Low oil pressure

[V8S]

Hi all,

I embarked on a trip a couple of weeks ago but was foiled by low oil pressure readings when at low revs.

I've done a search on here for tips but found little in the way of concrete advice of what to check first and how to do it in layman's terms.

I was getting readings up to halfway on the gauge at > 2000 revs but as soon as I changed up a gear, the reading would plunge to almost zero. There is definitely enough oil in the engine. Usually the gauge reads from quarter to half depending on revs.

Now, I'm hoping that it's the gauge or sender up the duff but I haven't a clue how to practically test these and I don't want to start the engine and do any damage.

Is this a job best left in the hands of Dulford et al? Having had the engine rebuilt in March - June and enjoying flawless running since then, I'm keeping my fingers crossed this is a sensor issue and not a mechanical one.

If anyone can give me a list of things to look at and how to do it, I'd very rather grateful. I'm tempted just to send it off to Dulford though but I MUST stop being so lazy!

ETA: Using Mobil 1 Motorsport 15/50 oil.

Edited by V8S on Wednesday 13th December 11:43

[garfys v8s]

graham give richard a ring. i recently had the same problem and all i needed to do was drain oil, clean out the sump, flush and refill. it is much better now but i am going to get an oil cooler fitted as well. gary

[Pies]

Isn't mobile 1 too thin for the V8, I've always been advised too use something thicker

[seb400]

Don't forget to check the oil pressure relief valve which can be activated and cause low oil pressure readings.

Steve

[V8S]

Pies said:

Isn't mobile 1 too thin for the V8, I've always been advised too use something thicker

I thought Mobil 1 was the manufacturer recommended oil? And I've read of several people on here with V8s who use it. I'm quite prepared to change oil cos it's expensive bloody stuff!

I guess I need to talk to Opie Oil Man or read the whole oil thread...

[V8S]

seb400 said:

Don't forget to check the oil pressure relief valve which can be activated and cause low oil pressure readings.

Steve

How?

I keep forgetting to look at the Bible - I'm sure it must say in there somewhere...

[nawarne]

V8S said:

seb400 said:

Don't forget to check the oil pressure relief valve which can be activated and cause low oil pressure readings.

Steve

How?

I keep forgetting to look at the Bible - I'm sure it must say in there somewhere...

Just be aware that the gauge can read low (or high!!). I had a similar problem after my upgrade by TVR Power...They put a (calibrated) wet line gauge on and this showed my dash to be reading about 10/12 psi low.

The oil pressure relief valve is in the housing that the filter screws onto. A 'smart' tap with a hammer can often reset the spring and put the valve back to normal....rather than wide open.
Nick

[veg]

Same thing happened to me as I trundled back from Le Mans one year. It is almost certainly the sender unit for the gauge. They are cheapish and easy to change but beware the replacemnts suffer from poor quality and could do the same.

If the pressure was too low the yellow low oil light would come on.

[the gazman]

Pies said:

Isn't mobile 1 too thin for the V8, I've always been advised too use something thicker

15/50 should be fine I would have thought, it's the poor deluded souls who use the 0/40 Mobil 1 in a 1950's RV8 who come unstuck IMHO, I have seen a couple of cranks out of cars who used it and they weren't a pretty sight.

[S2 Giles]

in laymans terms

Use Mobil 1 motorsport rather than plain Mobil 1
Or i have switched to Castrol GTX Magnetec, a fair bit cheaper and considering i change oil about every 5000 miles, it is excellent.

I can do around 3-4000 miles and the oil is still clear, it goes blacker after 4000 and i start thinking about changing it.