Oil Question 1984 500SEL - Page 2 - PeachParts Mercedes-Benz Forum

RPM55 · #16 05-30-2013, 05:39 PM

The last I heard was that MB said .5 bar at idle speed with engine at operating temp was OK.

pmckechnie · #17 05-30-2013, 06:20 PM

Thanks RPM55. That makes me feel much better. I will change my gauge computer to make the low threshold 5 psi below 1000 RPM.
Thanks again

Paul

whunter · #18 06-01-2013, 02:14 PM

Quote:

Originally Posted by pmckechnie

Thanks RPM55. That makes me feel much better. I will change my gauge computer to make the low threshold 5 psi below 1000 RPM.
Thanks again

Paul

This is not OK.

0.5 Bar = 7.25 PSI

You raised the idle speed to around 600 rpm and the oil pressure went to 16 psi.

This does not surprise me.
Too many people reduce idle speed beyond OE SPEC, then:
* Have constant issues that can not be resolved (except when idle is raised).
* Have a catastrophic failure due to low idle.

Idle speed is assumed (engineering) to meet 600 - 750 RPM for:
* Minimum Alternator charge rate.
* Minimum water pump flow rate.
* Minimum engine mechanical cooling fan CFM rate.
* Minimum RPM for correct Power Steering operation.

.

pmckechnie · #19 06-01-2013, 05:13 PM

Thanks for the response Roy.
I have gone over this thing and can find no reason for the idle to be low. Remember, Idle is controlled by the idle control system on this engine. I have done nothing to lower the idle speed. I am going to try cleaning the intake system and throttle body with SeaFoam and see if that helps.
When I said I increased Idle speed to 600, I did that with the throttle peddle in the car. How do you increase the idle speed on this engine? I would love for it to be 600-650.

Paul

whunter · #20 06-01-2013, 11:19 PM

Cleaning the throttle plate and idle air control motor is a wise move.

I need to ask if all of this list was replaced with NEW, when you did the cylinder heads.

These parts are critical........

SCREENING, x8
MB# 1170700455
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

INTERMEDIATE PIECE, INTAKE MANIFOLD UPPER PART TO INTAKE MANIFOLD LOWER PART, x8
MB# 1171400265
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

These parts are important (common air leak points).

BOOT, FROM IDLE SPEED ACTUATOR TO CONNECTOR
MB# 1160941391
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

BOOT, FROM CYLINDER HEAD COVERTO CONNECTOR
MB# 1170940391
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

BOOT, FROM AIR DUCT TO IDLING ADJUSTER
MB# 1160941291
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

PLUG, DISTRIBUTOR LINE, LEFT AND RIGHT
MB# 1169971286
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

CONNECTOR, DISTRIBUTOR LINE, LEFT AND RIGHT, x2
MB# 1179900578
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

HOSE, DISTRIBUTOR LINE, LEFT AND RIGHT, x2
MB# 1160940982
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

HOSE, (DISTRIBUTOR LINE), IDLING AIR, x2
MB# 1160900582
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

I know you installed these two new, just noting the parts for future members.

GASKET, RIGHT
MB# 1171412380
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

GASKET LEFT
MB# 1171412480
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

.

pmckechnie · #21 06-02-2013, 08:51 AM

Roy
I bought this car around Jan, 2000 with 210k miles. It had a broken timing chain but was never fixed. It was used as a parts car for about 2 years. Most of the intake system and fuel system were missing. Cams were missing, etc. I found a 85 500 117 complete engine. I tore it down and rebuilt the heads to use on the original engine. I just put the intake and fuel system on the engine as they were. New timing chain and guides of course. Also, new oil pump and chain.
It ran good but did have the HIGH IDLE these engines are know for. I fixed leaks as they showed up. Then 12/2009 at 254k miles I removed the intake, cleaned it inside and out, replaced all the parts you ask about and some including new injectors. Smoke test showed no air leaks. Idle was good at around 600 rpm in gear, a little higher with the a/c on. I was happy
I really didn't pay much attention to idle speed after that because the car ran so good and you almost couldn't tell it was running at idle.
Now, at 278k it started this low oil pressure/low idle thing. It probably has nothing to do with it, but it started when I changed the oil using the 15W-50 instead of the 20W-50 I had been using. Nothing else has been done lately that should effect idle. The last thing done was the transmission was rebuilt about 2000 miles ago. Thinking about it, the torque converter may be a little tighter (lower stall speed) than the original. But the idle control should take care of that.
Yesterday I tried 2 other clean IAC spares and 1 controller I have with the same results.

Sorry for such a long post when a simple YES would have answered your question, but I wanted you to know a little history of the car.

