My 92 V12 XJS can sit for weeks at a time without me starting it and I was wondering if there is a recommended additive I should add to the oil for upper cylinder lub to reduce wear. Any advise would be appreciated.

 

There's little difference in the amount of residual oil on critical surfaces after years of sitting as compared to hours. No additives are required or of benefit.

 

I agree with Mikey but if I have left a vehicle idle for weeks I pull the HT lead from the coil and turn the motor over with the starter motor , for a few seconds , which will pump oil around with no load then leave it for a short while to let the fuel evaporate and then start up.

 

+1.

Never used them, and I see them all as "snake oil" and the money at the time was better used on JD.

 

Todays modern motor oils are so good that I do not believe that adding any additional additive will help at all. I have used many oils and have stored a lot of collector cars and I stopped using additives a few years ago. I went with Maxlife 10W40 for my oil change last Fall and last week my 90 XJS V12 started up smooth as silk...

 

The above practice is doing more harm than good.

There is sufficient residual oil already on surfaces to accommodate a start up. By cranking the engine without firing it up, the cylinders are now flooded with fuel. This fuel will dilute the oil on the cylinder walls.

 

Yeah, I got away from Snake oil decades ago. Modern oils are just fine. Only caveat is the Zinc lessening, and it's consequences on some engines.


But, an oddity recently came to my attention. My daughter's gal pal has a circa 94 Cadillac Catera. In real life a German Opel. A very decent car, 154,000 miles not withstanding!!


On a trip to an oil change emporium, the low OP light came on. Yowee, off to her Cadillac client tech. Wrong oil. Viscosity rating not to spec. Swapped in proper viscosity and "motor Honey"! OP now fine. In my mind, proper viscosity, fine. Super
surprise that a CAD oriented tech would even contemplate "Motor Honey". Trade name remains anonymous for legal reasons.


My 94 vintage engines thrive on CarQuest house brand, aka Valvoline 20/50. Higher viscosity than factory spec. But, I am cynical as to the low viscosity stuff.
Objective in their case, better gas miles at the expense of engine longivity.


Side bar. Old Jeep purrs again. Fueling issue and guage issue resolved. Driving so much different than the lumped Jaguar. Each to it's own way....


Carl

 

Sorry Mikey , do not agree with your statement that " it will do more harm than good ". I will stick to my method.

 

everyone is entitled to their own choice, but not their own facts. You should do whatever you want. If you really are interested in protecting your motor at startup an oil accumulator would be the solution. They maintain oil under pressure and deliver it if you have any temporary drop in oil pressure. They can be manually released for oiling prior to startup.

 

Of course everyone is free to do what they want with their own car, that's never a point of debate. Making suggestions as to what others should do is slightly different.

What is being discussed is whether any extraordinary measures are required when starting an engine that's been at rest for an extended period. The key word is 'required'.

If it can be demonstrated that there is sufficient oil distributed throughout the engine at time of start up, irrespective of the length of storage, then no additional steps are required.

My background is in aviation with one of big 3 engine OEMs. I had the opportunity to witness the teardown of countless engines that, for one reason or another, not been operated for several weeks, months or even years. Quite often, there was also a request to test run one of these stored engines prior to teardown to confirm an issue, so the need to determine any potential 'requirement' for pre-oiling the engine was investigated.

It was determined quite quickly that an engine that had been stopped for weeks, months or years had the same volume of oil distributed on critical surfaces as an engine that has been stopped for just a few hours.

There is no 'requirement' therefore to pre-oil an engine before start up nor any need for snake oil.

The poster above who was cranking the engine without ignition is running the risk of flooding the engine with gas and thereby contaminating the oil, so this practice is potentially harmful.

If we really want to get technical, it can be demonstrated that cranking the engine without it firing up may not develop sufficient oil flow (pressure) to fully protect plain bearings, like the crank and connecting rods. The thought that there is no load on an engine during cranking is incorrect. The air in the cylinders is still being compressed if the spark plugs are in place, so the engine is not much different than a 12 cylinder shop air compressor.

 

I'm going with adding nothing. I use Castrol 20W-50 on the recommendation of my local Euro car guy and it's all good. I just thought it worthwhile asking is all.

In an old Silverado with 160k miles I tried all kinds of additives to stop or quieten the lifter noise on start up. Nothing worked so I got rid of it.

Thanks for the input.

Stephen

 

Slightly off topic but GM hydraulic lifters can 'leak down' while the engine is at rest. It's usually due to mechanical wear and no additive or super thick oil will make any difference. No actual damage is being done if they pump back up promptly after engine start. I usually just turn up the radio till the noise goes away.