5W30

I've been losing sleep over my hot idle oil pressure. Just about 1 bar. It's been doing my head in :roll: even though I'm not getting any low pressure warnings. And then today, looking up the last service (done by previous owner) I just about made out a scrawl of 5W30 on the mechanics notes. On a 3.4 with 107k miles. :wack: The service was done only a few months ago but this oil needs to come out pronto! I'm juggling between 5W40 or going the whole hog , Millers CFS 10W50. Thoughts? Also, any guesses as to the sort of hot idle oil pressure increases I'd expect using the above oils?

Your oil pressure is fine. I used 5w/50 and mine sits at a bugs dick over 1 bar,stinking hot after I've just kicked its head in. :thumb:

Ballcock, I switched to the Millers 10-50nano. Hartech advise using a thicker oil as does the guy Raby in the USA that is one of the PCAs (Porsche club America) go-to guys as he is one of the main 996 and 997 engine rebuilders. I wouldn't rely on the pressure gauge. Both the senders and the gauges can be inaccurate. If you are in the PCI, there is a club sponsor that supply Miller at very good proces

Thanks Ghia, YHM. Personally I'd like to see more than a bar hot idle. Bearings are soft on these!

I've hovered between 0.8-1 bar for 5 years now and the car's up at 132k with no engine work.

That's interesting Alex thanks, I thought the standard was 1.5 to 2. It was on my last 996. I've seen quite a few posts on here stating 1bar is worryingly low.

2.0 - 2.5 bar in the main on mine in cold weather conditions. 1.0 bar when I've absolutely spanked it in hot weather Above 1 bar - generally closer to two in cooler conditions.

Thanks, that's what I remember from my last one. What oil are you using? Mine goes to one bar pretty much after 20 minutes of normal motorway driving. Mid winter. I should add that I've had the sender replaced, and the gauge seems to be working normally. 4.5 bar when cold idle, And even when hot it will go to 2.0 bar once the revs go a smidge above 1000. I've cleaned the throttle body, thinking the idle revs a are bit low (about 650 when hot). No change. I'm very hopeful fresh oil of the correct viscosity will make the difference.

10w-50 Millers all day long.

Millers CFS 10w50 Nano (that's due for a change)

1 bar is fine .. if you want a totally accurate measurement then you need to fit an external gauge and check it . If you have a flickering oil light then its time to worry ... never seen it though in 15 years ... in fact i dont remember a low oil pressure fault on Any Porsche in that time ... well not totally true .. some of the 1970 cars suffer a bit on idle .. never a problem though . 0/30 ?? really ? only time we use that is on diesels ! 5/40 is the oil we would use and obviously there are many people that choose different oils but anything from 0/40 and up is fine . 0/40 and thats what an OPC would use fyi .

As always thanks DM for your professional input. Yeah, re the 5W30, I've no idea what that lad was smokin. @Chris and TCF, thanks guys, Millers CFS 10W50 has been ordered. Oil change late next week when I'm back in town.

Another sufferer of pressure gauge paranoia here. :grin: My car used to sit at 1bar hot idle. 1.2 bar after moving to Millers 10/50. Even then it would be 1 bar after say leaving the car running throughout an mot, and revving it to get the emissions to drop into spec. I had my Indy use his mechanical gauge at my last service. My dash gauge is upto 0.3 bar out at various different temps and revs. I had my oil analysis done and all good so I just need to get over it. I'm usually running 10/50 Millers, although currently I'm on my Indys Porsche spec stuff (so a 40 grade) after my top end work. I'll be switching back to Millers by the summer. I think 2 bar+ is very high at hot idle. If mine were that high I'd be wanting it checked for accuracy too. Turn your ignition on but don't start the engine. If the needle goes to anything over "0" the sender's probably faulty. Edited to add. My car had a bit of a rough idle when really hot, causing the revs to hunt and drop etc. We've just fixed that so that has also helped my pressure. I'm now never below 1.2 bar even on the 40 grade. 1.4 usually, again at idle after a good spanking.

Thanks Marky, can you give some more detail on the work done to cure the hot idle roughness? Also, and I should have mentioned earlier, when I switch my air con on I do NOT get the few hundred rpm increase that some mention here, so I can't use this to increase idle and therefore the oil pressure. Interestingly the aircon does work, difficult to assess during cooler months but it clears condensation very quickly once on ....

I had some Millers 10w50 put in my car for its last service. I was skeptical, but I'm surprised by the difference its made to the car. Quieter on start up, particularly after a week or so of not being used.