Months ago, my oil gauge quit working properly on the 190E, so I had the pressure checked and planned on replacing the sending unit sometime.

I ordered the unit, but had not installed it yet. Then, last week, the voltage regulator ended it's life, (while Helen had the car in B.C.) and had to be replaced. Suddenly the oil pressure gauge works properly.

Go figure.

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John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

Hi John

Read your post with interest as the oil pressure indicator on my 560 malfunctioned a while back and now it seems my battery won't hold a charge. ( the abberent behavior of the guage was to peg at 3 as soon as the key was turned )

Are there any tricks to getting the little sucker off the back of the alternator or is it just a matter of getting off 2 screws and pulling straight out?

BTW there is a whole industry built on the premise of observed coincidence - featured on CNBC every day

Thanks for sharing.

Patrick

My oil pressure sendign unit also quit on me, and I just had it replaced less then a year ago, but I never had problems with charging or the voltage regulator and replacing the sending unit fixed the problem last time. Over time the gauge would start jumping up and down and eventually jumped out of scale apparently since now it's always on 3.

Is this common?

xp

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1985 190E 2.3L - a constant project.

Check out the 1st post in the following thread, then BenzMacs reply.

http://www.peachparts.com/shopforum/showthread.php?t=28241&highlight=regulator

I've seen similar replies here from other pros. I believe the current that goes thru the brushes(volt. reg.) also goes thru some of the circuitry in the dash.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

What a rasslin' match to get that little devil off.

Took it out from the alternator and checked the condition of the brushes and connections and such and found no visible problems. Is there any particular test to see if it's door-nailed, or is it a case of "if it blows it would be visibly apparent"?

Getting it back on was worse than getting it off as I had to pretty much go by "feel". If I do this again, I'll make sure I have enough time to take the alternator completely off and work on a bench instead.

Any other trouble shooting tips to tell whether or not it's the regulator rather than the whole alternator?

TIA

Patrick

Patrick:

The new Bosch brushes I've purchased are 1/2" long brand new.

2 phillips screws are removed - out comes the old - in goes the new.

Helps to put the front end of the car on ramps in order to access the back end of the alternator.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

John - you may have just saved me a lot of work. My 560sel is in storage all winter and it is only summer driven. When I took it out for a 30 mile drive for the first time this year the oil guage stayed pegged as normal. However on the return home trip it slowly started falling to the point it hit hit 1.5 bar when I got home. Turned the car off and on and it went up to 2.5 bar then jumped downward and settled in at 1-1.5 bar. Did this many times with turning ignition off then on again with same results. Next morning started it up and all was well - as soon as the engine was up to temp - the same needle drop happened again. Ordered a new oil sending unit and installed. same thing. Got busy on my other cars and put off fixing it until this week end. Did yours do the same thing? Could the answer be as simple as the brush pak in the alternator? I was getting ready to pull the instrument cluster and check all connections for a bad connection then go over all the body grounds.Then as a last resort was going to hook up a pressure guage to make sure the 60 lbs oil pressure was really there. The action of the guage hints more at electrical than mechanical problem. Please advise ASAP so I can pick up a brush pak if required
Many thanks
Morris

In ANY electrical system whether it is a computer, an electronic instrument of some sort or a car, whenever you are seeing malfunctions, the FIRST thing you check is your power supply.

In the case of a car, your power supply consists of the battery, alternator and voltage regulator.

Good luck,

I replaced mine in the 190E on Tuesday during lunch! Before replacement my battery wtih car running was at 13.7 V! After replacement I am getting 14.2! I had to re-adjust my mixture due to more voltage! Must have changed due to higher voltage and all things working in a better range I guess, since mixture is set mechanically and adjusted via EHA! So I take it more power made the EHA function better! Old regulator had oil caked in it from previous oil leak or when I replaced the timing chain tensioner and oil poored down on it! Oh well works now and that is all that matters.....

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

OK I must be jinxed. In my previous post I told you what my oil pressure guage was doing. I removed the regulator pak in the alternator and the brushes are 1/2" long - almost like new. Put it back in and checked the charging voltage. 13.37v at idle and 13.76 volts at 2000 rpm - this I accept as normal since the battery is on a Battery Minder maintainer all the time the car is no used so the battery is always fully charged. Engine reaches operating temp - same problem with oil pressure guage. Last fall before storage I had the dealership replace the timing chain tensioner and upper chain guides - did not have time - timing chain was changed earlier in the year. They also changed the oil and filter at the same time. They suggested and used Quaker State 10W30 along with a Mercedes brand oil filter - car had previously been using Pennsoil 10w30. With only 1200 miles on the oil change I decided to change the oil to Castrol Syntec 5w-50 and used a Mann filter. When I started the car the oil guage stayed at "0" for 2-3 seconds then shot up to 3 bar and stayed there. SUCCESS!! Drove the car for 100 miles and the needle stayed pegged> Yes-s-s-s It's cured! NOT. Now I have a different problem. Now instead of the needle falling slowly - it stays pegged. The new problem? As soon as the key is turned on - without starting the motor - the needle pegs at 3 bar and stays there - engine running or not - it drops to "0" when key is turned off. Since I already put in a new oil pressure sensor and cleaned and made sure the connections to it were good - WHAT GIVES?? This does not make sense - what should I check next???
Any help appreciated
Morris

In 1992 (don't know what month; will look it up tonight), in an edition of the "Star", Frank King relates several instances of oil pressure gauge problems related to voltage issues. Replacement of the voltage regulator cured the problems in those anecdotal accounts and mention was made of checking/replacement of the overvoltage protection relay. FWIW.

Morris, check connection to the sensor. Open contact results in a constant 3 bar reading.


EDIT: I was wrong (no big surprise there ) March/April 1993 issue and it dealt with temp. gauge. The basics of the article still apply

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Nope connection to the sensor is excellent. I removed the plastic cover and sanded the terminal, crimped it a little tighter and re-assembled and pushed it on with a "click" to the sensor. Any other ideas? If the OPV relay was bad causing the problem - where would I check the voltage and under what conditions - to determine if it was bad?
Thanks
Morris