Maybe the pickup screen was gummed up and having the oil warm at startup helped the oil suspend the varnish. Now it flows better at all times.

If that is the case, maybe a couple of warmups like that before each oil change could be helpful.

In the meantime, it seems there is a in pan oil heater available. It is a straight heating element mounted on a 1/2 NPT bush that goes through the side of the oil pan. The cord attaches to the outside of the bush. You would have to remove and drill the oil pan. Search temro + oil on ebay ... about $35.

 

Be careful with oil heaters, the heating element should not go over a certain temperature as you could breakdown the oil, but I forgot what it was.

 

It's not a problem, especially given the large capacity of the typical Jaguar sump and the low wattage. The Temro in sump version is 300 watts at 120v. The 300 watts is constantly dissipated through the pan wall as well as into the block and coolant. After three hours it can be expected that the pan can still be comfortably touched with a bare hand.

The API measurement of operating temp viscosity is at 100*C, the HTHS at 150*C, and the typical flash point of conventional engine oil is over 200*C.

The oil heaters are not meant to get the oil even to operating temperature, only to get it warm enough to be usefully close to operating temperature rather than being a jelly.

 

True that, and today's 0W and 5W grade oils (as recommended in the owners manual) really don't need external help in staying thin enough for starting.

As why the OP's problem went away, I seriously doubt it had anything to do with the temporary addition of a heater. Applying 300 watts of heat to bottom of a V8 engine for one hour will make little appreciable difference in heating the oil. The heat is radiating to atmosphere almost as fast as it is being created.

Most block heaters up here are 800-900 watts and are used only when it actually gets cold, -20*C or less. My S-type came with a factory installed example, I never bother with it.

 

Well, I dont know about that.
But having a monster magnet on the oil pan can only be a good thing... I might just add a magnet... even though I do use the cylinder block heater.

Cheers!

 

You can buy a magnetic oil filter bandolier.

Or make one from six hard drive magnets placed between two layers of duct tape. Wrap it around your oil filter and move it when changing filters.

Some people also drop one in the power steering reservoir.

 

Drinking the Cool-Aid...

 

... and very tasty indeed!

 

Besides the block heater, I have also installed a 250 watt heater like below on the engine and gearbox oil pan:

Works very well.

 

Definitely the Hawthorn effect! Hawthorne effect - Wikipedia, the free encyclopedia

LOL

 

You'll have to find some other piece of dirt to fling.

The Hawthorne Effect speaks to the change in behaviour of live test subjects who know that they are under observation.

Both oil and ferrous particles are inanimate, unsentient objects.

Now if you are trying to state that engine oil and gear oil do not have an optimal operating temperature range that is above ambient, I suggest you do some reading of the technical literature, not internet "experts" ... or go post your claim at bobistheoilguy.com ... make sure you post it as an assertion of obvious fact .. they'll have a field day with you.

If that doesn't work at bobistheoilguy, you can always fall back to the position that oil and contaminants thereof are in fact animate, sentient beings subject to "The Hawthorne Effect".

LOL x 2

 

Why Plums, you take me for a Rational Person...! But how can a Rational Person love, own and be possessed by a Jaguar?

For me she's a Lady, with all the beauty and temper that comes with that.

We should grab a beer and explore our different planets one day!

lol x 3

 

Each to their own planet, mine shows Ladies more beautiful and interesting with warmingup ;-)

 

Because a rational person can also have a soul. Indeed, the rational side nurtures and accomodates the less rational side as being complementary to the rational.