REALLY low oil pressure...

[Rodney87GN]

Over the past month I noticed my oil pressure at idle has dropped to 5-6 psi hot (approx. 195 degrees). When I first got the car it used to be 10-12 psi hot. Then a few months later it went down to 8-10 psi hot. Now it's at 5-6 psi. I know 8-10 psi is pretty normal for these cars, but at 5 psi I'm thinking something is wrong (or about to go wrong).

Oil pressure does go up with rpm, and I am at 10psi per 1000 rpm but barely.

I used 15W-50 Mobil 1 the whole time. I do not want to "band aid" the problem by running a thicker oil. I've read that the timing cover and oil pump clearances can open up over time causing low oil pressure. I'm going to pull off the pump and check it out but what else can cause this? Worn bearings? Cam?

 

[bison]

Drop the pan and inspect

 

[TURBOTERRORV6]

check if you have oil!,having insuffieciant oil will drop your oil pressure for a fact.

 

[ESP Products]

Have you done an oil change? ... does the oil pressure rise with an oil change? I've seen the nylon cam sprocket start to break apart and clog the oil filter. Inspect the filter.

Hope this helps you.

 

[dhjenkins]

Excessive clearance on the mains can cause low pressure, but you'd probably hear it via a knock or noisy lifters.

 

[87we410877]

i Had really low pressure and it was becuase i had all my anti freeze in the oil and it wiped out my mains cam and rod bearings. Drop the pan like said above and check the mains. Or just put oil in it if thats the case

 

[VadersV6]

Sounds like the clearances have been on the high side as long as you've had it. In the case of a machine shop going too big on clearances, then thicker oil wouldnt be a band-aid. Its necessary.

 

[Rodney87GN]

Thanks for the tips guys. Oil level is good, it was one of the first things I checked. Also there's no water in the oil. I'll do the oil change first since it's almost due for one and I'll cut open the filter. Maybe this time put in a thicker oil??

The previous owner rebuilt the motor and put in a 210/205 cam....so I'm ASSuming there should be an aftermarket timing chain and not a stock nylon one. I suppose it really is a loose motor, being it was rebuilt before. It does not make any knocking or ticking noises (yet) but I stopped driving the car for awhile until I find out what's going on.

If all else fails....off comes the oil pan.

 

[ckmm]

lom psi

i had a low oil psi. i change the oil pump and added a oil pump thrash plate from esp worked great psi at idle 25 to 30 driving 55 to 65 lbs

 

[Turbo RX-6]

FYI I read a really good article awhile ago about oils anf such and it said that running thicker 5-50 oil is not a fix for low oil pressure but can actually have the opposite effect. I'll try to find it. It has something to do with the thicker oil being more easily squeezed out of the bearing clearences.

 

[VadersV6]

FYI I read a really good article awhile ago about oils anf such and it said that running thicker 5-50 oil is not a fix for low oil pressure but can actually have the opposite effect. I'll try to find it. It has something to do with the thicker oil being more easily squeezed out of the bearing clearences.

Get a syringe and put water in it. Push the plunger and see how hard it is to squeeze out. Put honey in it and try it again. Thicker oil doesnt mean it will squeeze out easier. In the case of your 5W-50, yeah that would squeeze out easier cause when its hot it will be 5 weight. When its cold, it will be harder to pump and will take longer to drain back to the pan. I forgot what it is, but there was something about widening the spread between hot and cold weight being a bad combo. There are problems with oils like that, and your 5W-50 would be REALLY bad. Stock is 10W-30, and I run 20W-50. I used to have alot of valvetrain noise and a mysterious thunking coming from my rear main. After going to 20w-50, thats a distant memory. Ive put over 30,000 miles on the car with this weight and have no issues with it. I even add half a pint of valvoline SYN oil treatment which is super thick and has a better additive profile than GM EOS.
Jolly- Do you have any issues with running too rich? You could be thinning the oil out with gas. If your engine was built with loose clearances, a thicker oil wouldnt be a band aid like I said. It would be almost mandatory. There are some crappy shops out there that dont refer to the manual when machining an engine. They go with small block chevy clearances like idiots cause given the SBC is the god of all engines in their minds, those clearances are best on everything. But the TR engine needs alot of oil pressure at low rpms cause thats where all the load is...low in the rpm range. The cylinder pressures are enormous and high rpm oiling is not what you want. If some jackass machines the engine to loose SBC clearances, you'll have great oil pressure at an rpm you'll never reach. Dow low where you need it, it will be totally insufficient. The only way around this is to either go with a thicker oil, rebuild the engine with the right clearances and go back to the "right" weight oil, or go with a high volume pump and run the "right" weight oil. But if you do that, make sure to open up all the drain holes, or you'll end up draining the pan of oil at high rpm.

 

[Rodney87GN]

Jolly- Do you have any issues with running too rich? You could be thinning the oil out with gas. If your engine was built with loose clearances, a thicker oil wouldnt be a band aid like I said. It would be almost mandatory. There are some crappy shops out there that dont refer to the manual when machining an engine. They go with small block chevy clearances like idiots cause given the SBC is the god of all engines in their minds, those clearances are best on everything. But the TR engine needs alot of oil pressure at low rpms cause thats where all the load is...low in the rpm range. The cylinder pressures are enormous and high rpm oiling is not what you want. If some jackass machines the engine to loose SBC clearances, you'll have great oil pressure at an rpm you'll never reach. Dow low where you need it, it will be totally insufficient. The only way around this is to either go with a thicker oil, rebuild the engine with the right clearances and go back to the "right" weight oil, or go with a high volume pump and run the "right" weight oil. But if you do that, make sure to open up all the drain holes, or you'll end up draining the pan of oil at high rpm.

