Prefill Hydraulic filter, yay or nay??

[RickB]

Can you please explain why pre-filling a filter is a bad practice?

There are too many opportunities to introduce contaminants to the system that is to be protected. Remove the wrapper from the filter and install it, nothing simpler and easier.

 

[franklinute]

I do fill all vertical spin on filters as close to full as possible before installing. Usually fill close to full, let it settle then fill again. There are some vertical cannister filters with a removeable element that cannot be filled because the centerbolt used to tighten the cannister will leak unless tight.

 

[bindian]

I will prefill any filter that can be prefilled. It will get oil pressure to the working parts sooner.

In theory, yes. But you are just pumping up pressure the first few seconds. It helps a little.

You want a film of oil everywhere before draining the oil. This is why you are suppose to get the oil hot before changing.

It is the only way to be sure all parts are coated in oil on startup. But, if you take an hour to change your oil, all bets are off.
hugs, Brandi

 

[Soundguy]

oil film should stick around for a while unless washed off.. just think what your tractor does when you aren't driving it.

soundguy

 

[sweep]

oil film should stick around for a while unless washed off.. just think what your tractor does when you aren't driving it.

soundguy

Exactly..tractors that sit for 2 weeks or longer then get started up.

I drained my oil last night and when I went to put in one of the drain plugs found the special washer with the oil seal was shredded. Picked up a new one today and filled up with 9 gallons of oil tonight.

Started the tractor and let it idle for 30 seconds then shut it off. Put some more oil in and when turning the steering wheel the PSteering felt sluggish for 8-10 seconds or so then was fine.

I raised up the lift slowly 4-5 inches then put it down just to get the fluid flowing. Shut tractor off then checked the oil again-added a little bit and then started the tractor up again and moved it outside.

I really doubt I did my tractor any harm by letting it sit 24 hours without any oil. I doubt I di more harm by waiting 24 hours than guys who never change the oil at all in 10-15 years or longer and I bet I took more slow "break in" precautions than most techs do at NH dealers.

PS I never pre filled my filter. It never said to so so in the manual and the Messicks site has nothing about pre-filling either.

I also figure when those 9 gallons were going in there was oil going everywhere and coating much of the internal assemblies.

Did not hear any abnormal sounds or noises upon startup.

 

[sweep]

You want a film of oil everywhere before draining the oil. This is why you are suppose to get the oil hot before changing.

I always thought you got the oil at operating temp so it drains out more thoroughly???

 

[bindian]

I always thought you got the oil at operating temp so it drains out more thoroughly???

That also.
hugs, Brandi

 

[bindian]

oil film should stick around for a while unless washed off.. just think what your tractor does when you aren't driving it.

soundguy

With all the oil drained and sitting for a while, and no oil in the filter can cause problems. Normally when your engine has set a long while, there is oil in the filter. When the oil is drained and all residual oil has drained down into the pan, that thin film of oil left can get scorched or removed by movement before the oil filter fills and lubes the whole engine with a thick film of oil.

This is why new engines have to be prelubed by turning the oil pump with a shaft on a drill before first start up. So if you have have an empty oil filter.................and let the engine set for a long period, it can make it worse on start up.
hugs, Brandi

 

[Mace Canute]

When you think about it, there is really no valid reason that says you have to prefill any filter. Millions of vehicles and pieces of equipment have horizontally mounted filters and/or canister style filters and they all get installed without prefilling them with oil and without any ill effects.

RickB's admonition about possible contamination while filling them is a very valid point and care must be taken if you decide you prefer to prefill.

 

[Bigfoot62]

i usually prefill any filter that is vertical, and mounts with open face up. if vertical, and open face down.. nothing.

if horizontal, then i add 1/4 full.

oil pressure is max at cold start and running and primed. how would a filter burst from prefilling? it's made to take that max pressure an more. nothing magic happens to increase the pressure in a pre filled filter. any air in there is going to compress anyway, and any air int he system will be expelled and purged thru oil ports and clearances..

soundguy

+1 Me too. :thumbsup: