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Question

I have a 1996 chevy s-10 blazer with a 4.3L W-vin code engine. I have just replaced the main and rod bearings .001" oversized tops and bottoms, and a high volumn oil pump a new one. All the bearing clearances we about .038mm plastic gauged. The oil pressure when i start the engine is 60psi. As the engine heats up the pressure goes down, but it is steady,60,50,40 until it is heated up. It will go to 20psi. and stay there. I am using 10w-40 oil quaker state. Someone told me that the camshaft bearings may be at fault. The engine has at least 150,000 miles on it. I rebuilt the engine 7 years ago.( bearings and oil pump). I don't know. What about using 15w-40 oil. Or lucas oil additives. Any suggestions.

Submitted: 164 days and 15 hours ago.
Category: Chevy
Value: $15
Status: CLOSED
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Optional Information

Year : 1996
Make : Chevrolet
Model : s-10 blazer
Engine : 4.3L vin.w

Already Tried:
nothing yet.

Posted by Vladgmru 164 days and 12 hours ago.

Answer

Hello BobMarty!
Thanks for choosing JustAnswer.
My name is Vladimir.
Yes, the camshaft bearings might be worn-out and it could be a reason for a low oil pressure issue, but in your case you have 20 PSI ( I suppose at idle) that three times exceeds minimum hot pressure specifications.
Below is the factory oil pressure (minimum hot) specifications and if your reading within these ranges, you should not use 15w-40 oil.
Concerning oil additives, you may use it on your own discretion.

6.0 psi at 1,000 engine rpm

18.0 psi at 2,000 engine rpm

24.0 psi at 4,000 engine rpm

Let me know if you need more information.

163 days and 17 hours ago.

Reply

Have you read my description. I ALREADY KNOW THESE SPECS YOU WROTE IN YOUR ANSWER. I HAVE NEW BEARINGS AND A HIGH VOLUMN OIL PUMP IN THE ENGINE. THE BEARINGS ARE ALL WITHIN SPECS FOR CLEARANCES I MADE SURE OF THAT. COULD ANY OTHER BEARING IN THE ENGINE BE CAUSING THIS PROBLEM OF 20 PSI AT IDLE AFTER ENGINE IS HOT.

Accepted Answer

Hi,
Yes, I have read you description.
A high volume does not mean high pressure.
I do not see any problem if you have 20 PSI at idle after engine is hot.
Any pump just pumps oil and has an oil relief valve that opens if the pressure exceeds certain value. This valve could be set at 55-60 PSI or 75-90 PSI ( probably your pump).This characteristic depends on a spring used in a pump. This pressure value just indicates a point when an oil relief valve opens in order to reduce pressure and does not mean that your oil pressure should be higher than a stock engine could have.
As said in my previous answer, the camshaft bearings could be a reason for a low oil pressure issue, but you have more than normal oil pressure at idle with the engine hot.
Did I miss something?

Picture
Expert: Vladgmru
Pos. Feedback: 100.0 %
Accepts: 176
Answered: 10/7/2009

Automotive Electrician

I've been working with American made cars since 1992.

162 days and 6 hours ago.

Reply

THE ONLY REASON I SAID THAT WAS MY ASTRO 05' HAS THE SAME ENGINE, WHEN IT IS HOT THE OIL PRESSURE GOES TO 30PSI. WHY. IT HAS 86,000 MI. ON IT. I AM GOING TO HOOK UP A MECHANICAL OIL PRESSURE GAUGE TO SEE WHAT THE OIL PRESSURE REALLY IS. THEN I WILL WRITE YOU BACK AND PAY FOR YOUR ANSMER. OK

Posted by Vladgmru 162 days and 5 hours ago.

Info Request

Hi,
Thanks for the reply.
Actually, I thought that you had already checked the oil pressure with a mechanical gauge.
Anyway, if you get something above 6 PSI at 1000 RPM, there will be no reason to worry.
I look forward to hearing from you.
Regards,
Vladimir.

161 days and 16 hours ago.

Reply

ok i will do that and let you know cold oil pressure and hot oil pressure. for the engine.

bob

Posted by Vladgmru 161 days and 13 hours ago.

Info Request

Hi Bob,
Sounds good.
I look forward to hearing from you.
Vladimir.

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