Hi all,

This weekend I picked up a immaculate 85 sovereign. From what I gathered the car has not been started in 15 years and after flushing the fuel and changing the pump I got the car going with some good tlc. Problem is that occasionally when at idle the oil pressure gauge will drop away and the idiot light will start to flicker. The engine runs like a watch and has no bad noises at all even when the light is flickering. I have given it a dose of 20/50 and a new filter but the problem persists. Im assuming its probably a sticky oil pressure relief valve? with a slight increase in revs the pressure goes strait up, although it never gets past the '3' mark of the gauge, whereas my other xj6 idles at '3'. If it were the gauge alone I would not be too concerned but seeing as the light comes on too im a little worried. Its done 168,000 kms so im hoping if i put a few miles on it it will improve.

Any ones experience with this type of issue would be appreciated!

Thanks,

Jay

 

Very well could be the relief valve. Unscrew the big nut holding the relief spring in and check it out

 

Agreed on that valve. I have had that before and the gauge and light did exactly that. Found a small piece of gasket paper, NO IDEA, jammed in the valve.

A master mechanical guage screwed in the idiot light hole will give a definate answer.

Also check the wires just aft of that switch arrangement, from memory, haha, there is a metal loop that the loom passes thru, maybe after all these years it is rubbing?????

At 165000kms it is just run in, so I see no reason for the engine itself to be the issue.

 

Congrats on the purchase, sounds like a nice thing. I am envious at these oil pressure numbers, my lump would need to be doing 3000rpm to get near 3 bar on the guage.

You fleet must be growing, from memory you have a few cars.

 

+1 my series 3 has been throwing out low figures for the last 8 years! Still going strong though. Go figure?

 

After doing 300kms in the past few days the problem had not got any better so today I replaced the gauge sender with a new one with no improvement. i then tried a known good gauge, still to no avail. I then pulled the oil pressure relief valve off the car (the bolt on one on the filter housing) and inspected it, it appeared to be good so I stretched the spring a bit and put it back together. This resulted in slightly higher oil pressure at 3 grand but the same old issue at idle. As a last resort I went and bought some nulon 40-70 (one of the premium Australian brands) and dumped that in. Now at 3 grand the oil pressure is 1 bar higher now sitting around 4 but at idle it still drops away. When the engine is cold the oil pressure is around 3 on the gauge. I should note that idle is probably a tad low (550-600 rpm ide imagine) and as soon as you increase the revs a few hundred rpm it comes up to a reasonable pressure, but still a bit on the low side. The engine is as quite as anything and runs like a top whereas my other rattle old series 3 that probably has 300,000k's on it never gets anything under 3 on the gauge, even after driving on a 45 degree day.

So as far as I see it I have a few options:

1. Get a second hand oil filter housing with the bypass valve, oil pressure relief valve ect and change it over to see if this fixes it, although I think its a long shot.

2. Park it in the shed, pull the motor out and do rod, main and cam bearings along with oil pump

3. drive it and put some tape over the gauge and see how it goes, maybe put the idle up a little so it doesnt drop so low.

With 168,000 kms on it I honestly cant believe the bottom end would be shot but then again it may have been run dry on oil or anything in its life, who knows. I suppose there could be some sort of seal or gasket blown out somewhere inside the engine. Or maybe the pump pickup is sucking air or something? I cant imagine these engines would be too hard to work on and I would be confident doing the bearings myself. Head gasket would probably also be an idea while its out

Any suggestions / input / experience would be appreciated.

Thanks,

Jay

 

Hi Jay,
I would suggest the tape method. I have had close to 30 cars and 30 motorcycles. Only two have ever had an oil pressure gauge. The 95 Jeep I had for 17 years and the gauge was always 3 bar. The XJ6 where it is low. Read the thread below......

https://www.jaguarforums.com/forum/x...re-xj6-129789/

As Grant Francis would say....

 

If I had that decision to make, I would be sliding off to SuperCheap etc, and pick up a universal oil pressure gauge. You may have a dash unit that is not doing the right thing, and that is common to a point.

You are looking for a mechanical style gauge, with various adaptors in the packet.

Remove the idiot light switch, and screw this thing in, and see what it reads.

That will give you a much better idea of what is really going on.

The S3 did have some issues with main bearing "rumble" on the last of them, sometimes, but that is really audible, even to a novice, so I doubt you got that issue.

Excessive cam bearing bleed off can give what you got, but without knowing the actual pressure as I suggested above, it is still a guess.

Obviously, the engine may be really sad, as you suggested already.

 

Check this out Jay, but since you do work in a mechanical workshop so you should have one readily available.

13pcs Engine OIL Pressure Test Tester Tool KIT SET Diesel Petrol Gauge CAR Truck | eBay

 

Black Texta works also.

Suggestion #6, get a "pegged resistance" sender unit, later V12, and then the gauge will read a set number ALL the time. Just like a Coon, or DunnyDoor, or some Mitsushitties.

Anyway, ALL of this is invading "beer o'clock" HAHAHA.

Its an XK engine, solid as they come, and sooooo forgiving, sad to see them drop out of use.

