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jamiemulhall

jamiemulhall

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in a previous post i have gone on about oil temps etc.. but the green and red warning lights in the gauge keep comming on when the engine is hot in town i have had the alternator replaced all the cables etc etc when i am at idle the car burns a little oil (u can smell it) this is only when really hot it does it for a moment then stops and the oil lights go out and everything is fine.. this leans me to thinking it might be a oil pressure switch problem i have checked the oil cooler pipes and they are scalding as normal . when i go on a run the lights stay on then after a while go out the druck is ok 4bar under load and around 1 at idle i am using magnetec 10w 40 and the level is just below midway on the gauge when hot so everything on that side seems ok .. but my oil level gauge is straight up and has stopped working this is a recent event , anyway any advice would be appriciated
 
Hi Jamie

Thought I'd drop you a post in case you were thinking no-one is out here. I guess no-one knows the answer (I don't) so if it was me I would either call a specialist or book the car in for a diagnostic.

It might be an idea to put in a link to the opther post/ s so people can get the whole story.




 
It's ok Jerry the case is under investigation , I spoke on the phone with Jamie [8D]
 
Hi Jamie,
And as Jerry said there are people out there readind and thinking about your problems.
I think the short answer is to replace both the oil pressure switch and the oil tank level gauge and at least put these items in question to bed and if you try Porshe Apart for second hand units it shouldn't cost an arm and a leg.
If you are a DIY guy then a must is to purchase the Bentley workshop manual from the club shop, it's a must have book for the DIYer.

There are a lot of good things said in your note.
1) oil choice and grade, I have no problems with this.
2) Oil level on the dip stick when hot, this is fine and the only way to check the oil level. This also tells me that you have upwards of 13 Ltrs of oil in the system, more than enough for the proper cooling and protection of your engine. I have read that only 4 ltrs of oil at the correct pressure and temperature is all that is needed for SC enging protection. Your note said you haver 4 bar pressure when driving normally so I think this is also fine. At the moment we do not know about the oil temperature as a guide my car when hot runs with the pointer at the first marker point and will only move a mm above in traffic and will return to the first mark when I get going again.

I have three questions for you.
1) what is the idle speed when hot?
2)Where did you check the oil pipes that were scalding hot.was it under the front wheel arch?
3)What reading does your oil temperature gauge show when hot?

I personally pay no attention to the oil level gauge when driving as the oil in the tank is constantly changing . I check the gauge reading when I check the oil level on the dipstick after a run on tick over and the engine is hot. If the level on the dip stick says full then the oil gauge should say full ( its the same oil in the same tank) But as Bones has said you shoul run mid way between the marks on the dip stick for safety.

Still thinking Jamie let me know the answers to the questions.

Thats it for now
cheers
John.

 
thanks john

answers to your questions 1. 900 rpm (normal) in fact stays the same

2. checked the pipes under the sill where i sit they were hot

3. reading just on the top line of the box above cold (8th of the way up the gauge)

i think its the oil switch ( i have a small oil leak which drops on the exhaust when hot and burns off)
 
Hi Jamie,
1) My Bentley manual says 900 +/- 50 rpm so this looks good..
2) Oil pipes, This tells me that the Auxillary cooler thermostatic bypass valve is functioning.
3) Your temperature gauge reading looks the same as mine..

Changing the oil pressure switch is a simple thing to do, I would do this first.
You will at least put this item to bed.

Let us know hoe you get on.
Cheers
John


 
'Changing the oil pressure switch is a simple thing to do',

The oil pressure 'switch' ie the sender that operates the warning light is above the flywheel right at the back of the engine next to the engine mounted thermostat if you have a simple method for removing this please let me know for the future. The oil pressure 'gauge sender' is easy to change because that is right next to the fan, which one are we talking about here?
 
Hi Bones,
Before answering your note I thought I would get the third unpire to take a look at the problem.
The Bentley manual states that if " If the red oil pressure light comes on or flashes on while driving, always assume that the oil pressure is low"
It sounds like this is the situation Jamie has. So as a first step it is probably worth checking time out to check the oil pressure on a hot engine with a validated oil pressure gauge inserted in the oil pressure gauge sensor position next to the fan. The Bentley says that oil pressure should rise approximatley 10 PSI per 1000 rpm.
This is the third unpires recommendation so before changing parts it might be correct to go back to basics before moving on.
It certainly would give valuable information and if all is well give Jamie a comfortable feeling that his engine has no major issues re oil pressure.

Cheers
John
 
Hi Bones,
Quite right it is not an easy job to remove the pressure switch as I said sorry about this and the next time I have the car jacked up I will investigate further.
It is easy to change the oil pressure gauge sender as you have pointed out.

Cheers
John
 
If you remove the air cleaner and support the engine on a low troley jack, remove the two engine mounting bolts you can lower the engine enough to change the switch at the back the nuts are captivated on the sc.
 
Bernard,
Thanks for your reply.
You learn a lot from the Forum it just goes to show what a powerful tool it is.
Cheers
John
 
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