Lazy Oil Pump

[DoseVader]

Hi Everyone,

I was told on my last tune that my oil pump was starting to get a bit lazy at idle, its fine when it's got some revs behind it. What are my options here, I was told to try run a thicker oil or is it worth investing in a genuine/aftermarket oil pump? What are some good oil pumps to suit an RB25DET NEO?

Current car stats: 1998 R34 GTT 300hp on 13psi

[Ben C34]

Thicker oil.

What gauge were they using? I hope not the stock one.

Its not particularly easy to replace the pump, so I would be trying thicker oil first.

[DoseVader]

I will drop the oil and try a thicker one.
Not sure but I doubt it was the stock one as every one knows they arn't accurate.

[Ben C34]

Also it tends to be the engine worn out dripping pressure rather than the pump went out.

[DoseVader]

Yeah makes sense the car has 160 thousand on it so its expected. I got a new highflow going into the car in a few weeks and the boost will be turned upto 18psi so will just keep driving it till it dies.

[jjman]

Thicker oil.

What gauge were they using? I hope not the stock one.

Also it tends to be the engine worn out dripping pressure rather than the pump went out.

this and this.

but also, have you had the motor compression/leakdown tested? If the motor is too tired putting a highflow on it and upping the power a lot when the motor is potentially really tired will just result in a dead motor eventually (and poor results from the modifications).

[DoseVader]

wouldn't hurt to do a leakdown test in the future but right now for the mods the car has its making the right amount of power so I am not to concerened about the engine being really tied. My guess is I need to run a thicker oil as I gets thiner as it heats up.

[jjman]

For sure. what oil do you have in it currently?

a 40w oil is generally best for the RB25 with a few k's on it.

[DoseVader]

I wouldn't know as it was done on the last service but will keep the oil you susgested in mind when I change it soon thanks for your help

Edited February 25, 2015 by DoseVader

[MrStabby]

Thicker oil.

What gauge were they using? I hope not the stock one.

Its not particularly easy to replace the pump, so I would be trying thicker oil first.

100% right.

DoseV, since you dont know what oil is in there now, contact the shop that did the service to find out what they use. If that doesn't work just get an average price dino first while you're trialling viscosities to see what works. Maybe assume they used a ?w-40 and try a ?w-50 first.

Once you've settled on a viscosity that works, step up to a good full synth and go the full 5000kms change interval.

[GTRPSI]

So what oil pressure readings are you getting to call low?

10PSI for every 1000 RPM is all you ever need......

If your seeing 60 PSI or over at 6000, your good for 6000RPM, over 30 PSI at 3000, and so on.

Dont trust the factory oil pressure senders, make sure its aftermarket and post your results at each 1000 RPM.

Usually its worn bearings rather than worn oil pump giving the low readings unless your pumps bypass valve is stuck open or the pumps seriously worn and damaged.

A thicker oil will mask the issue.

[jjman]

100% right.

DoseV, since you dont know what oil is in there now, contact the shop that did the service to find out what they use. If that doesn't work just get an average price dino first while you're trialling viscosities to see what works. Maybe assume they used a ?w-40 and try a ?w-50 first.

Once you've settled on a viscosity that works, step up to a good full synth and go the full 5000kms change interval.

id assume any shop would do the easiest thing and just read the manual and put in the factory rec of 30w.

[Ben C34]

I'm struggling to believe a tuner bothered hooking up an accurate gauge onto your engine.

Can you confirm with them how they can to the conclusion of lowish pressure?

[DoseVader]

I'm struggling to believe a tuner bothered hooking up an accurate gauge onto your engine.

Can you confirm with them how they can to the conclusion of lowish pressure?

I doubt they did as well my guess is the oil in it now is way to thin thus making the engine a bit noisy once the oil is warm at idle. But any way the car is going for a retune and full inspection in 2 weeks.