Where should the "oil gauge" be when idling? Also, temp gauge? - PeachParts Mercedes-Benz Forum

86560SEL · #1 12-13-2005, 09:09 PM

Did a search - no luck. This car is new to me, so I am still learning....

Can anyone tell me where the oil pressure needle should be when the engine on an 80s S-Class is fully warm and the car is idling in park? Also, what about when in gear? My car idles in gear at 500rpm. Is this RPM to low? I am just wondering about the oil pressure, because I am not sure where it is supposed to be. When cold, it tops out past "3" and even when warm when I accelerate it goes past "3". When idling in neutral, it is around "2" and when idling around 500 rpms it is between "1" and "2". I know my oil is old and needs changing, so that may make a difference.

Now, what about the temperature? When in slow/stopped city traffic, it is just below 80*C. When driving on the highway, it is between 80*C and the first line. Sometimes, it is just above the first line. Heat is hot however. Everything seems fine. I just want to know if this is normal operation.

Also- my middle muffler has a hole. Is this something that is going to cost $$$, or can a local independent shop just install a "standard" muffler? I guess I could call tomorrow, but wanted to get a bit of info here tonight about it.

Thanks!

420 SE · #2 12-13-2005, 09:25 PM

All your gauges are reading tickety-boo (just perfectly normal) as long as oil pressure is above 1 at idle, should be 3 with any throttle. Revs sound perfect. Temp is fine.

Cheers

86560SEL · #3 12-13-2005, 09:58 PM

What about idling in gear? @ 500 rpms? Still above "1"? What if the oil was old/thin? Would this make it read lower than it should? Thanks again!

t walgamuth · #4 12-13-2005, 10:00 PM

generic mufflers in times of not wanting to spend a lot. also if the back muff is fine you might just put in a straight pipe there and have a little rumble. on my 500sec (84) i have replaced the back muff with straight and it just rumbles a bit, not much but you can hear the v8.

good luck

tom w

420 SE · #5 12-13-2005, 10:06 PM

Quote:

Originally Posted by 86560SEL

What about idling in gear? @ 500 rpms? Still above "1"? What if the oil was old/thin? Would this make it read lower than it should? Thanks again!

That all sounds fine.

autozen · #6 12-13-2005, 10:16 PM

All of your readings are fine. I suggest you bite the bullet and go for original replacement on the exhaust. Yes, it is going to cost some bucks, but you are driving one of the finest automobiles ever produced for cheap. Any thing you can buy today is going to cost you over $30,000 and won't compare with what you have. If you cheap out on this, you really should get a good rice burner and give up on the 560 SEL, because you don't appreciate what you have. Check my bio.

Hatterasguy · #7 12-13-2005, 10:29 PM

MB specs .3 bar at hot idle for min oil pressure, the guage should peg at 3 bar by 3k rpm. These are the limits so if you are within them you are ok.

80C is about where they should run, however they may touch 100C on real hot days.

Fastlane seems to sell mufflers for your car from $150-$200 depending on model.

86560SEL · #8 12-13-2005, 11:10 PM

Thanks for the replies guys. Hattaras: can you clarify ".3 bar" @ hot idle? What is ".3"? I drove the car for the first time today on about a 18 mile trip and noticed a couple of times when I stopped at a traffic lamp that the gauge was dropping a little below the "1". I know my oil needs changed. It is BLACK. However, the moment I accelerate, it goes back to the peg above the "3". I do not think I ever had to take it to 3000 rpm either. It was on the "3" by about 1500 rpms. When it was idling in neutral, it was jst below the "2". I am sure these gauges are not prefectly accurate. My old 95' Suburban had a oil gauge that "danced" all over the place after the engine warmed.

As mentioned, I drove this car on the road for the first time today and was impressed. You may remember in another post, I had asked about the power on these cars. Well, I must say I am impressed. Like I said, I never took it over 3K rpms. I never had to. The transmission shifts very firmly from 1-2 when the car was cold, but after it warmed up, it shifted smoother, but it was not slipping. Shifts were noticable, but not neck jerking. I am guessing this is normal. I would not want it any firmer than that- nor any softer, but I am used to older, large American cars, with ultra smooth transmissions. In my 73' Pontiac, the shifts are unnoticable, same can be said for my 69' Caprice as well.

When I shift into "R" it is definitely noticable. I am guessing an adjustment is in order? Not a big deal though.

About the muffler- it is not that loud, but it is louder than it should be. Today, when the car was warming up (it was only in the 30s to lower 40s today) it was steaming (as normal) from the tailpipe, but there was some coming out from in front of the back tire area, so I know there is a hole there somewhere. True, these may be fine cars, but I do not want to pay $200 for a muffler, if I could get one as good for $50-$60. I may let it go for a while longer. As mentioned, it is not all that loud and I do not smell any exhaust fumes.

