Engine is a 3.8. My oil pressure gauge is suspect, IMO, as will show some pressure at start up and while going down the road at 3,000 RPM, but after being warmed up will drop to about 0 at idle. I think I remember reading that one can verify oil is being circulated by simply taking off the oil filler cap and just looking inside to see if oil is coming up to the cams. Is this a decent indication of lubrication system working ? I've also read that replacing the oil pressure relief valve and spring is a good thing to do - but again, don't know if that is an issue or simply an old , balky pressure gauge. This engine had been recently rebuilt ( less than 200 miles ago) under the PO's direction, so I really don't know much about that project. I've no reason to think anything is amiss as the engine sounds great, idles smooth and runs fine, although I'm still in the breaking in stage due to other numerous minor issues.
Schmitty

 

Most oil pressure "problems" are the gauge and sender. The senders are notoriously flaky. I'd verify the pressure with another gauge, preferably mechanical, before making any further steps.

But yes, observing the oil from the filler cap will tell you if you have oil getting to the top of the engine.

 

Faulty oil pressure senders are common. I have been through three in as many years. Same symptoms. One minute pressure steady at 40 psi them drops to nothing then back up to 100 psi. Checked inside the oil cap and oil is being thrown around all over the place so no lack of oil at the top end. No noises coming from the engine which is always a bad sign so I changed out the sender. Worked fine for a couple of months and then back to the same symptoms. I keep meaning to change the spring and valve as they are only £23 for the pair via SNG just a real pain of a job to do as access is so limited at that point especially the rubber return hose that goes between the sump and oil filter housing. https://www.sngbarratt.com/English/#...rnedDown=false
Easier with the carbs off but have no intention of going there for some time.

 

Everything JB and Cass have said. If you take the oil filler cap off, you don't exactly need or want to look inside. A serious cloud of oil mist will come out of a running engine or it always did from mine. It certainly shows their is some pressure there and that oil is circulating. Still, to be sure the pressure reaches the standard 40psi at 3,000rpm requires a mechanical gauge.

 

ya...i bought a new relief valve recently and intended on installing it immediately, but for some reason i'm finding other car projects, that prior to purchase of the valve and were of little importance, have now become critical.

 

See my thread: Fit a Bourdon tube pressure gauge even if temporarily. What viscosity oil are you using? BTW a SAE 5W-40 synthetic is fine unless you have a badly worn engine.

https://www.jaguarforums.com/forum/m...cation-209831/

 

I have fitted a mechanic's mechanical pressure gauge to my engine in anticipation of its first start up since a full rebuild. The most difficult part was finding an adaptor to go into the oil filter housing. There is a bunch of bad information out there regarding the thread on the pressure sender (and oil filter housing). It is a 1/4 BSP which means it is a British Standard straight pipe thread with 19 TPI. It is not a tapered pipe thread and it is not a 1/2-20 English/SAE thread. The seal is created by the copper washer, not pipe thread interference. I eventually found an adaptor on eBay that worked to adapt it to my general purpose oil pressure gauge.
Just wanted to pass that along so that you don't damage the filter housing or have oil spraying everywhere. On the plus side, if you do have oil spraying all over the engine bay, you likely have really good oil pressure!
I contacted SNG Barrett regarding an adaptor they sell and they told me it is a 1/2-20 SAE thread. Assuming the sales person was correct, it should not be used.
I learned more about pipe threads trying to figure this out than I really need to know.
Hope this helps.
Craig

 

We discussed some of this a year or so ago when Cass(?) was trying to fit a gauge. I think I suggested trying to tap into the oil gallery on the side of the block via the row of bolts (or set screws) that might well be 1/2inch UNF. I don't know how that went ...

 

Glyn, I'm running "break in" oil. Shell Rotella T1 SAE 30, which, according to the container meeets or exceeds API Service CF-2, CF, SL. also meets MTU A001061/35E. Whatever these means. Glyn, I'm sure you know. I'll change this oil before my next driving. I'll be away from the car for August , but back in September.
Schmitty

 

You Should really break in on SE or SF if you can find it. SL is too good & will retard break in. Can cause cylinder bore glazing & polishing (Two different mechanisms) and give you an oil burner for life. Don't pamper the engine during beak in & increase Jags recommended RPM by at least 1000rpm. Lubricants have come a long way since Jaguar built the car.

Craig (Jagboi) asked me to do this:

https://www.jaguarforums.com/forum/m...engine-263052/

 

For Schmitty. This is what I'm running in/breaking in on. Chevron appear not to sell it in the US. (Chevron, Texaco & Caltex are one and the same company now merged ~ One of the longest JV's in the world, Californian Standard Oil & Texas Oil Company hence [CALTEX] prior to merger in 2002 where I was sequestered at the Richmond refinery & living in Marin County on the FTC "Clean Team" for merger). Oilco's can waste money. They were paying for my apartment in Sydney Aus. & another one in Marin, 2 Cars etc.

You are going to have to search your oil shops and look for something similar from a reputable manufacturer. The US today carries a lot of the premium synthetics but you will find an SF. Your chances of finding an SE are close to zero. Available in SAE 30 & 40. Diesel performance is unimportant. They are rev limited by the combustion process and don't run aggressive cams.

 

Wouldn't most cheap oils with SF and lower from a motor factor or, if you want to be more up market, Castrol Classic XL be OK?