oil pressure sender

Talk about the E-Type Series 2
User avatar

Topic author
M4rk
Posts: 45
Joined: Mon Oct 13, 2014 11:02 am
Great Britain

#1 oil pressure sender

Post by M4rk » Thu Sep 17, 2020 2:49 pm

Hi All,

I'm after a little advice, I have a 1970 series 2 and replaced the Oil Pressure sender unit because my existing one became intermittent, I purchased the unit listed for my car on a well known supplier website, the new sender reads off the scale on my gauge (over 60psi) the supplier has replaced the unit but the replacement still has the same problem? All parts on the car are original so not sure what the issue is.
The supplier is not sure, so I wondered if anyone has had the same problem and how it was resolved.

Thanks in advance for any help

Mark
1970 Series 2 fhc E Type

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 6068
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#2 Re: oil pressure sender

Post by mgcjag » Thu Sep 17, 2020 3:02 pm

Hi Mark.....if you have a wireing fault and the wire from the sender to guage is earthed then you will get a full scale deflection on the guage.....or if you have a faulty guage.....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
M4rk
Posts: 45
Joined: Mon Oct 13, 2014 11:02 am
Great Britain

#3 Re: oil pressure sender

Post by M4rk » Fri Sep 18, 2020 11:02 am

Hi Steve,

Thanks for the reply, nothing has been changed just the sender, the original sender was reading fine when it worked!
1970 Series 2 fhc E Type

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 6068
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#4 Re: oil pressure sender

Post by mgcjag » Fri Sep 18, 2020 11:10 am

Hi Mark....as far as i can tell from your post your old setup developed a fault......this could have been the guage/sender or wireing. ....but you have now replaced the sender twice and still have a fault......you say that the original sender " was reading fine when it worked"....how do you know its a faulty sender....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
M4rk
Posts: 45
Joined: Mon Oct 13, 2014 11:02 am
Great Britain

#5 Re: oil pressure sender

Post by M4rk » Fri Sep 18, 2020 12:18 pm

Hi Steve,

The old sender on occasion used to drop to zero on the gauge, rather frightening when on a long journey and then after a while or next journey would work as normal?
1970 Series 2 fhc E Type

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 6068
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#6 Re: oil pressure sender

Post by mgcjag » Fri Sep 18, 2020 1:11 pm

Sorry to repeat myself Mark......but how do you know it was the sender that was faulty....what did you do to prove it wasnt the guage or wireing....I am only trying to help...but maybee time for someone else to take over....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

JerryL770
Posts: 380
Joined: Sat Dec 09, 2017 2:58 pm
Location: Northants
Great Britain

#7 Re: oil pressure sender

Post by JerryL770 » Sun Sep 20, 2020 11:30 am

With the electric oil and water temperature gauges (both work the same way), the gauge is between the power supply and the "sender". The sender is acting as a variable resistance to earth.

The gauge works by the resulting current, which increases as the pressure/temperature increases, heating a bi-metal strip more, which moves the needle more. If you have a short circuit inside the gauge going straight to earth after the heater, through the gauge case, the needle goes full scale.

Guess how I know this :doh:
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

MikeMilton
Posts: 36
Joined: Thu Nov 29, 2018 5:08 pm
Location: Gooderham, Ontario
Contact:
Canada

#8 Re: oil pressure sender

Post by MikeMilton » Sun Sep 20, 2020 12:39 pm

The other thing to check (probably the first thing to check upon gauge problems) is the voltage regulator for the gauges. They function at 10V (not 12) and the regulator is just a bimetallic set of points that opens and closes so that the average over time should be 10V. The gauges are damped such that you don’t see this intermittency.

If the read off scale (high) it is quite possible that the regulator is stuck closed.

