The 'E' Type Forum

My V12 e type always shows 80psi on start up and falls to 50 - 60- when warm and cruising, and 20psi when warm and idling. Oil pressure light goes out in 1 second upon starting

I just started the car and the oil pressure went to 60psi and then fell to 40 and then down to 10'ish but the oil pressure light went out as usual and did not come back on.

I immediately switched off and am now hoping for a fault in the gauge / sender ... oil level is correct and was changed 1,000 miles ago.

Has anyone experienced a similar (somewhat nerve-wracking) event?

I did on my series 2. It was the sender gone kaput.

Having changed the sender several times, I finally converted to a mechanical gauge
https://www.merlinmotorsport.co.uk/p/sm ... auge-cb-op
also see elsewhere on the forum. I changed over the facia to keep the correct looks, but then you have to convert values once to know actual pressure

Yup......got to switch to a mechanical Smiths gauge . Spot on accurate, very easy to install. FYI..rule off thumb in most engines, once oil is at operating temperature, expect 10 lbs of pressure for every 1000 rpm's. Pressure around 10 at idle, cruising around 3000 rpm......30 lbs of pressure. Light should never come on......its set for 5 lbs.

John

Not knowing that these oil pressure sensors "always" break, I ordered a new one from SNG about 7 years ago and it's still working and showing what I believe is correct OP.
Based on various posters concern about the reliability, I installed a mechanical OP gauge in the engine bay as a back up.
Until now they have both indicated the same pressure under same conditions.

My original electric sender worked for a while, as yours did, or still does. I believe this puts you in the "very lucky & blessed" category ! LOL I would still suggest , however, that a mechanical Smiths gauge ( looks like original) mounted in the dash, is the long term best way to go. Dead accurate, far more reliable then electric sending unit, and ultimately, greater piece of mind for the owner/driver as you observe conditions while driving. One man's opinion.

Happy motoring !

John

Hi,where is the best place to connect the pipework ,and do you have to drill and tap the engine block?

Why would you tap into block ??? Oh my.....a bit drastic. Simply switch to a Smiths mechanical gauge, as I described in an earlier post. Simple, and remember, once up to operating temperature, 10lbs of pressure for every 1000 rpm's. No more, no less. Happy motoring.

John

OK,where would you connect the oil pressure pipe tp the engine ?

Hi...driver...whats your name....please try to put it with your car model in the signature area..thanks....if you want to fit a mechanical guage you can remove the electric sender and refit a pipe for a mechanical guage you may need fittings/adaptors to make it all fit correctly depending on what you use... Steve

Hi Rob Gill here,
that is what i thought,but the photo on the topic looks like the connection has been made at the top of the engine block.
Thanks for the confirmation.

Interestingly enough, there is always alot of chat concerning Series 3 oil pressure gauge/sender/voltage regulator issues and how these components are known to be erratic or just not reliable.
I too have had problems with oil pressure / gauge readings with a '74 series 3 V12 OTS with less than 30,000 miles. Considerably nail biting when the gauge in one moment is reading circa 60psi and then drops to 20psi when driving at a consistent speed / revs. I have changed the sender and the voltage regulator twice and still the problem persists. I decided to bite the bullet and purchased a new pressure control valve (PCV) from SNG Barretts. A while ago a friendly and very knowledgeable mechanic said to me don't always assume its always down to the electrical components that are at fault. But until a week ago I had assumed this, having read many blogs that assumed the same. Well I removed the old PCV and immediately noticed that the piston in the old one was seized mid point whereas the piston the new one was fully extended to the end. On starting the engine, at cold 80psi and nearly 90psi!! and at warm 60-75psi never going below 40psi at low revs. Hopefully this fix lasts!!!!

Hello: As I have in the past, I would suggest a Smiths mechanical gauge for spot on, accurate readings. Once engine oil warmed up, rule of thumb, unless you have added some high performance racing pump (totally unnecessary ), oil gauge should indicate 10lbs of pressure for every 1000 rpm. I have a 5 speed, and cruising along at 75 mph, for example, turning 2300 rpm, my gauge indicates just shy of 25 lbs. No way your engine is producing 40 lbs plus. Im guessing an original electric sensor, and gauge, feeding you a false sense of security. Get the Smiths. Easy to install, and you can drive with the security that you know exactly whats going on under the hood. One other point....I have seen several owners mount a mechanical gauge under the hood,.... why in heavens name would you do that?? Totally useless when driving. Get the Smiths set-up and mount in the dash...looks just like the original. Happy motoring !!

John
1973 Jaguar V-12 OTS since new.

Hi rob Gill here,

Im in the process of doing just,
but thanks for the confirmation.

Is this another case of someone posting a question, their first and only post, and not bothering to read the responses or say thank you?