Volkswagen Cabriolet:

Low oil pressure

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# 1  1/20/2012 6:39 AM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Low oil pressure

Everyone,

New to this forum and find it most helpful but I have and issue i can't seem to figure out.

I have a 1986 VW Cabriolet Karmann edition 1.8 L engine.

Recently, wife was driving car when the gasket for the engine oil water cooler blew out on her. I am assuming that the unknown truth is that the car was continued to be driven as the engine died out on her leaving just enough car momentum to pull head first into a spot.

I went to get car and when turning the key only a click was heard. So i towed the car back home.

I poured some Kano Kr-oil and WD40 in the oil fill and let it sit overnight thinking that was not going to work.

However in the true spirit of this little car the next day she turned over and started when i noticed where the leak was.

I changed that gasket and drained and flushed the oil refilling with 10w 30 as before. The previous filter was a Fram and I replaced it with one since changing it to an STP filter due to info found on the forum. At this point I ran the car, The oil pressure was at 5 bar like normal at startup and then started to decrease as car warmed up to a temp of about 110 C according to the gauges then dropped steadily until it was low enough to set off the light and the buzzer when I revved the engine to 2000 rpm.

Checked the switches and they coincided with the gauge readings which was verified by screwing a gauge in the block. So I figured perhaps the pump went bad because of the engine oil was low or had no oil.

So I dropped the pan and changed the pump and gasket. The only thing I had in the pan was a slight amount (very slight) of shavings. Which I considered not to be a lot considering the age of the engine. The mileage is @ 110,000.

Restarted the car this time with 20w 50 and another STP filter.

Same problem although the issue takes a little longer to achieve the result. I removed the sensor again and connected a hose and adapter to run from the block to the oil fill to actually see if oil was flowing. It indeed is and does correspond with the increase in rpm.

So now I am stumped. I did look at the cooler and noticed that Bentley suggests to change the cooler if any metal shaving is found in pan. But I really had nothing really to speak of. Of the two hoses on the cooler the top one is too hot to touch and the bottom one is bearable upon about 10-20 minutes of running the engine. Could this be clogged and thus losing the pressure?

I have absolutely no leaks and the engine has no knocking what so ever.

I humbly ask for your opinions before I am willing to lay this car to rest. After the new top, tires, struts, rotors, and I really would hate to quit on this car. Thanks in advance for just reading and hopefully the help. sad

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# 2  1/20/2012 12:30 PM

TechHelp2
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Registered: 11/24/2009
Posts: 1299

Re: Low oil pressure

The first thing I would do is go get a factory oil filter and install it on your car. The cheaper oil filters are known to give engines lower oil pressure. If you can't get to a dealer then see if you can find a oil filter brand named WIX, they are a very good brand.

The oil cooler being hot on one hose and cooler on the other indicates to me that it is cooling the oil because of the one cooler hose. If you can take the hoses and gently blow air into the cooler, this could tell you if the cooler has a clog in it. I don't think it has anything to do with oil pressure.

Try a different oil filter before you go crazy. I have had in my 30 year experience that the dealer brand is the best to try first before you start doing any expensive repairs.

Get back to me with the results and we can go on from there.


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# 3  1/20/2012 3:39 PM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Re: Low oil pressure

Will get right on this. Thank you so much. My question for the clog on the cooler is not only the flow of antifreeze through it but there are small holes on the top of the cooler and also on the bottom.

I know the dimples on top of the cooler hold the gasket in place and prevent the over tightening of the cooler so as not to crush it. But does oil flow through this section of the cooler as well? The Bentley manual is not clear on this.

But I will try the filter first and run the results back to you.

Again thanks so much for taking the time to help.

The body on this car is excellent and this car was always a pleasure I hate to have to get rid of it.

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# 4  1/20/2012 10:10 PM

TechHelp2
Administrator
Registered: 11/24/2009
Posts: 1299

Re: Low oil pressure

The information I have is also limited and am not sure of the oil flow. I wouldn't worry about the cooler yet because this doesn't appear to be the loss of oil pressure.

Work on the oil pressure problem first then worry about the oil cooler later.

Keep me informed on your progress.


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# 5  1/21/2012 7:07 PM

Administrator
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Registered: 9/27/2008
Posts: 1279

Re: Low oil pressure

Keep in mind that if the engine was run with no oil for a long period of time, and metal shavings were found in the oil, chances are there is damage throughout the engine. Excessively worn bearings/journals (especially camshaft) will cause low oil pressure.


