Engine Oil pressure drop, in high heat conditions?

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HomerOz

HomerOz

Joined
Dec 8, 2017
Threads
29
Messages
515
Location
Australia
G'Day Fella's,

I went for a drive down to the south coast (of N.S.W. Australia), the other day (remember, it's Summer here at the moment).
I was on the highway, in my 1990 model BJ73 (3B engine, with 380,000 Kms on it), and the outside air temp was at times, 36* C (98* F).
I was hooting along at 100 Kph/60Mph, and noticed the engine oil pressure meter, had dropped a little (I was assuming, from the high air temp).
The engine water temp, was it's usual low level, according to it's meter.
I noticed when I went back into a slightly cooler forested area (30* C ish), the engine oil pressure rose back up (after a while), to it's nornmal operating pressure.

I was just wondering, would an engine oil cooling system, help with cooling the oil (OK, I know it's another Dumb Question from me) and increasing oil pressure, in this kind of heat?

Looking forward to any advice, you blokes can give me on this.

Here's another image of the Ole Girl, on another recent trip away up the mountains.
1901296


Regards
Homer
 
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What oil viscosity are you using? It is fairly normal for an old engine to lose some oil pressure on a hot day. You could use a thicker oil.
Oil pressure specs in the manual are fairly wide, about 30 psi minimum and 55 or so maximum at 2-3000 rpm
 
Old engine, hot weather, oil viscosity of 20-50 may be needed.
 
jmylie said:
hot weather, oil viscosity of 20-50 may be needed.
Click to expand...

Most people would be using that already. Its what the dealer sells. Hardly anyone uses 15/40 in older stye diesels here.
 
roscoFJ73 said:
Most people would be using that already. Its what the dealer sells. Hardly anyone uses 15/40 in older stye diesels here.
Click to expand...
I use full synthetic 5w-40 on my 2H year round :) It looks like I will probably not be driving my ute year round once the rust/paint repairs have been completed, so then I probably will switch to a 15w-40 maybe?
 
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G'Day Fella's,

Thank You again for your input, Very Much Appreciated.

I've been using Caltex, Delo 400, 15W-40 for decades, so maybe its time to go to a heavier grade oil.

Best regards
Homer
 
There are 2 different thermostat types for the 3bll..
One gives better heater / oil cooler opperation .
One runs hotter than the other . About 1/4 of the guage.
I have both some where but someone on this board mentioned it and i swapped too the colder one
 
If you look at 15-40 on a really hot day on the highway, its like water on the dipstick.
 
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