# Low oil pressure at idle



## Caleb (May 19, 1999)

Guys I need some ideas here. I have a 91 GTI that has 160K miles on it. I have installed a Autometer oil pressure gauge in the car so I can keep a close eye on things, well today I noticed my oil light on the car flicker so I looked down at the gauge and I was running very low pressure at idle, around 5-8 psi. It was hard to tell since the gauge is not the accurate in the very low pressures but it was below 10 psi. Thing is that if I rev it up the pressure increases just like it is supposed to up to a normal pressure. This is just at idle that it has low pressure. At around 3000 rpm I run around 45 psi and that is still fine but if I rev it up and let it settle down to idle the oil light will just barely flicker. It has never down this before and I am kind of worried about it. Normally at idle I run a hair above 10 psi. Maybe between 10-15 psi. Oh and idle is around 850 rpm to 950 or so. I checked the level of course and everything is just fine there. I figure I am due for a oil change before long but I don't think that is it. Also I always run 10w-40 oil and nothing has changed there. What do you guys think? Are my rod and main bearings going out?


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## sccaITA16V (Nov 5, 2002)

*Re: Low oil pressure at idle (Caleb)*

my two cents. 1) 160K motor = old and tired oil pump. But don't run out and change it just yet. on to 2) 10w-40 is probably too light for an old and tired motor that was designed to run thicker oil viscosity. Try changing oil to something heavier like 15w-40 or 20w-50. Bet your problem will go away.
Good luck


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## mrkrad (Nov 9, 2000)

*Re: Low oil pressure at idle (sccaITA16V)*

put thicker oil in it.
maybe a new pump
but honestly it could be all the bearings, or rod bearings, or none.
sounds like it lived a hard 160K miles and maybe its time for a swap








or drive it till it dies.
when you have 0 at idle thats usually a spun rod bearing


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## ncvwnut (Jun 5, 2000)

*Re: Low oil pressure at idle (mrkrad)*

I wouldn't run thicker oil for very long. That is just a bandaid for the real problem. My rocco is old but still runs strong. I doubt the bearing and all are bad. Those engines are very bullet proof unless you run it without oil. My sister's engine went 295K with hotter cams and other upgraded goodies w/out needing to be rebuilt. Check the low pressure sensor first per the bentley manuel then if it is determined the oil pump is bad replace it. I failed to do that on my first VW and I lost 2 cylinders. It sucked but then again you live and learn.


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## Caleb (May 19, 1999)

*Re: Low oil pressure at idle (Caleb)*

Thanks for the reply guys. I think I will switch to 15w-40 and see if that does anything first. And I will also check out my low pressure switch and make sure it is good. After that if I still have a problem I might look into the oil pump but would the pump really be the problem? Like I said the pressure is normal everywhere except at idle.
Oh and I do understand that I have 160K on the car and it has been ran in a spirited way. I mean I did not put all those mods (see sig.) on for nothing







But I would still think that I would be ok. These things are bullet proof.


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## ncvwnut (Jun 5, 2000)

*Re: Low oil pressure at idle (Caleb)*

Don't ever count out the oil pump. But that is why you need to check the other stuff first. I did the same when my oil light would buzz and then go out. I used thicker oil and then one day it buzzed and the level was fine. Next thing I know the motor conks out on me. Pump and timing belt broke. Messed the whole car up.


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## mrkrad (Nov 9, 2000)

*Re: Low oil pressure at idle (ncvwnut)*

run 20w50w for summer man.
10w40 made my g60 oil light go off.
also use cheap paper filters or vw oem.
those super duper fram super filters will screw with your oil pressure.


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## Shad (Feb 8, 2003)

*Re: Low oil pressure at idle (Caleb)*

Maybe it's time to take out carter and cylinder head cover to clean things out. Oil might have turned into grease. It's common here in Brazil when people last too long between oil changes.


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## der_panzer (Apr 28, 2003)

*Re: Low oil pressure at idle (Caleb)*

Go for a new 36mm oil pump. That should fix you up.


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## be158 (Apr 4, 2003)

*Re: Low oil pressure at idle (der_panzer)*

the book of my 88' 1.8 8v says run 20w 50... prob since they run so hot


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## kickster (Aug 15, 2000)

*Re: Low oil pressure at idle (be158)*

My oil pressure is doing exact same thing. Since yesterday the oil light comes on at idle. the pressure gauge shows around 14 PSI at idle. As soon as I rev the car to 1000 rpm the light goes out. I am thinking my oil pump is on the way out. 
If the bearing is bad wouldnt make knocking sound?


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## rabbitgremlin (Sep 27, 2001)

*Re: Low oil pressure at idle (Caleb)*

hmmmm..... i'm confused now. wouldn't a lighter weight oil be thinner and easier to move, thus making the oil pressure lower?
i use only 5 weight with no problems. is this bad or what?!!
could your oil passages be constricted untill the oil warms up? maybe flushing the engine and then changing oil would help? 
do you know what temp the oil is running at? mine is about 80-85 degrees celsius.
barrett


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## rabbitgremlin (Sep 27, 2001)

*Re: Low oil pressure at idle (Caleb)*

i meant to say that a thinner oil wieght would make the pressure higher since it would be easier to move.
sorry.
barrett


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