i've recently bought a '96 v8/3.9 litre petrol disco. i'm about to do my first oil change, and the LR workshop manual says "caution: v8 petrol engines. the engine oil filter must not be removed whilst the sump is empty, otherwise the oil pump may have to be primed." can anyone shed some light on this? i'd like to think the shop manual knows better than me (i'm no mechanic), but i don't fancy the oil shower that will most likely occur if i remove the filter before i drain the oil (and i don't imagine priming the oil pump would be an easy task either). thanks for any input.
changing my engine oil filter
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discool
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I've done V8 oil changes a few times now and never had any probs. I alway fill the the new filter with some oil before fitting but thats it.
Or if you wish drain the sump first and refill and then do the filter. Sump oil won't drain past the pump or if it did it would only be a drip.
Or if you wish drain the sump first and refill and then do the filter. Sump oil won't drain past the pump or if it did it would only be a drip.
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Thats a good practice, also allow it to idle until the oil light goes out and a few light revs to check for oil leaks.
When we did the high performance cars we also imobilized the ignitions and spun them over until the oil lights went out, then started them.
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It's not a big deal to change the filter before draining the oil, as the filter is full of oil whatever the state of the sump oil level.
What the manual is saying, and I can confirm this, is that if the oil filter is taken off with the sump empty, all the pressure side of the oil system will empty into the sump as air is let in at the filter gasket area.
That means that it takes much longer to fill the galleries and oilways on restarting. When we rebuilt our V8, it took ages for the oil pressure to come up, partly because the air 'in front' of the pump just compressed and coulden't get out anywhere.
Easier to change the filter (fill slowly with new oil so the filter is full up) and then do the rest of the oil change after the filter is refitted.
Peter
What the manual is saying, and I can confirm this, is that if the oil filter is taken off with the sump empty, all the pressure side of the oil system will empty into the sump as air is let in at the filter gasket area.
That means that it takes much longer to fill the galleries and oilways on restarting. When we rebuilt our V8, it took ages for the oil pressure to come up, partly because the air 'in front' of the pump just compressed and coulden't get out anywhere.
Easier to change the filter (fill slowly with new oil so the filter is full up) and then do the rest of the oil change after the filter is refitted.
Peter
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