 

Not in this house, I always have one eye open for a back up XK unit at the right price,

Love my straight 6's, had plenty of V8's,fast 4's etc. This is the second best "6" I have owned(after my Holden Red 186, 200k miles when I got it ,550k miles when I sold it) and only time it stopped was a loose LPG earth wire to the carby.

 

I must admit although I do work in a mechanics workshop I am probably better set up for most jobs at home then what they are at work, but thats another story..... I am constanly frustrated at work knowing if I were at home I would have the right tool or whatever to do the job, such as a 13 mm deep oddset ring spanner that i needed the other day...

Anyway back to the issue at hand, I have one of theose friends who has just about every pipe / electical / mechanical fitting and gizmo possible so ill drop down to his place and see what i can mock up in the way of a mechanical gauge but seeing as the idiot light flickers as well im quite worried.

I just took the car for a run to the petrol station and here is the exact behavior:

At 100kmh (2500 rpm) that gauge is sitting a whisker shy of 4 bar, at 1500 it drops back to about 3 bar and then at 1000 it slides progressively down towards 1.5 where it will hover while doing 600 rpm in gear hot. If you bring the idle up ever so slightly it will improve drastically so tomorrow I will probably put the idle up a bit to keep it happier. I have tried 2 separate senders and gauges and they both read exactly the same so im fairly sure they would be trustworthy but i will defiantly check it out with a gauge

The car drives soo well that I am really tempted to take it on the 300 km return trip im doing tomorrow but im hesitant with this oil pressure, its almost all freeway so there it would be sitting happy at 4 bar all the way but I dont want to get 150kms away from home with 5 people in the car and spin a big end or something so at the end of the day ill probably take the old dunga falcon with 300,000 on the clock. how worried would you guys be. I know it would probably do another 500,000 k's like this but should i test the theory?

thanks,
Jay

 

1. I hear you about the work tools. My 4 drawer kit at work has more than the company tools and the 7 other tradesmen combined.(and they wonder why I lock it?)

2. I ran mine to Armidale ,Goonadawindi, Brisbane circuit(1200+ km) with 0-20 psi oil pressure and nearly 0 engine temp. 80 mp/h most of the way. Was all good.
Drove to Ballina return, then Maleny return from Brisbane recently with near no oil pressure . All good.

Mechanical gauge is constantly running 50 psi when checked.

My theory is " If it sounds good, it probably is"...only for engines though, not advice!

 

Well, 1.5 is about 12psi, OK a tad worrying sort of, but not out of the ordinary.

The idiot light switch MAY be the wrong one. It is only an 1/8BSP with a spade connector, and some are set at 4psi, some at 7psi, some at 10psi, I WONDER. It is NOT a switch that is unigue to Jaguar, plain and simple. I also doubt it is the original, as they simply do not last that long on any car.

I ran a Toyota one in the HE coz the VDO that was in it leaked the other side of Dubbo YEARS ago, and that was all SuperCheap had with the same threads, and I have given it no more thought until now.

 

Grant, I think you were just lucky to just to find a parts store west of Dubbo.

 

Over the years I've known a number of cars that had virtually zero pressure at idle....even owned a couple of 'em myself. Years and tens-of-thousands of miles later they were still going strong.

A pal of mine has a Ser III XJ6. Bought it 12-13 years ago. I do a lot of repairs for him. Always had very low OP at idle. After a couple years of him calling me once a month for reassurance I told him to quit looking at the oil pressure gauge or I was gonna convert it to an 'idiot gauge' like Jaguar (and others) did on later cars!

I'll tell you what I told him a dozen times:

You can pull the engine for overhaul purely for the purpose of getting more oil pressure (that is, purely for the pupose of lessening your anxiety)

....OR live with the low OP at idle.

I know which choice I'd make!

Cheers
DD

 

I made a choice,....now.....what gauge should I put in that spot?

 

HA, as you do, and you know I do also, FORGET Jaguar when looking for bits, just find what fits and works, and get back to the beer.

I limped back to Dubbo, about 150KPH, saw SuperCheap in the side street, asked for a Falcon/Toyota/Mazda oil light switch. They all have a 1/8bsp thread. so done deal at $6.50, and changed it in the carpark, added 5 ltrs of oil, 15 minutes, off to the wild west and Darwin, good as.

I do have serious FAITH in all my Jags.

 

I just had a serious thought, scared the hell out me.

I GOT IT WRONG, BUGGA.

1 bar is approx 14psi, so at 1.5ish you have at hot idle gives ABOUT 20psi, WORRY NOT, start drinking, the Jag is all WARM AND FUZZY.

My sincere apologies for that major blunder.

 

Wow. I guess I oughta look into the Bar system of measurement??


Yeah, 20 PSI at idle is as good as it gets.


And, somewhere I read that for ordinary engines in ordinary driving, 10 PSI per 1000 RPM is fine.


My Jeep seems to use the modern, "don't worry" guage. Modualtedf to show about 50PSI always, no waver!!!


OTH, SBC's have always used relatively low OP. Mine lives just great at 40 PSI. Lower at idle, non modulated Jaguar system.


A few decades ago, my inquisitive son was messing with the very hotted up 312 Y block in his 40 coupe. On an oil flow and pressure kick. The original design oiling system not the best. The filter was remotely mounted. Whoah, revved it up and the thing blew the filter wide open. Oil all over the garage. Ugh, too much.


Carl