# 8v oil light



## photo-tom (Jun 11, 2006)

86 golf 8v.
So I brought my car into the dealership to have some parts sorted out, had them change the oil while they were at it and asked them to use 10w40. I was driving home today and the oil light went on along with the buzzer. I pulled over and checked the oil. Not only did they overfill it but I looked at the order form and they used 5w30, too. Think that's what caused the pressure warning light or would it be something else? any input would help.
Thanks


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## Spade88 (Apr 18, 2008)

*Re: 8v oil light (sloppy2nds)*

I believe we are having the same problem, as I stated in my post, happened in my Cirrus after and oil change, and when I got it looked at, the guy said that there was oil spilt over the oil sensor, so I would most likely check that out first, nothing big, but also the worse case senario, it could quite possibley be the oil pump, but quite doubtfully unless she is idling really roughly... Get the oil sensor checked, and see from there. That is my plan







.


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## germancarnut51 (Mar 23, 2008)

*Re: 8v oil light (sloppy2nds)*

While 5W/30 is speccd for newer engines, an older engine like yours with higher mileage probably need a thicker oil to have acceptable oil pressure (if the engine is not worn out).
Did you have synthetic installed? Synthetic oil is very thin. Conventional oil is probably better in an older worn engine. How's the outside temperature? 30 weight oil is only recommended for 90F and lower. Maybe you should be running a 40W summer oil. 
Have the oil pressure checked with a mechanical pressure tester. Could be that your oil pressure sensor simply failed. Actually a friend of mine with a 89 Jetta recently had an alternator failure, and the resulting low voltage resulted in an oil pressure warning light. So, maybe you should have the alternator tested as well.
Did you have the timing belt replaced or tension adjusted? Maybe the oil pump is not being driven properly.


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## shipo (Jan 3, 2006)

*Re: 8v oil light (germancarnut51)*


_Quote, originally posted by *germancarnut51* »_Did you have synthetic installed? Synthetic oil is very thin. Conventional oil is probably better in an older worn engine.

So are you saying that a conventional 10W-40 oil will be "thicker" when up to operating temperature than say a 0W-40 synthetic?


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## volksrage13 (Oct 22, 2007)

*Re: 8v oil light (shipo)*

yea because the 10-40 is a 10 weight oil and the 0-40 is a 0 weight oil, they should carry the same ammount of 40 weight protection. 
but it could be the screen in the oil pump becoming cloged, does it turn on and shut off at different rpm's?


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## germancarnut51 (Mar 23, 2008)

*Re: 8v oil light (shipo)*

Yes, both oils are supposed to provide the same protection, but the synthetic oil is physically thinner, will provide less oil pressure at the same temperature, and leak where a conventional oil with the same weight rating will not.
It's not that the synthetic oil is breaking down at the rated temperature, it's just that it is thinner, so it will leak where a conventional oil will not. Kind of like the way that R12 refrigerant can stay in an ac system, and if you try to convert the same ac system to R134a, it leaks from places that the R12 never leaked from. R134a refrigerant gas particles are smaller, and they can leak both through the R12 rated hoses, and from small gaps in seals that will easily hold R12.


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## shipo (Jan 3, 2006)

*Re: 8v oil light (germancarnut51)*


_Quote, originally posted by *germancarnut51* »_Yes, both oils are supposed to provide the same protection, but the synthetic oil is physically thinner, will provide less oil pressure at the same temperature, and leak where a conventional oil with the same weight rating will not.

I'm sorry, but I have to reject what you've written. I've read many scientific papers published by the likes of the ACEA, API, SAE and the like, and I've never seen any evidence that suggests that a 0W-40 synthetic is any "thinner" (i.e. has a lower cSt) than say a 10W-40 conventional oil when up to operating temperature.
If you have any scientifically derived information that contradicts that, I'd love to see it.


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## germancarnut51 (Mar 23, 2008)

*Re: 8v oil light (shipo)*

How about getting off the keyboard and doing some research of your own?
Try buying a quart of synthetic 0W-40 and a quart or 10W-40 conventional motor oil and pouring equal amounts into identical clear glass jars. Then, jiggle the jars around. You are going to see that the 0W-40 motor oil is clearly thinner than the 10W-40.

Do you have a 10-year old or older car with over 100K miles on it?
If so, trying running synthetic 0W-40 for 3K miles, and then dump the oil and measure how much you get out. While you are accummulating the mileage, watch under the car for leaks.
Then, dump the oil and switch to a conventional 10W/40 motor oil, drive for 3K miles, and watch for leaks.
If you do, you will probably find new leaks and higher oil consumption with the synthetic oil.
Why would oil companies publish studies that show that synthetic oil will leak on older engines that conventional oil does not leak out of. The objective of their studies is to sell more synthetic motor oil, which would not be a accomplished with a studies that show that it leaks out of older engines.
Read you read anything about older engines from car owners, you will see that new oil leaks and higher oil usage is reported as common.
Funny how you don't see that from the oil companies.
The results of real life situations often contradict predictions/expectations from labrats who deal only in the theorical. 

_Modified by germancarnut51 at 11:06 AM 8-2-2008_


_Modified by germancarnut51 at 11:09 AM 8-2-2008_


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## photo-tom (Jun 11, 2006)

Well I found out that the oil warning light/buzzer goes off only when I am banging the car around clover leafs. But there were a couple cases yesterday when it went off for a split second when I got off the free way. So it maybe that the sensor itself has failed.
P.S. weather has been in the 90's here.


