Hello, I am new to this site but am glad I discovered it for I will be using it to learn alot about my blazer

I have a 2004 Blazer 6 cyl Four Wheel Drive Automatic at 110000 miles

My Blazer is slowly breaking down in various areas, but here is a question I cannot figure out why?

My oil pressure gauge maintains at medium pressure when my Blazer is running at whatever pace, which of course is normal. But when I step on the brakes or come to a temporary stop, my oil drops down to quarter pressure (low pressure), and when I step back on the accelerator, it jumps right back up to medium (normal) pressure. It has been doing this for the last couple days (300 miles). I checked the oil level, it is perfect, and i have clean oil and have always maintained using clean oil.

Any answers on why you believe this is happening would greatly appreciated, and hope I can fix this problem myself.

 

mine kinda did that before and it was fine after i changed the oil

 

Sounds like normal operation. A quick drop in engine RPM can have an associated drop in oil pressure.

The only way to really know is to get actual pressure readings.

 

Oil pressure.

Your oil pump is powered by the engine. Engine rpms go up the oil pump pumps faster. RPMS go down, oil pump turns slower. Faster the pump turns the higher the oil pressure, slower the pump turns the lower the oil pressure. Recommended oil pressure is 10 psi per 1000 rpms. Most 4.3 trucks idle at 40 psi, and hit 60 psi on the interstate, which is well above recommended. There are times when oil pressure will be above and below those numbers. Your numbers may be different under normal conditions. The key is to know your truck and know what is normal and what isn't. A change in oil pressure could be an early warning sign. Really depends on what has changed. It is nto uncommon for oil pressure to drop when oi levels falls too. On my Cavalier I could always tell when it was done 1/2 quart by watching the oil pressure. Rahter than top off, I changed the oil. Speaking of which I am over due on both the CAvalier and the Blazer. I could do those tomorrow while its raining out.

You say it has a 110,000 miles. Have you ever run some sort of oil treatment through the oil system just before an oil change? Every 100,000 miles I run a can of Marvelous Marvins Mystery Oil (basically kerosene) through the oil system. Pour it into the oil, let the engine idle for 10 minutes or so, drain oil, change filter, and top off with new oil. I do this for two oil changes in a row. Last 4.3 had 286,000 miles on it before I totaled the truck, and it still ran strong as the day I got it with 60,000 miles. This truck has 170,000 miles and still runs as strong as the day I got it with 27,000 miles on it.

Low oil pressure could be due to sludge build up, flush the system and see what happens.