jake63

Please pardon me . I am a 63 yr old man that had a stroke 3 months ago. My writing my not be the best now.
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During the last couple of months my 1997 chev express van was not used when I was hospitalized and recuperating.
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It is a 5.7 liter v8. 153,000 miles and in good condition. It doesn’t use any oil and doesn’t smoke at all. It uses about a quart of oil for 1,000 miles. It starts every time.
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Doing the last couple of years I have gotten a single lifter tick only when the weather is above freezing. It only does that 20 or 30 seconds until it gets some oil.
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The oil pressure is always 60 pounds when the engine has not started (cold) and temp is summer and winter, and at idle.
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After the engine warms up, after running 10 for 15 min, it drops down to 45 pounds if the speed is 45 mph or more.
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It used to be 17 pounds when warm and idle at a stop light. When I drove it yesterday this was true.
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I noticed today the dash light went on. I noticed the oil pressure was about 5 to 6 pounds. I let the rpms go up a little and the oil pressure went up and light went off.
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It seems the engine is to good running, strong and quiet to have to much oil pressure at normal operations to have the oil pressure to drop so low at lower speeds and idle.
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It has been a long time since I have had any mechanical problem of this sort. Decades, since I worked on an engine with this magnitude.
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In my day, when I was younger, engines would smoke, burn and drip oil when the oil pressure was low.
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I would like any answers or solutions for problem. I hope this doesn’t requires an overhaul.
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Thanks

MDTAHOE

You need to have a mechanical oil pressure test done to see if the problem is the pressure sender or the engine.

jake63

I was going to try checking the sender. I have not found out if the sender could behave like that when bad.

Thanks

SWHouston

Greetings Jake, welcome to the Forum !

It's certainly important to eliminate the mechanical issues as MDTAHOE has stated, and I, unfortunately can only add a very little here.

Changing to a heavy Multi-Viscosity oil, may provide some increase.

When running about 30 mph with throttle applied, look at your pressure. Then let off the throttle suddenly. An immediate increase in pressure usually indicates bad Main Bearings.

One of the least expensive fixes, is to drop the Oil Pan, and have just the Rod and Main Bearings replaced. And gives you the opportunity to inspect the Oil Pump.

jake63

Took a well to get back to the forum. Everything seems breaking down this fall. Computer took a dump of its video drivers.
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I thought the oil pressure switch was bad, but I didn’t know its quirks.
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Since I could not find my mechanical oil pressure gauge, I just decided to buy an oil pressure switch from Autozone.
<o></o>As soon as I left the Autozone parking lot, the old pressure switch starting working again.
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New oil pressure switch readings.

Van at 165 degrees operating temp.
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Highway – 62 pounds pressure
Driving 25 mph in traffic – 40 pounds pressure
Idle at stop sign – 28 pounds pressure
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Thanks!

SWHouston

Jake,

The readings you just gave are still a little curious. They're not very consistent compared to the ones you gave in your first post. I think you still need to find your Mechanical Pressure Gage, and do a direct test. (Idle-1000rpm-2000rpm)

The curious part about this is...
The considerable differences in your Idle Pressure. The 28 lbs you just mentioned is not all that bad, but, the 6 lbs is. And at this time, I'm not sure weather it was actually the sender, or your Idle has increased a little for some reason.

I'm going to go out on a limb here a little, and bring up the Bearing Change again. At 153K, it's quite possible that a new set of Mains and Rods will help things considerably. Is that something you can do yourself ?

I'll point out one other thing concerning Main and Rod Bearings...
They do make "Undersized" inserts for both. BUT, you really have to be careful about your measurements of the Journals, to determine if you can handle an undersized. If you've never done this before, then stick with the Standard Replacement Size. That's certainly a move in the right direction.

One more thing...
Is the cost of these repairs, really going to be worth it on that old of a Vehicle, or, do you need to be looking for something newer ?

jake63

The first readings were bad readings too because of the bad switch. Apparently it has been giving bad readings for a long time.

The weird readings is why I wanted to know how these pressure switch and gauge behaved when going bad.

I am a service connected disabled veteran on SS and VA disability. Since Obama froze SS and VA disability cost of living increases for 2 years in a row now, I can not do any thing right now.

I was planning on this auto to be my last one. If it bites the dust I will have to drive my 96 dodge ram diesel. I do not like to drive it because of my back.

They readings could be better, but it has 153,000 miles. It's quiet and smooth running, does not smoke, use oil or leak oil. I am satisfied with the current readings.