my oil pressure. Ive been researching before i take the engine apart. Oil pressure is in the 30s at cold idle then sits around 17psi at warm up.. after driving for a while it drops as low as 4 psi. If this matters i have a digital oil pressure guage from amazon. I have oil squirter block offs and a moroso oil pan ..stock gsr oil pump.. currently 5 quartz of 10w30 full synthetic. I have the oil sending unit in a T with the oil feed line. Oil pressure rises normally during driving. 4-5k rpm i see 55-60 psi. Any suggestions will help. Thank you.

DaX

iTrader: (1)

Do you know what your bearing clearances are? Larger clearances require thicker oil. I started out with 5w30 oil and was having similar low pressure issues at idle. I'm now using 10w30 and it's a little better, but on a hot day at idle I may see around 8 psi, and I've got my gauge set to show a warning below 10 psi. On the next oil change I may try some 15w40 or even 20w50 oil. Some people here are against sending unit style oil pressure gauges, but I am kind of doubting that's the problem for my car. I'm curious to hear what others are thinking.

Excusetobooost

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Im not sure what the bearing clearance is but the bearings were changed a second time by the machine shop because they were originally too tight. I have the number written down somewhere of the exact bearing clearance. I will try a thicker oil and see if that helps.. ive only driven the car 13 miles with this issue. Ill also put back the original oil pressure sensor.

DaX

iTrader: (1)

For comparison, I'm running a CSS D16Z6, and my clearances were 0.0015 - 0.0017 inch, if I recall correctly. I'm using an AutoMeter SpekPro oil pressure gauge with sending unit. I just changed to a new OEM oil pump, not ported or shimmed. I see as high as 80+ psi on the first startup in the morning, but after giving the car time to fully warm up, my cruising oil pressure is ~40 psi. With AC blasting at idle, most of the time it settles around 10-12 psi at idle (maybe 900-1,000 RPM), but sometimes the idle dips with all that electrical load and I'll see somewhere down around 8 psi.

Excusetobooost

Thanks, i see high 50s when its at cold idle. I attached a picture of the clearances maybe that will help trying to figure this out.

Txdragon

Thicker oil, bruh! .002, you should be running 15w40 at minimum..

DaX

iTrader: (1)

^Agreed. I'd try some 15w40 or maybe even 20w50.

Excusetobooost

Thanks guys. My local store has valvoline 20w50... The 15W40 says it is for diesel engines rotella

maxwellmercer

Rotella diesel 15W40 is perfectly fine to use.

TheShodan

iTrader: (14)

Mainly for E85. the valvoline should have a nice zinc content for that weight.

Excusetobooost

Thanks i was not sure at the moment so I went with the valvoline vr1 20W50 now it idles between 7-8psi instead of 4.. so there is some improvement. The weather is really hot currently.

turboLScrx

I’m @ .0025 on my mains , but I ported my oil pump and I shimmed it and I run 10w-30 with 20psi at full temp idle. It almost sounds like your mains are bigger than what was listed, I agree that a thicker oil should resolve the issue

Excusetobooost

Is it normal for the car to start sluggish with the thicker oil? After the 20W50 it like hesitates to idle but after it warms everything is normal. Im thinking of switch down to the 15W40.

turboLScrx

I think 20-50 is too think. We part of the country are you?

MastaFlyMason

iTrader: (1)

Hook up a real pressure gauge and test it. I had an eBay gauge that always read low, so I swapped it out to a ProSport gauge. Then after a couple weeks that gauge started reading low. I hooked a Harbor Freight tester up and my oil pressure was fine. Digital gauges seem to be junk, I've been through 3 with no luck. Thinking of getting one and just mounting it on the hood so I don't have to run an oil line into the cabin

turboLScrx

I agree. I only use mechanical gauges

Excusetobooost

I live in Philadelphia. I the pressure test gauge is a good idea..ill try that.

turboLScrx

20-50 is most used is very hot environments

Excusetobooost

I changed to the rotella and put the stock oil pressure sensor back in and have not had any issues. This week i will get the test gauge and check out the actual oil pressure. Thanks guys for all the info i will post an update.

Ntd3423

I have a fresh gsr css block as well i put 1000 miles on it. My bearing clearances are around .002 as well. New oem oil pump and squirter blockoff. Using a amazon sending unit to neptune rtp i see 80psi cold and 14 psi hot. I live in ft. Lauderdale and thats after a 45 min drive to westpalm beach. 95 degrees out. My cooling temp at 191. Im also using rotella 15w-40. Just so you have a comparison

khrys771

I have less than 100 miles on my CSS build, slightly looser bearing tolerances than stock (.0017) but not past the service limit. I am at 85 cold idle and mid 20s at 190 coolant temp. 80 degree weather This is on 5w30 oil.