changing oil on V8 what is the correct way? (and what is overdoing it)

[prelude]

Gents,

Having read the thread recently of a 3.9 that wouldn't build pressure, I was reminded about the (in my opinion) finicky nature of changing the oil on my 4.6 GEMS. I heard about the pump being difficult to prime before and indeed mine was packed after the rebuild to facilitate that. This makes me wonder though.

Thus far I have pre filled my new oil filter with new oil to the brim and set it aside. Drained the oil from the sump and lastly removed the old filter, which is always a hassle since the steering arm is in the way, splattering oil everywhere in the hurry to get that thing out in stead of just letting it drain for a while before removing and then with my slippery as **** hands grabbing the new filter and trying to get it into place ASAP with the risk of dirt and sand getting in there. Usually I need to clean everything twice and re torque the oil filter at a later stage.

Since I always do my oil changes myself this is... workable I guess but there will be times that I can not do it myself whilst on the road and I am at the mercy of mechanics that hopefully know what engine this is and how it needs to be treated.

So, am I overdoing it or is a 10 minute oil filter change (with an empty filter) actually not a problem. ie. can I rest safely when some mechanic deep in the jungles of the congo whose language I barely speak changes the oil?

Cheers,
-P

[101RRS]

I have never had an issue changing the oil filter on a 3.5, 3.9 or 4.6 as part of a standard oil change - unscrew and just screw in the new one.

[ozscott]

They self prime quickly. Run motor to get oil hottish. Just drop the filter off and drain plug in whatever order you fancy, then let drain being careful not to burn yourself. I sometimes let it drain for hours if not in a hurry. Tiny film of clean grease or fresh oil on the rubber filter seal. Then stick plug back in and prime filter by part filling allowing for angle it goes on at, filter on. Hand tighten. Start engine. Oil pressure up quite quickly. Fast idle is best for quick pressure build but generally I just let it idle. Cheers

[loanrangie]

It's only if you have the engine apart (timing cover off) that you will have problems priming the pump.

[101RRS]

My 101 with its 3.5 had been parked up for over 10 years. Unlike other engines that mostly have oil filters pointing down the 101 has a filter that points up so over time oil drains out.

When I started the 101 first time I did not then know about the priming issue and just went ahead and filled with new oil, and new filter (noting it cannot be prefilled) and when it finally fired up I had oil pressure straight away no issues.

My 4.6 on rebuild, self primed after about 15 secs of the engine firing up.

[prelude]

So I overdid it :) I plan on putting a proper oil pressure gauge in so I can actually see what it is doing in stead of relying on just the on board light so that should give me more peace of mind.

Thanks for all the experiences guys!

-P

[101RRS]

A oil pressure light will give a much earlier indication that you have oil pressure than a gauge will.

[loanrangie]

A oil pressure light will give a much earlier indication that you have oil pressure than a gauge will.Most pressure gauges are electric and use a similar switch so not really.

[Pedro_The_Swift]

X2 for a light.. a gauge might be a bit scary when the oil is old and hot.... [bigwhistle]

[Homestar]

X2 for a light.. a gauge might be a bit scary when the oil is old and hot.... [bigwhistle]

The light can be too - the old 3.5 in the Rangie used to have a flickering low oil pressure light on a hot day when at the traffic lights - no gauge so could only guess how low it was getting but never had an issue.

To the OP's question - I did once have the 3.5 in my 101 not prime after sitting over covid. Took 10 minutes to pull it off and stick a handful of Vaseline in it to get it to do so.

[Tombie]

Heck, I'd drop the plug - go have a coffee and lunch and then wander down, spin off the old filter, spin on the new, fit sump plug and casually fill it back up.

Never a worry

[prelude]

I was not planning on removing the light itself, just add a gauge. Not sure how long it would take me to get the cover off though, the serpentine GEMS takes a bit more work I guess but it should be all good. I reckon the car won't stand still for THAT long.

-P

[101RRS]

You dont need to take the cover off - just unscrew the oil light sender from the side of the oil pump (above the oil filter) and screw in a Y piece or something similar - screw in the oil light sender into the Y piece and screw in the oil gauge sender - all done.

[prelude]

Any chance you know the thread size ;) Then I can simply order a Y piece without taking it apart first.

Thanks!
-P

[101RRS]

Sorry no idea - you do need to do some measuring first to get a connector that has the right thread and will fit in the area.

[AK83]

Any chance you know the thread size ;) Then I can simply order a Y piece without taking it apart first.

Thanks!
-P

From what I can find, it's 1/2" UNF parallel thread.

very early(as in 99 model D2's) seem to use the same part, IRRC that you have a P38 RR. STC4104

easy to find adapter would be a 1/2" t adapter, where most seem to have a 1/8NPT side thread.
That is, fit the adapter to the original oil warning light thread, then fit the oil warning light to the 1/2" female port, and find a 1/8 NPT sender for the additional sensor.

as an example of an adapter: (https://www.merlinmotorsport.co.uk/p/oil-pressure-gauge-t-piece-1-2unf-tp-1-2unf)

I've done this to my tdi, where I have both oil temp and pressure sender, as well as the original warning light sender too .. ie. I've used 2 t piece adapters to have all 3 sensors connected.
One tip on this(what I found) ... don't use gaskets/sealing rings. I've tried them all, rubber/fibre/copper ... for some reason they don't work well. sealing ring worked fine on the std oil warning light sender, just not so good when all sensors were fitted.
Thread sealant fixed all of that up tho, and a bucket load easier to install too .. no fiddling with gasket rings in tight spots then fitting sensors, where two hands may be needed but only a one finger can fit ... kind'a thing.

I was going to recommend to install the additional sensors onto the adapter, then fit the adapter, but this looks painful on the RV8 in this era .. it appears that there's no room for this to work. In fact there doesn't look like much room for the adapter to fit into that space where the oil pressure light switch is fitted.

[prelude]

I might have to crawl underneath to see whats what then. I seem to recall there are products that screw in between the oil filter and the housing, usually for turbo's and what not, that can be used to fit sensors. Might give that a google.

Thanks!
-P