You can buy a replacement but the best / cheapest approach is to replace the ‘guts’ of the regulator with a TI UA7810CKCS IC which can be had for about $2. The data sheet for the chip shows the (very simple) circuit requirements.
Just an old guy living by a lake - with a 1969 E-Type FHC, and 1962 OTS
Image

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 6068
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#9 Re: oil pressure sender

Post by mgcjag » Sun Sep 20, 2020 12:59 pm

Hi Mike...the oil guage does not use the regulated voltage....only the temp and fuel guage use it....Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

ALAN COCHRANE
Posts: 637
Joined: Sun May 06, 2012 9:37 am
Location: Fife
Great Britain

#10 Re: oil pressure sender

Post by ALAN COCHRANE » Thu Sep 24, 2020 7:38 am

Hi Mark

I think we can safely say you’ve eliminated the sender as a suspect. Three units later and you’re still having problems with the gauge reading accurately and consistently.
It sounds like you’ve had an intermittent short which has now become permanent. A very common route for an electrical fault to take.
You’re next move would be to run a temporary live feed from the battery- inline fuse included of course. Then if the fault persists run a new wire between the gauge and sender. This will then reveal if it’s the gauge or a section of the wiring.
Your then only left with the gauge I’m afraid.
A general rule in fault finding is to check the least cost option and work from there.
Alan Cochrane

1962 S1 OTS,1968 Triumph TR250, 1971 Triumph GT6 Mk3, 2008 Porsche Boxster RS60 Spyder

Link:
BBcode:
HTML:
Hide post links
Show post links


SimonBrown
Posts: 63
Joined: Sun Dec 04, 2016 9:15 pm
Location: Solihull
Great Britain

#11 Re: oil pressure sender

Post by SimonBrown » Thu Sep 24, 2020 6:57 pm

Hi Mark,
Have you checked the oil pressure with a mechanical gauge. My 1970 S2 OTS, with the original electrical set up reads over 60psi when cold and even hot at idle only drops to 45 -50psi.
I have checked with a mechanical gauge and results are pretty much the same.
Could this be why XJ6 gauges were changed to read up to 80psi in 1971?
Unless your gauge reads off the scale all of the time it might be correct, and you just have good oil pressure
Regards
Simon
Simon Brown
S2 OTS

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

chrisfell
Posts: 1251
Joined: Tue Oct 06, 2009 9:52 am
Location: Salisbury
St Lucia

#12 Re: oil pressure sender

Post by chrisfell » Fri Sep 25, 2020 7:46 am

Many years ago, at a JDC event, a S2 owner was worried that his oil pressure have fallen to zero as he drove onto the site. He started the engine, it sounded good - no rattles from dry big ends. He took off the oil filler cap to see the exhaust cam swimming in oil at tickover. The engine had good oil pressure, but a bad sender/gauge. In those days (probably around 2005) I went through four senders in quick succession. Since then one sender has worked sufficiently and consistently well for me to be happy checking it as I drive.

It isn’t always the sender, though. Another owner suffered a loss of pressure after a long motorway drive, only to discover that the pressure relief bypass hose had perished. The engine had dumped over a gallon of oil on the M1.
Chris '67 S1 2+2

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
M4rk
Posts: 45
Joined: Mon Oct 13, 2014 11:02 am
Great Britain

#13 Re: oil pressure sender

Post by M4rk » Wed Sep 30, 2020 3:13 pm

Thanks for all your posts, It looks like I have some further checking to do next chance I get.

I had seen lots of comments about faulty Senders hence the choice, I should know better to check everything myself before buying parts. The gauge reading does drop a little once engine is fully up to temperature so I think a pressure test is the first job, then a look at the electrickery.

I will report back with results

Thanks
Mark
1970 Series 2 fhc E Type

Link:
BBcode:
HTML:
Hide post links
Show post links


SimonBrown
Posts: 63
Joined: Sun Dec 04, 2016 9:15 pm
Location: Solihull
Great Britain

#14 Re: oil pressure sender

Post by SimonBrown » Wed Sep 30, 2020 5:18 pm

Hi Mark,
When you have done your mechanical pressure test would you be kind enough to let me know the results?
There appear to be mixed feelings about correct oil pressure on these Series 2’s.
My car shows 60 psi plus when cold, only dropping a little when idling hot. My engine builder assured me it just has good oil pressure. Also it never goes over 70 psi when cold, indicating the pressure relief valve is working correctly.
As I said in my previous post this could be why Jaguar changed to a 0-80psi gauge for 1971 XJ6.
Look forward to your results
Regards
Simon
Simon Brown
S2 OTS

