Hi guys,

My oil pressure is all over the shop! I've gone through a lot of old posts, but are the guages that inacurate!

The cars only used at w/e's - start up approx = 70 psi, 5 min later barley 30 psi.

And if I stop in traffic 0 psi.Accelerate back up to 60 psi!!! the lumps only done 25500 miles (new engine fitted in sep 99) Is this due to oil deteriation or gauge in pissed mode. Very worrying at lights etc.

Advice please.

cheers

harve.

 

Freaky... I was just about to post this exact message =)

 

Harve, my gauge behaves almost identically to yours, with the addition that it falls almost to zero after a few minutes of gentle driving. But give the accelerator a bit more exercise and up it goes...

 

My engine's done around 45k; the temperature never deviates from the norm. I'd be interested in any replies too!

 

Raz

 

Hi guys.

I think you'll find that's whats supposed to happen. 200's are the same.

As far as I'm aware it's due to the fact that at low temps (first start-up) the oil is thicker and therefore the pressure greater. Once it warms up to normal operating temp the pressure drops to about 30 psi. Increases to about 70ish as you give it a bootful etc.

Drops off again after.

 

200's do this. Probably the same for 300's I expect.

 

Matt

 

Same with mine - around 75 stone cold and 50 @3000rpm+ warm, 15 - 20 idling. 25 - 30 puttling around at 30mph 1300rpm. My 240Z was the same a way back. You get a new Nissan electric sender and it shoots up to where it should be. The electrical sender wears out inside I think and becomes inaccurate in the zones where it usually moves around. Mine was replaced 20k ago so they dont seem to last that long either. Open the filler plug when hot idling and you should see a well wetted cam lobe spinning around - at least that shows lube at the top end at hot idle when pressure is lowest.

 

I had the same oil pressure issue.

Sure it can be a pressure sender that has gone senile, but before you replace it, I'd try different oil first.

Castrol RS 10W60 fixed it for me.

Oil-pressure is now pretty stable and the lowest I've had it is 15PSI at idle after VERY hard drive..it used to be 0 PSI with other oils (Magnatec and Valvoline)

Also it is ESSENTIAL that you use a genuine Nissan oilfilter, since those cheap orange ones you can get at halfords,etc are the biggest crap you can find !

Something else that might help is cleaning the connector on the pressure sender.

 

-Eric

 

I read on TT.net that the wires that go into the electric connector to the sender can be too short and the heat off the engine can cause problems with the reading, take the connector off, clean it up and refix longer wires. I keep meaning to try it coz my oil is all over the place, I'm going to do something at my oil change, I may take the old one out and clean it through and see how that goes too! Buying a new one is my last option!

 

I also was worried by the same symptoms, even though the oil pressure was between the normal working range indicated in the owners manual. This weekend I fitted a new Nissan filter, changed the oil to Mobil 1 15/50 from Mobil 1 0/40 and connected up my Autometer oil pressure gauge. The results are exactly the same but now I can witness it down to the last psi! I don't worry about it too much since the engine has survived many excursions into the 120 mph zone and a few times into the 140+!

 

Jim G

 

I had this exact problem when i first got my Z.

 

i went through a few oil changes with different oils, all with the same symptoms.

 

Changed the oil pressure sender unit, and hey presto, all problems gone.

 

starts at 90psi, runs 60psi until warm or under accel, goes to 30psi at idle, dips to 20 or so after long hot run....

 

change the sender, easy to do at oil change time

 

Guys,

 

Those of you that have them, check in your manual, I had this with my Supra Turbo. Shit myself big time when I saw that I had virtually no oil pressure at idle once warmed up to normal running. But when I checked in the handbook it shows the correct limits for your oil pressure gauge.

 

So when I got my 300 that was the first thing I checked, at idle under normal temperature conditions you should have virtually nothing reading on the gauge. Again, this will be slightly different for those of you using thin oils like Mobil or Castrol RS etc.

 

Provided that you are seeing pressure when you accelerate don't worry too much as low oil pressure when driving is a concern.

 

But if you're still not happy with this get your oil pressure sender checked. Amazing what you can find out when you read the manual from cover to cover. I also found out that Supra engines are designed to burn oil and that this is nothing to worry about. Now if I hadn't had the manual I would have immediately thought that something was not right...a little knowledge is a dangerous thing?

 

Later

 

Tim

;-)

 

 

Thanks everyone,

off to buy oil, filter, and sender.

 

cheers

 

harve.

 

I think these readings are quite normal for cars of this performance and pressured engines. My dad has a 1 of 6 in the country Lorinser Mercedes 500sec and his oil pressure guage responds almost exactly the same as mine and all of yours, although his does have a 5.5l v8 lump in it. mmmmm

 

Dan

 

Took Z to Nissan MK yesterday, they checked engine oil pres' and sender. They said its all 100% This is suppose to be like this!

All diognostics also 100%. But it just looks worrying."What did I expect from a 10 year old super car".

All this was also free & curtious, they must be aware of the other forums on this site!