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## shipo (Jan 3, 2006)

*Re: 8v oil light (shipo)*


_Quote, originally posted by *germancarnut51* »_Try buying a quart of synthetic 0W-40 and a quart or 10W-40 conventional motor oil and pouring equal amounts into identical clear glass jars. Then, jiggle the jars around. You are going to see that the 0W-40 motor oil is clearly thinner than the 10W-40.

Are you for real? Where did I ever write that a 0W-40 synthetic wouldn't be thinner than a 10W-40 conventional oil. Dude, by definition, ANY 0W-40 (regardless of whether it's synthetic or conventional) will be thinner than ANY 10W-40 (once again regardless of whether it's synthetic or conventional) when cold.
For the record, I wrote the following:

_Quote, originally posted by *shipo* »_… I've never seen any evidence that suggests that a 0W-40 synthetic is any "thinner" (i.e. has a lower cSt) than say a 10W-40 conventional oil when up to operating temperature.

Said another way, the SAE J300 test specifies that a multigrade oil that is at 100C and has a viscosity of between 12.5 cSt and 16.3 cSt is a xW-40 weight oil, *regardless* of whether it is synthetic or not. If you care to look out in the market, you'll find any number of “something W forty” conventional oils that are "thinner" than any number of "something W forty" synthetic oils. Why is this so difficult to understand?


_Quote, originally posted by *germancarnut51* »_Do you have a 10-year old or older car with over 100K miles on it?

I have one that is ten years and one month with 160,000 miles on the clock and another that is five years and two months old with _only_ 112,000 miles on it.

_Quote, originally posted by *germancarnut51* »_If so, trying running synthetic 0W-40 for 3K miles, and then dump the oil and measure how much you get out. While you are accummulating the mileage, watch under the car for leaks.
Then, dump the oil and switch to a conventional 10W/40 motor oil, drive for 3K miles, and watch for leaks.
If you do, you will probably find new leaks and higher oil consumption with the synthetic oil.

Ridiculous assumption. Both of our cars run on Mobil 1 0W-40, both are treated to an oil change every ten to twelve thousand miles, neither engine leaks a drop of oil, however, I do need to add a single quart mid oil change to each engine.

_Quote, originally posted by *germancarnut51* »_Why would oil companies publish studies that show that synthetic oil will leak on older engines that conventional oil does not leak out of.

Where'd you get that little gem? Care to share a link?

_Quote, originally posted by *germancarnut51* »_The objective of their studies is to sell more synthetic motor oil, which would not be a accomplished with a studies that show that it leaks out of older engines.

Another little gem. Care to cite any references to support this one?

_Quote, originally posted by *germancarnut51* »_Read you read anything about older engines from car owners, you will see that new oil leaks and higher oil usage is reported as common.
Funny how you don't see that from the oil companies.
The results of real life situations often contradict predictions/expectations from labrats who deal only in the theorical.

Too funny, I've been turning wrenches for over three decades and have been following the synthetic oil market for the entire time, and I have yet to see any evidence to support your claims.

_Quote, originally posted by *germancarnut51* »_How about getting off the keyboard and doing some research of your own?

Donning my hat of condescension: Ummm, back at'cha babe.


_Modified by shipo at 5:29 PM 8-2-2008_


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## JETTASTREETRACER (Dec 1, 2007)

*Re: (sloppy2nds)*

actually yesterday i started getting the same problem yoiu have....im trying to find out. when it starts buzzing i rev the engine and it goes away....funny huh. lol u think the pump? please help. thoughts of lots of cash slippin out my pocket is bothering me.


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## jetta2u (Jun 18, 2002)

*Re: (JETTASTREETRACER)*

jetta you need to verify oil pressure with a gauge --it may be your oil pump-- it may be a clogged screen on the pump ,it could be the sensor---it could be bearings -- instead of guessing verify you have good oil pressure at the head


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## volksrage13 (Oct 22, 2007)

*Re: (jetta2u)*

oh word i have that same problem rev above like 2500 and it goes away every time
its done that for almost the entire time i have owned this car. i think im like 12000 miles on my conventional oil after swicthing back from synthetic.


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## 4ePikanini (Aug 29, 2007)

i had a oil pressure gauge installed and put castrol gold fully synthetic with high viscosity in and it leaked and had bad pressure.
Then researched and put in caltex delo 400 - blend - with lower viscosity and the leaks stopped and i got good pressure. Sludge dissappeared also.
I will never use any other oil except for caltex delo 400.
Google it and you will know why. - only read forums (whole discussions based on experience) for the truth.


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## volksrage13 (Oct 22, 2007)

*Re: (fourie_marius)*

sounds like they make a nice quality product
where does advanced autoparts get their oil from?


_Modified by volksrage13 at 7:12 PM 10-9-2008_


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## volkswagenfreakvr6 (Oct 4, 2008)

*Re: (volksrage13)*

Hey man ive had a few 8 valves when the light starts going on and off like that its usaully the oil pump especially with alot of miles if your over 120,000 throw an oil pump on and run 10 40 and a quart of lucas oil stabilazer, that engine will never die, i still have mine with 440,000 miles i stopped beating the **** out of it a while ago but it still fires up! OIl pumps arent too bad to do either, you have to prime the 8 vlave ones though just run oil threw.


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