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

malcolm
Posts: 1950
Joined: Fri Jan 03, 2014 10:44 am
Location: Fleet
Great Britain

#15 Re: oil pressure sender

Post by malcolm » Thu Oct 01, 2020 8:58 am

My 4.2 goes to 70 when cold, and when hot runs at 60+ at revs above 2500.
On really hot tickover, it drops to 30.
These were measure by a garage with a professional oil guage strapped to the door, with tubes leading under the bonnet. I then had a mechanical guage (0-100)fitted and get exactly the same readings.
Malcolm
I only fit in a 2+2, so got one!
1969 Series 2 2+2
2009 Jaguar XF-S
2015 F Type V6 S

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Adamski
Posts: 76
Joined: Sat Jan 07, 2017 2:36 pm
Location: London UK
Great Britain

#16 Re: oil pressure sender

Post by Adamski » Tue Oct 13, 2020 9:18 pm

On my S3 I am working on a plan to have two gauges,one mechanical. Fed up with that sender that I've replaced at least 3 times,deep down under.Mind you first one lasted over 30 years no doubt Smiths and not China. Worldwide shortage of senders C31177. Details to follow based on tip here on Merlin Motorsport.
Adam
S3 V12 E Type FHC Manual 1972-owned since 1978
1957 XK150 since 1976

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Adamski
Posts: 76
Joined: Sat Jan 07, 2017 2:36 pm
Location: London UK
Great Britain

#17 Re: oil pressure sender

Post by Adamski » Sun Dec 06, 2020 11:07 pm

I have fitted a new sender and manual gauge now. Tough job on the early V12. I now find the original gauge reads about 10psi more that the manual.My pressures are good at about 40-50 psi when in motion. I am pleased I've done the job but I will be reverting back to 20 50 mineral oil in the future. I have the best Castrol Edge at present but feel these engines need a good slurry.
Adam
S3 V12 E Type FHC Manual 1972-owned since 1978
1957 XK150 since 1976

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Topic author
M4rk
Posts: 45
Joined: Mon Oct 13, 2014 11:02 am
Great Britain

#18 Re: oil pressure sender

Post by M4rk » Fri Jan 08, 2021 6:33 pm

Hi All,

Sorry it's taken so long to get back, after a pressure test I found I have similar pressures to Simon, 60+ when cold and drops to 55 ish when hot.
The engine has only done about 5000 miles since rebuild, hopefully I'll get some long runs in when the weather improves to ensure it is stable.
1970 Series 2 fhc E Type

Link:
BBcode:
HTML:
Hide post links
Show post links


SimonBrown
Posts: 63
Joined: Sun Dec 04, 2016 9:15 pm
Location: Solihull
Great Britain

#19 Re: oil pressure sender

Post by SimonBrown » Sat Jan 09, 2021 4:52 pm

Thanks Mark,
It does appear these later XK engines run with higher oil pressure than earlier cars.
I can see no other reason for Jaguar changing the gauge on 1971 XJ6 cars to read to 80PSI.
However I cannot find any engine changes listed that would support this theory.
Mine does not drop below 50 PSI even when thoroughly hot and idling.
Simon
Simon Brown
S2 OTS

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Fuel.inj
Posts: 46
Joined: Sat Oct 03, 2020 12:26 pm
Location: Monmouthshire
Wales

#20 Re: oil pressure sender

Post by Fuel.inj » Sat Jan 09, 2021 7:32 pm

I read with interest these posts and others on this forum regarding oil pressure senders and gauges. I am of the old fashioned mechanical bias and have been contemplating replacing my electrical setup with a capillary system. My S2 on a fairly low mileage engine shows about 45-50 when cold and then drops back a little.
I note that MC Wilkinson sell a kit but shows it only with a braided hose and some owners recommend nylon.Are there any other suppliers members may know of these days.
Paul.
Paul.
1971 S2 FHC (Opalescent Blue)
2007 Land Rover Defender
A number of Nortons.
1939 Triumph T100

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic