R32 Gtr Fluctuating Oil Pressure

[turbo_brian]

ok guys, another 32 with fluctuating oil pressure readings from the guage.

Been doing some reading and searching on here, and the majority feel is the bloody pressure sender, and seems to be a VERY common fault.

Anyway, here is my plite.

Have my lovely R32 GTR, did an oil change, and a few days later, I have noticed that sometimes (not all the time) the oil pressure gauge seems to show the pressure as being close to (but not quite) zero.

The oil used in the change was Mobil 1 SuperSyn (not sure of the weights, but will check), not sure if it might be too thin for the engine, causing it to have slightly lower pressure to normal.

I also suspect the oil pressure sender, as it's probably the stock original unit, does the R31 RB30E unit fit as a direct replacement, because I have a new sender on my RB30 which is sitting gathering dust unregistered, and I can rake parts from that if needed.

I also know the Oil pump was replaced about 10,000kms ago in this car for a new unit with sleeve, so I am shy-ing away from the oil pump being a problem at this stage.

Car is getting a mechanical oil pressure gauge to confirm the pressures today, but it still chill's me to see oil pressure drop low on such a motor.

Anyway, main question is will the RB30E oil pressure sender fit as a replacement to the R32 RB26DETT unit, or should I scrap the stock and shove an aftermarket unit in instead?

Thanks in advance and Merry xmas all.

B.

[ashr32]

its the sender mate, mine was exactly the same. i did the mechanical test and all is fine, i put an after market (autogauge) pressure unit in the stock location and it reads perfect.

good luck

[__PhaseShiftDown]

The weight of the oil affects the pressure reading. The quality of the oil also affects the reading slightly.

I have the same car (unopened engine with 80k on the clock) and I was using Castrol Edge 5w30 for about 3000k, and noticed the oil pressure is quiet low (sits on 1 sometimes) and increased to 3 when I drive it a bit hard and on highway, but it would fall lowish to ~1 after that.

I then switched to the same oil but 10w60 and saw the pressure stays mostly just very slightly above 2, and would climb to just under 4 when driven hard, but it would sometimes, very rarely falls to ~1 after that. Car also feels laggy as well, so I think its not the right weight of oil, even though on the castrol website, it recommended it.

So the last oil change, I switched over to Motul 300v 10w40 and found that the oil pressure is a lot stable. On idle and normal driving, it would sit on or just under 2, and climbs just a little bit over 2. When driven hard, it would climb to 3 at the maximum and falls back down to the 2 after that, so the pressure is a lot stable. Car also feels more responsive then when I was on 10w60. After reading all the article on oil base stock and actually seeing the difference myself, I will only ever use 300v in my car now. :-)

Btw, I think its better to get a good quality electric oil pressure gauge instead of the mechanical gauge, since I don't particularly like the idea of running hot oil straight into the cabin.

[turbo_brian]

Btw, I think its better to get a good quality electric oil pressure gauge instead of the mechanical gauge, since I don't particularly like the idea of running hot oil straight into the cabin.

Defiantely sound advise, it's also defectable to route engine bay fluids into the cabin, let alone the potential for failure.

I will be investing in an electronic oil pressure gauge shortly, will be using the mechanical gauge ONLY to confirm the current situation, to make sure my engine is not going to let go at some stage.

B.

[Risking]

its a GTR the engine is destined to let go at some point.

Oil weights play a major role in hot pressures. I use nothing but the edge 10W60 in the RB as I have had oil test samples done from several oil brands and its results were the best for my application.

It does sound like you have a sender issue and No the RB30 sender doesnt work. Its just a simple idiot light switch and cant opperate the guage in the GTR.

Did you ever check the pressure with a proper guage??

[turbo_brian]

Got the pressure checked with a mechanical guage, have the figures at home, pretty decent pressure actually, but while the car's pressure switch was out, we flooded it with WD40/RP7/CRC lube spray, and it was caked with crap and rubbish.

Gave the mongrel a good clean, and after re-fitting it, the pressures have returned to 'normal' on the guage.

Oil currently in it is 10w-50 Mobil 1, and she drove up to and back from Brisbane without missing a beat. Also drove around in Stop/start traffic on NYE in the 39 degree temps (didn't like it, but survived).

Still keep a close eye on the guages, but hopefully all good now.

Being a GTR, I know one day the engine will let go, but the previous owner spend a good $12k on the engine prior to me getting my hands on it, so I am hoping it will last a little longer than a few months.

B.