Thread: food for thought - 5W-30 vis 5W-40 engine oil

Originally Posted by DiscoJeffster

I have a new pump and new bearings from 40k ago. I wonder what mine would be like

I'd like to know.. I'm thinking sump off and a bearing roll

Originally Posted by josh.huber

Where did you get that spec from Brad, the manual I have says over 15psi at all revs and under 65psi. Which annoyed me as it didn't specify temps or anything else.

Your source at least has rpm.

I was under the belief that piston squirts and turbos all shared the same supply as the bearings without valves.

2.7 TDV6 Workshop Manual Section 303-01C -> "303 Engine/303-01C Engine - 2.7L V6 - TdV6/A-Specifications/"

Screenshot_2022-04-24_17-22-40.jpg

Old manual, old engine, old spec. Dated 2009, so probably out of date.

Cmon man, your post had put me at ease, i was like ohh its not so bad, ill check the Cat Oil on cold startup tomorrow for fun, then check it again at 100 degrees, honesty the whole world ran 15-40 for so long, if i dont make the right pressure with it, ill have to just pull the diff and sump and do a roll and may as well chuck a pump at it while im there

Originally Posted by josh.huber

Cmon man, your post had put me at ease, i was like ohh its not so bad, ill check the Cat Oil on cold startup tomorrow for fun, then check it again at 100 degrees, honesty the whole world ran 15-40 for so long, if i dont make the right pressure with it, ill have to just pull the diff and sump and do a roll and may as well chuck a pump at it while im there

I was always told that plain bearings practically sucked the oil from the galleries, so as long as there is :
a) enough oil pressure to replenish that; and
b) enough oil flow to prevent it cooking

then it was ok. When you look at the bearing surfaces, crank, 4 cams and then the 6 cooling jets + turbos it's going to have to move a lot of oil to keep significant pressure. I'm sure the specs haven't changed much from the 2.7 to the 3.

The only other motors I've encountered with piston cooling jets (petrol or diesel) have had pressure control valves, so they only squirt when there's enough oil pressure precisely because they flow a lot of oil. I'm looking at a Volvo Penta manual now where the piston squirters don't open until somewhere between 12-17 psi, but the hot idle oil pressure is still specced at 21psi.

my laptop went flat today and ive had a chance after dinner to have a decent read just now, the specs are in the manual.

mine is considered normal, so thats a plus, ill still monitor the cat oil, but im thinking after all of todays thoughts that HPR5 might be ok for my worn out engine, i would like more then 10 psi at idle but LR says its fine so thatll do me.

what a roller coaster of emotions oil has become

Originally Posted by BradC

I was always told that plain bearings practically sucked the oil from the galleries, so as long as there is :
a) enough oil pressure to replenish that; and
b) enough oil flow to prevent it cooking

then it was ok. When you look at the bearing surfaces, crank, 4 cams and then the 6 cooling jets + turbos it's going to have to move a lot of oil to keep significant pressure. I'm sure the specs haven't changed much from the 2.7 to the 3.

The only other motors I've encountered with piston cooling jets (petrol or diesel) have had pressure control valves, so they only squirt when there's enough oil pressure precisely because they flow a lot of oil. I'm looking at a Volvo Penta manual now where the piston squirters don't open until somewhere between 12-17 psi, but the hot idle oil pressure is still specced at 21psi.

Yeah thats true, but the pump should be big enough to maintain enough pressure aswell, it's pressure that keeps the plain bearings off the crank. I guess that's why I'm paranoid. Because I've read a few people whose engines went bang at the lights. I was worried about low rpm pressure.

The valves are a good idea, you don't need piston cooling at idle, wonder if it's a horsepower save too?

Originally Posted by BradC

I'm sure the specs haven't changed much from the 2.7 to the 3.

Depends on what you class as ‘much’.

Details from the 3.0ltr T/SDV6 LR workshop manual.

It gets bloody hot around here, and 5w-30 does the job just fine running for hours on end.

I run Vantage 5W-30 in both our later LRs and the HPR Diesel 5 in the TD5 and won’t change.