Great info Vader! My idle BLMs are at 119 (turbo tweak chip). I don't remember what they are driving around, I need to replay the datalog of that from 2 weeks ago. But it seems I'm not running excessively rich, the oil does not smell like gas. I also forgot to mention that I was gonna pull off the oil pump and check the clearances and timing cover for excess wear. Would a 20w-50 oil be a good oil for me to go to?

 

[Turbo6Smackdown]

Im not sure if this helps at all but... I used to run the turbo formulated amsoil stuff until it became unavailable... about 7 months or so ago, I developed a slight rod knock.. so, i ran a pf52 (the longer filter for our cars) and 6 quarts of 20w50 in her, and not only did it not quiet the knock, but over about 3 months, it actually got louder. So I decided to go back to the original way, using plain old 10w30 and the original pf47 with 5 quarts and it actually quieted the knock I still got the knock of course, but its a whole heck of a lot quieter now though. Sorry to confuse ya.

 

[VadersV6]

Im not sure if this helps at all but... I used to run the turbo formulated amsoil stuff until it became unavailable... about 7 months or so ago, I developed a slight rod knock.. so, i ran a pf52 (the longer filter for our cars) and 6 quarts of 20w50 in her, and not only did it not quiet the knock, but over about 3 months, it actually got louder. So I decided to go back to the original way, using plain old 10w30 and the original pf47 with 5 quarts and it actually quieted the knock I still got the knock of course, but its a whole heck of a lot quieter now though. Sorry to confuse ya.

The knock got louder cause you have engine damage and kept driving it. Engine damage doesnt improve with time. Run the correct oil filter. I have doubts about these other filters. I tried it once and noticed the filter spun on too loose..there was alot of clearance between the threaded hole on the filter and the filter adapter. If its not a tight sealed thread, raw unfiltered oil is slipping past everything. Kinda defreats the purpose. I run the stock style K&N filter now...nice tight fit.

 

[Turbo6Smackdown]

i understand the bearings probabaly wore a tad more ( i rarely drive my car at all) but, why, after switching from 6 qts of thick oil with a longer filter, to 5 qts of 10w30 with a stock length filter, did the slight knocking noise get significantly quieter? That's what stumped me.

 

[ESP Products]

but, why, after switching from 6 qts of thick oil with a longer filter, to 5 qts of 10w30 with a stock length filter, did the slight knocking noise get significantly quieter? That's what stumped me.

When your engine is shut down, and for a few days at a time, your oil drains back to the pan. The thicker oil is harder to move upon initial start-up. The same goes for the longer filter (longer time). Now couple this with your excessive clearances and you have your noise. We have used a Pre/Post-Lubrication system for years on our shop car and we have 4 Buicks at our shop now with the same kit on them. We, and our customers, never get a dry start. The exclusive Post-Cycle feature also assists in the turbo cool-down and eliminates coke in the bearing housing. The use of this system greatly extends the life of your engine and turbochrger; ultimately saving you thousands of dollars.

Hope this helps you.

 

[Ormand]

In the case of your 5W-50, yeah that would squeeze out easier cause when its hot it will be 5 weight.

That's backwards. In a multi-vis oil, the first number is the COLD viscosity. At low temps, the oil would be as thin as 5W, but at high temps, it will not thin out as quickly, so it will be only as thin as 50W.

 

[VadersV6]

That's backwards. In a multi-vis oil, the first number is the COLD viscosity. At low temps, the oil would be as thin as 5W, but at high temps, it will not thin out as quickly, so it will be only as thin as 50W.

This would be the first time ive seen oil get thicker when its hot and thinner when its cold. Kinda defies thermodynamics. 5w-50 means that the oil wont get thinner than 5 weight when its hot and wont get thicker than 50 when its cold.

 

[Turbo6Smackdown]

i understand the cold start up noise... i work on cars (mostly change oil) for a living.. i do it all day every day. MY problem is, NOT at startup, but all day while its running. Thicker oil/longer filter, louder noise.... smaller filter/thinner oil, quiter noise.. ALL while its running. all day. Thats what stumps me.

And about your thermodynamics question.. the lower number, or the first number is viscosity at startup, the second number, is viscosity at operating temperature. Does oil get thicker when it heats up? Yes. The polymers actually unwind with heat. And wind back up when its cold. Thermodynamics only governs some liquids sometimes.. Not ALL the time.
True, the liquid does get thinner, but the polymers unwind as well. So that evens it out. If it actually got thinner at OT, the engine would get 30,000 miles of wear within 15,000 miles.. If its 30 weight oil, it will stay 30 weight while at OT.

 

[Rodney87GN]

Just a quick update...I went ahead and did an oil change. I noticed some gold flakes when I drained the oil. I guess that's the bearing material. Is that normal to have some gold flakes in the oil? I also cut open the oil filter...it was pretty dirty and you can see some traces of gold flakes on the element.

I put in a K&N oil filter and dumped in some Valvoline 20W-50 dino oil. Now I have 15 psi hot oil pressure. I drove it around town to see if it drop and it did not.

I suppose the combination of a new oil filter and thicker oil helped but I'm a bit concerned about the gold flakes in the oil. I wonder what potential damage might have occured. And most importantly would it be okay to continue driving the car?