Did searches- no results to these:

Instead of starting new topics- I have a few of other questions:

#1- what is the rectangle box looking thing attached to the driver side of the radiator with braded hoses to it? One of the hoses on mine is cracked and I smell light gasoline fumes from it. Is it some sort of a vapor canister or something? (SEE PHOTO @ BOTTOM)

#2- I also notice if I park the car with the front headed uphill, the power steering pump will leak a bit. Is this a common problem on these cars? It may be a hose, I will have to investigate this further. If I want to add fluid, do I simply remove that cover and pour it in? Also, can I use tranny fluid, or MB power steering fluid only?

#3- The "anti-lock" warning lamp is illuminating. I did not notice this when the PO bought the car to me, but I have noticed it twice. One day when I moved it in the driveway and again today. Brakes seem fine.

Sorry, but these cars are totally new to me.

Photo of that box (referred to in question #1) is pictured here with a circle around it. This is not my engine, but one from an 83' 380SEL, but this is the same box I am referring to. I circled the actual unit in red and the hose on my car that is cracked in blue. That is where the smell is coming from. Not strong - you actually havet to get down to it to smell it. I was checking out the leak @ the PS pump when I noticed the smell.

Thanks in advance!

420 SE · #9 12-14-2005, 05:34 AM

OK, lots of questions, I'll answer the ones I know about.

Power steering fluid - I only use MB fluid - I may be throwing money away - and others will comment - but when I bought my car I had a PS leak. It's been repaired so I don't add fluid any more - yes, just top up the canister.

Rough shifting, could be an adjustment needed to the Bowen cable or a vacuum leak, bothe will do it - I've had my tranny rebuilt and have spent a few trips back to the workshop to have it adjusted.

Brakes, could just be a sensor on the ABS - could be more - have you tried an emergency stop to see if the ABS kicks in??

Brake symbol on when the park brake is off - check brake fluid, or maybe the sensor in the brake fluid resovour (unlikely).

Your oil pressure gauge should not drop below 1, 0.3 is almost at the bottom of the gauge.

Don't know what is in that pic you posted - but it's been a long day with a mini cyclone and loss of power for 5 hours, so I'm going to clean up around my house!

86560SEL · #10 12-14-2005, 09:33 AM

Thanks. Actually, the "brake" light is on because the emergency brake pedal is not staying all the way up. If I lift it, it goes out. Perhaps a weak spring, or whatever holds the pedal up.

The oil gauge did not go to near zero. It went slightly below "1" at the low idle when I stopped, but it went back up to "1" even when idling in drive. It went back up beyond "3" by 1500 rpms. Aside from some slight lifter tap from the right side of the engine, it is quiet. As mentioned, I know the oil needs changed, which I need to get to ASAP.

Off to work I go.....

Hatterasguy · #11 12-14-2005, 10:43 AM

.3 bar is .3 bar. It would be hard to read on the guage but with a mechanical one hooked up it shouldn't be a problem.

Thats what MB specs for the min oil pressure for hot idle. Most of these cars seem to be between 1-2 bar, depending on how tight the engines are and how accurite a 20 year old guage is.

Change the oil and don't worry about it.

tvpierce · #12 12-14-2005, 11:02 AM

Quote:

Originally Posted by Hatterasguy

.3 bar is .3 bar.

Just to expand on/clarify this: Consumers in the USA are accustom to pressure readings being represented in PSI (pounds per square inch). Your guage incriments on this car are in "bars". One "bar" equals about 14.7 psi
So MB's minimum spec of .3 bar (needle would be 1/3 the distance between 0 and 1) is a little less than 5 psi.

Hope that helps.

Jeff Pierce

86560SEL · #13 12-14-2005, 08:39 PM

Thanks for those replies. Seems all is well. Now, does anyone know what this "box" with is with hoses that I am referring to?

[QUOTE=86560SEL]
#1- what is the rectangle box looking thing attached to the driver side of the radiator with braded hoses to it? One of the hoses on mine is cracked and I smell light gasoline fumes from it. Is it some sort of a vapor canister or something? (SEE PHOTO @ BOTTOM)
QUOTE]

280Sbenz · #14 12-15-2005, 06:31 AM

the rectangle box you are referring to is your oil cooler if i am not mistaken. the two hoses that are connected to it go the oil filter and one to the rear of the block.

hope this helps

86560SEL · #15 12-15-2005, 09:06 AM

Thanks. Is it normal that it has a fuel smell from that cracked hose?