Gauges - what do they really say?

RobinL

RobinL

Member
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456
Ok so I work in an industry that is paranoid on gauges and generally we adjust (rotate) everything so the 'best reading' always has the needle at 12 o'clock - its easier to see when things are going wrong.

What I don't know is what, on my 2005 4200cc is a best reading? - OK Fuel is an easy one - before anybody helps with that one :canny:

What temperature is good for fully warmed up and 10/12 degrees outside - I'm seeing 85-90 degrees which to me seems a little low??
What Oil Pressure should I get - the needle is full right, max pressure, from start up (yes it goes to zero when I shut down)

Are these as expected for a 2005 car with just less than 30K on the clocks.

Cheers folks.

Robin
 
CatmanV2

CatmanV2

Member
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48,786
Temp is a tiny bit low, perhaps, but not enough that I'd worry, unless it was dropping at high speeds in cold weather. Or going up too much in hot traffic.

Oil pressure: Does it drop when the engine is properly hot? If not, you've got a problem with either your gauge or sender

C
 
Swedish Paul

Swedish Paul

Member
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1,810
Mine runs at 80-90 degrees and is fine, over 90 is an issue. Oil pressure should be 5 on start up and under load, drops to 2ish on tickover when fully warmed up.
 
R

RJ237

Member
Messages
107
I have a new oil sender and it drops to a little over 2 bar at idle, but by 2000 rpm it's back to max.
 
StuartW

StuartW

Member
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9,314
The senders are notriously fragile, I went through 2 in 2 years of ownership to the point that it was hard to reply on it get an accurate reading. At hot idle, don't be too concerned if the red low pressure light flickers on & off too - it's quite common
 
allandwf

allandwf

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10,994
I know exactly where you're coming from. We tilt gauges on panels also so normal reading is 12 o clock, so at a quick glance you know everything is correct.
 
philw696

philw696

Member
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25,439
It will be the sender unit for oil pressure for sure changed a few.
Why they stopped fitting capillary fed ones I don't know.
My old Daimler XJC gave me a fright with oil pressure put a capillary one one and happy days :)
 
mjheathcote

mjheathcote

Centenary Club
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9,038
Those figures look absolutely fine to me.
My ultragauge plugged into the OBDII port gives the same running temperatures.
 
RobinL

RobinL

Member
Messages
456
Many thanks for the information and views folks - appreciated. I'm not overly concerned as the engine is running just fine. Mike has a point though - I should just check out the OBD output (which I will do when I get back to UK)!
 
O

Oxytorch

Junior Member
Messages
122
OBD doesn't show oil pressure though. Only engine coolant temp.
When I bought my Gransport, it was filled with Selenia 10W/60 and the needle on the oil pressure gauge was always pegged at 5 bar. At the first service, I had the oil replaced with 5W/50. Here in the Brisbane summer where the daytime temp is over 30 C everyday, the oil pressure drops to just above or below 1.25 bar when in urban traffic with need coolant temp nudging just over 90 C. During the cooler months, the needle tends to sit halfway between 1.25 and 2.5 bar. I agree with others that it's a distracting gauge because it causes some anxiety when it drops below 1.25 bar. Should I be worried? Then again, there is something flaky about my oil pressure gauge - see my video. https://youtu.be/XOLj18a3eT4. Strangely, it only does this with ignition on engine off but not with engine running. I bought a replacement sender ages ago but haven't had the time to get it replaced.
J
 
philw696

philw696

Member
Messages
25,439
Sender unit is notoriously a week link so change it as soon as you can.
We use 10W60 in the dry sump engines and 3200 all other petrols use 5W40 and diesels 5W30 here in New Zealand.
 
allandwf

allandwf

Member
Messages
10,994
It looks like a typical dodgy connection in the sender, although it would need to see a drop in resistance for that to happen. Changing it out should fix that.
 
davy83

davy83

Member
Messages
2,823
philw696 said:
It will be the sender unit for oil pressure for sure changed a few.
Why they stopped fitting capillary fed ones I don't know.
My old Daimler XJC gave me a fright with oil pressure put a capillary one one and happy days :)
Click to expand...

Presumably the problem with capillary is the hydraulic line flexes and breaks and then dumps your oil all over the place? the good thing is you could mount the sensor away from the engine heat? what did these things look like? if it had a flexible pressure hose then this would be a cost problem, as these are not that cheap.
 
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