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# 6  1/22/2012 3:44 AM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Re: Low oil pressure

That was a concern of mine. But the metal shavings are so minimal for an engine at over a 100,000 miles. I am hoping that is normal as the shavings were not even in the oil pump screen. I understand that even minimal wear could cause a drop but I will try the filter first. Just got an original VW filter that was in my "spare parts" from the previous owner. The snow messed me up as I did not want to put the car on ramps with snow and ice. Before I rip the camshaft apart I really am hoping this reliable engine didn't get that far. (fingers crossed) Thanks though. I will freeze my chops off tomorrow to update this.

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# 7  1/23/2012 11:59 PM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Re: Low oil pressure

OK update. I switched the oil filter to the OEM filter and started it up again. Again there are no knocks, pings or abnormal noise of any kind. Pressure starts at 5 bar as usual and then over a 10 to 15 minute idling time she drops down to 1 bar at 2000 rpm and .5 bar at idle. Hitting the gas will reflect on the gauges and turn off the lights temporarily.
When I had the filter off I looked in the cooler hole and there is a spring in there (assuming it opens the water flow) it looked kind of cruddy so since the oil does pass through there I am wondering (among a million other things at this point) if there is some sort of restriction taking place in there. But then again the more I look at it the more confusing it gets. At least I know it is not the filter at this point, Thanks TechHelp2

Also in the fall I did change the water pump but doubt there is any relevance to that. But I do want you to have all the info possible.

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# 8  1/24/2012 12:31 AM

TechHelp2
Administrator
Registered: 11/24/2009
Posts: 1299

Re: Low oil pressure

I have a question, are you relying on the gauge in the car?

Can you take an oil pressure reading from an oil galley in the engine or remove the oil pressure switch and take if from there.

The oil pressure should be 29 PSI (2BAR) and minimum of 1 BAR at 2000 RPM.

You can still have engine damage in the form of camshaft bearings. If the cam shaft bearings are damaged you can get the low oil pressure readings your getting and have hardly any noise.

I know this is bad news but you would need to rule out a bad oil pressure switch.

The oil flow in an engine usually flows from the oil pump to the filter then goes to the camshaft bearings then flows down to the crank shaft bearings.

Keep us posted.


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# 9  1/24/2012 3:58 AM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Re: Low oil pressure

At first the issue was noticed on the console gauges. I suspected them and ran a gauge from the low pressure side of the block. The console gauges were almost dead on. so since then I reinstalled the switch and removed the gauge.

Prior to reinstalling the switch I hooked up a 1/4 in tubing to the hole and I can see the oil flowing and responding to the accelerator. Even after the change to 20w 50 and a can of the honey like oil did not increase pressure.

Where is the bypass valve and the pressure relief located exactly? The Bentley manual does not do a good job on showing it.

Your losing me on this, the oil flow in an engine usually flows from the oil pump to the filter then goes to the camshaft bearings then flows down to the crank shaft bearings never mind get it now for some reason I read camshaft twice. Aside from the Bentley diagrams does anyone have a shop manual that can post the diagram of this.

I have read it is possible to replace the  camshaft bearings without removing the engine. But there is a special tool involved. Is it possible?

What would something like this (estimated) cost at a VW dealer? (bearings)


I may buy a 4 door Golf for the wife in the meantime as with two kids the car seats are a pain in the cabby but I don't want to dump the issue on someone else nor give up on this car.

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# 10  1/24/2012 4:24 AM

jsvokowest
New member
Registered: 1/20/2012
Posts: 7

Re: Low oil pressure

Also sorry to drag it on but the Bar reading. Are you talking about taking the reading on the low or the high pressure side. The low pressure is the only one that sends the reading to the console gauge correct? This is where I put the gauge.

Could the viscosity of the oil  get so thin after 15 minutes to drop from 5 bar to 1 bar? I can't help but think that the pressure would at least start at say 3 bar and then drop to 1 bar after warm up but the cold pressure is the same as it was prior to the faulty cooler gasket. Being that the filter is never bypassed nor are the bearings I don't get the image of whats happening. I can see that perhaps as the engine heats the oil becomes thinner and perhaps the metal of the bearings are affected. But by so much and almost on a logarithmic scale of a drop seems odd.

That is why i am wondering if the large hole that has the spring in the cooler has some sort of flow restriction. I don't know just throwing it out for thought.

https://www.realworldautomotive.com/forums/uploads/thumbs/2507_068117021bmy.jpg

My assumption is once I am in the engine itself there is no turning back and might as well go ahead for an overhaul or maybe I am better just dropping a rebuilt in there.

Last edited by jsvokowest (1/24/2012 4:29 AM)

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