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Engine Specific Info and Questions => IDI Engine => Topic started by: ORCoaster on February 06, 2019, 12:54:48 am
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I thought I had this problem figured out the other day but it happened to me again tonight on the way home.
As I leave work I drive slowly through a puddle of water that is about 3 inches deep. I know there is a place where there is a crack or a hole that causes the front end to drop a few inches so I don't want to be racing through and do damage to the car. But what happens as the front end does that quick drop is that I then loose oil pressure.
If I continue the few feet around the corner and turn the engine off then back on I can generally get the pressure to come back up again. Trying to figure out what is going on here.
I removed the vane style vacuum pump last weekend and shimmed it up so that the gear would not jump back up about a half an inch. I am wondering if the oil pump itself is loose from the block and dropping out of the vane pump. I did get a pair of vise grips on the shaft and pushed and pulled on it from above and didn't get any movement.
Just wondering if removing the pan and checking for a loose pump is worth laying in the rain in the driveway. I have other vehicles to drive but this needs to be fixed as I am looking to sell it in the spring.
Let me know if you have had this same problem and what the fix was that made it go away.
Thanks
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Maybe the oil is splashing and your plastic oil pump baffle has broken and allows air to be pulled in.
Oil level OK?
Got the right dipstick?
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The first time this happened I did pull the dipstick, it is the stock one, and it was a qt low so I added that much from the emergency bottle in the trunk. That stopped it from popping the light on, but I think it was more about the vac pump engaging with the oil shaft. I have the older diaphragm pump style vac pump on the engine. It is all in tip top shape as I just tore it apart to figure out why it was detaching from the oil pump drive shaft.
We are scheduled for rain for the next 3 to 4 days so laying on the driveway might be out unless I get on it first thing in the morning. I would have been able to do it today but swapped my work day from Sat to today so I didn't have to dig holes in the rain or lay on my back under a mobile home in the rain. Good that the Rabbit only needs to go a short distance to get me to work. The Caddy has brake issues so I am holding off on driving that for a bit. Need a new proportioning valve.
I think I will pull the pan and see if the pump is loose. That is the most direct route. It pumps good pressure as it gives me close to 100 psi on start up and about 40 at idle hot. I think I have adjusted the valve in the bottom of the pump in the past.
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Cannot belive this is still going!
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What the car or the problem?
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Any chance that the issue is wiring? I could see how a chafed wire in the sender circuit could ground out on a bump and give the symptom you describe.
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I had some very worrying oil light behavior 1000+ miles from home during my first post-AAZ road trip, which turned out to be a loose/damaged wire from the sender. It was intermittent but seemed RPM-dependent -- I was afraid to even hope that it was an electrical fault.
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I wish I could slap my forehead and go, Yah, that's it. But the oil pressure gauge at the top of the head is confirming the light on the dash. Gauge drops to zero as the red dot glows.
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Is the gauge mechanical or electrical?
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Mechanical, comes off a tee at the same place as the pressure switch, @ the head.
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Well, that's definitive then. In that position I'd pull the pan and see if I could see any issue with the pump or pickup tube.
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That's the plan, pull the pan. But with gusting winds of near 45 mph and rain being driven into the windows and down my neck right now I think I will hold off for a few days and let this storm track ride on by. I will update after I find something. Good or bad.
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Finally, an afternoon with sun and warmth enough to get under the car and pull the pan. After doing so I grabbed the oil pump and expected it to wiggle some. But no, nada, solid as a rock. I pulled on the pick up tube and the same thing. No movement at all.
I looked up under the pickup tube with a bright flashlight and there was nothing on the screen, nothing in the oil pan either that might have sucked up there then let go later. I looked in the little port for the high pressure relief and found nothing.
But that got me thinking, what if the pressure went up past the limit and then the little release mechanism didn't release? Would that allow the pressure to drop to zero? I can't understand why I would have lost oil pressure twice at nearly the same point in my route home.
The conditions would have been similar. cold engine, cold oil, same length of running time and same hard bump in the road.
Offer your theory if you care to do so. I am going to run it as it is and hope for the best.
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Maybe the low oil caused it to lose prime.
Try spinning the oil pump with a drill,
by removing the vacuum pump.
I've had to prime them when starting a fresh engine.
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It lost pressure after about a two minute idle and slow crawl down an ally. Did it twice same place. I have a mech gauge that showed 0 pressure when that happened. Once I shut the engine off it came right back. I have removed the vac pump, rotary style, and it is bolted up tight to the block. So I am not sure where it could disconnect between the two pumps.
I was down a quart the first time it happened but was on level ground all the while it idled up. Just going to watch the gauge a little bit more I guess.
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Well dang if it didn't do it again to me! Thurs night crawling out of the back alley, about a minute or two of engine running with no higher revs than to turn the Alternator on.
I did the same routine, turned out of the alley, and shut it down, and then a restart and all is fine. I thought about how I have both of the devices that tell me I have oil pressure teed off from the head. What if something is covering the small port on that head gallery? Then indeed both devices, mechanical gauge and oil sender unit, are going to give the same result. So I am hoping to move the mech gauge to another location and see what happens. If both go out again I might think about pulling the oil filter off and getting another. While I am at it I might flush the engine with some Seafoam or ATF. Then change oil.
This is so annoying.
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Hey Coaster, did you ever get this sorted out?
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Not yet, I have only a limited amount of time these days and without a garage or dry place to work I needed to chase down the problem of my brakes on the Caddy PU as I use it for most of my driving. I need to haul tools and such to and from work. So I am shooting to do the oil filter and stuff after this next round of rain rakes over us starting tomorrow evening or Weds.
I really wonder if I have a blown filter and the paper parts are moving around in the system or something. I also did look around for a second oil filter flange I thought I had. It had a place to take off a sending unit at the filter. I did find it but not the gasket that is sort of technical that goes with it. I think I will destroy the one on the engine if I go to replace the flange. I could make one I guess out of that thin gasket material. I think I have a large enough piece of that laying around here.
Thanks for asking, but like most of us having three sets of wheels can keep us busier than need be.
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Hope it turns out to be something simple. Have picked up a couple of used oil pressure senders before but never kept them because they had readings that were to low or just plain dead. Not sure how they can wear out and if you have the wiring for the oil light separate it is just a head scratch-er.
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Well ladies and gentlemen, I found the time to swap the sending units from the head and change oil and filter. I retained the VW sender in the head as I believe it was designed that way for a reason. Then I changed the oil filter flange to one of those styles that have the take off ports on top. I put my mechanical gauge on there.
I looked real hard at the oil as it flowed out of the oil pan, expecting gobs of something to come oozing out or even plugging the hole. Well NADA, It was warmed up a bit and I never noticed anything that would resemble part of the filter. I thought it had blown up in some way. I didn't cut it open to see if there was a problem with it. I didn't care to make a nasty mess with my cut off tool and didn't have the time to just cut it with a saw.
So what was the problem? I wish I could tell you. If it does it again at least I will be able to see if there is pressure lacking at the pump or just at the top of the engine. But honestly, I just want it to never do that again.
I did throw in some ATF fluid for a couple of days worth of short in town driving. I was looking for it to clean up some of the passages or take the crud out of the system. I put about 16 oz of Lucas oil treatment in with the change over this time hoping that will provide more lubrication should the pump crap out on me and I can't pull over right now.
Will post again if I have to.
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So my oil pressure gauge jumps up when i accelerate. Im thinking it might be the oil pressure sensor but Im not to sure? Its been like this since i bought the car last year and i dont hear any knockin noises witch is a good thing.ahaha. But if anyone has any input that would be great. Thanks-jb