Paul

whunter · #22 06-02-2013, 08:37 PM

Quote:

Originally Posted by pmckechnie

Roy
I bought this car around Jan, 2000 with 210k miles. It had a broken timing chain but was never fixed. It was used as a parts car for about 2 years. Most of the intake system and fuel system were missing. Cams were missing, etc. I found a 85 500 117 complete engine. I tore it down and rebuilt the heads to use on the original engine. I just put the intake and fuel system on the engine as they were. New timing chain and guides of course. Also, new oil pump and chain.
It ran good but did have the HIGH IDLE these engines are know for. I fixed leaks as they showed up. Then 12/2009 at 254k miles I removed the intake, cleaned it inside and out, replaced all the parts you ask about and some including new injectors. Smoke test showed no air leaks. Idle was good at around 600 rpm in gear, a little higher with the a/c on. I was happy
I really didn't pay much attention to idle speed after that because the car ran so good and you almost couldn't tell it was running at idle.
Now, at 278k it started this low oil pressure/low idle thing. It probably has nothing to do with it, but it started when I changed the oil using the 15W-50 instead of the 20W-50 I had been using. Nothing else has been done lately that should effect idle. The last thing done was the transmission was rebuilt about 2000 miles ago. Thinking about it, the torque converter may be a little tighter (lower stall speed) than the original. But the idle control should take care of that.
Yesterday I tried 2 other clean IAC spares and 1 controller I have with the same results.

Sorry for such a long post when a simple YES would have answered your question, but I wanted you to know a little history of the car.

Paul

Did you use the two documents I sent you for adjusting the idle?

.

pmckechnie · #23 06-02-2013, 09:09 PM

Yes, however it never mentioned LOW idle. I did go over all the checks they called out for and found no problems.

Paul

JamesDean · #24 06-03-2013, 10:35 AM

Quote:

Originally Posted by whunter

Idle speed is assumed (engineering) to meet 600 - 750 RPM for:
* Minimum Alternator charge rate.
* Minimum water pump flow rate.
* Minimum engine mechanical cooling fan CFM rate.
* Minimum RPM for correct Power Steering operation.

This 600-750 rpm idle, is that with the transmission in Park or in a gear?

Not to thread jack, but my 420SEL will idle about 800-900 in park but in the above 600-750 range when in gear.

pmckechnie · #25 06-03-2013, 01:03 PM

JamesDean,
I would like to know the same thing. My 500 is just like your 420, Around 800 in park and A/C off. In Drive, around 650. In drive and A/C on, about 560 since I cleaned the throttle body.
I haven't been able to find anything about the RPM in drive with A/C on. Should it still be in the 600 - 750 range?

Paul

whunter · #26 06-03-2013, 01:30 PM

Quote:

Originally Posted by pmckechnie

JamesDean,
I would like to know the same thing. My 500 is just like your 420, Around 800 in park and A/C off. In Drive, around 650. In drive and A/C on, about 560 since I cleaned the throttle body.
I haven't been able to find anything about the RPM in drive with A/C on. Should it still be in the 600 - 750 range?

Paul

If the engine is running; Minimum Idle = 600 - 750 RPM.

.

JamesDean · #27 06-03-2013, 01:32 PM

Quote:

Originally Posted by whunter

If the engine is running; Minimum Idle = 600 - 750 RPM.

.

So does that mean our engines are operating OK in park at 800rpm?

pmckechnie · #28 06-03-2013, 06:57 PM

I want to call this thread closed. I cleaned the throttle valve, IAC, and the rest of the intake track using seafoam through the intake. I was able to get the idle up to 570 - 580 in gear and A/C on. Oil pressure was up a little to 10psi (.7 bar). Next I drained the 15W50 Mobil 1 oil that started this mess and put in a new filter and 20W50 Royal Purple High Performance synthetic oil. The lowest oil pressure I have seen sense is 17 psi (1.2 bar) at 570 rpm, 200 deg F(93 deg C).
Just a note, I tried to think of how to increase the idle up to 600 - 750 and the only thing I could come up with is a new Idle Control Valve and a new Idle Control Controller. Cost $384 to $1108. That is for both, cheapest and most expensive. I think I will just get by with it the way it is now. 570 to 800 rpm at idle. After all, it is a 29 year old car with 278,000 miles.

Paul

whunter · #29 06-04-2013, 01:26 AM

Quote:

Originally Posted by JamesDean

So does that mean our engines are operating OK in park at 800rpm?

That is OK for the vintage control circuit.

.

pawoSD · #30 06-04-2013, 07:56 AM

After redoing all rubber on my M116 with 55k on it since rebuild....it idles hot around 1.5bar at 600rpm in drive, and about 2ish bar in park around 750rpm. This is on M1 15w50 synthetic. Similar results on my dad's M116 with 305k on the motor and running rotella T6.