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low oil pressure in traffic congestions with tranny on D

Started by BCK1963, 29 March 2022, 12:10 AM

BCK1963

Hi all,

today I have been recommended to shift from D to N when standing in traffic congestions and the like as the depression of the idle and subsequently of the oil pressure would be risky for the lubrication.
The guy referred to his fathers's 1972 R 107 and a blown cylinder head gasket in that situation. He spoke of an idle difference of 300 - 400.

I cannot recall right now the exact differences in idle and oil pressure for my car: idle difference may be max. 200 rpm and oil pressure never goes down to a level which would frighten me.

Its the first time that I hear this. Any experiences or opinions in the community?

    cheers    Bernd
Bernd

1976 Merc 6.9  since 2013

rumb

There should be no need for shifting to neutral. As long as the oil pressure goes up when you accelerate.  Should be 1 bar for every 1000 rpm.

If a cars cooling system is in poor condition then slipping into neutral could help keep Temperature lower.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550, '16 AMG GTS

daantjie

The only info I have regarding shifting the transmission out of D when parked is if you are going to be parked for a long time due to for instance traffic congestion.  Keeping it in D when not moving raises the temp in the transmission to unfavourable temperatures.
Daniel
1977 450 SEL 6.9 - Astralsilber

ptashek

Quote from: rumb on 29 March 2022, 04:37 AMShould be 1 bar for every 1000 rpm

Not really.
At least 0.5 bar at idle, and maxing out as soon as you touch the throttle.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

ptashek

Quote from: BCK1963 on 29 March 2022, 12:10 AMIts the first time that I hear this. Any experiences or opinions in the community?

A couple minutes in D with the brake applied at a red light is perfectly fine. When the car is stationary in D, the torque converter goes into stall mode, a side effect of which is increase of transmission fluid temperature. It shouldn't pose an issue in normal use, on a car with properly working cooling system.

Never race the engine with brake applied and the transmission in D if you want the transmission to last.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE