Oil change warning! Do not drain too long!

fishwenican
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Re: Oil change warning! Do not drain too long!

Unread post by fishwenican » August 17th, 2014, 5:55 pm

Dmax......u seem to know it all....
So if the pump is submerged then once the oil is drained and refilled it should be the same as before the drain.
Rhetorical question by the way.....
I havnt missed any points.....
How do you dmax manage to survive around us less genious ?

mydmax
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Re: Oil change warning! Do not drain too long!

Unread post by mydmax » August 17th, 2014, 6:10 pm

The thing is After a long drain sometimes it isn't all as it was before and there is the problem.
You do realize the pump is not like other vane pumps don't you. It is a variable output/displacement pump which maintains a set pressure and alters it's flow rate. ie varied for what is required. Why it is made so it can stop pumping is a good question.

Ps I do not know it all and never will!
It is nothing to do with geniuses or claiming to know more than you, I merely point out what is there and what happens as I understand it.

4wheeler
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Re: Oil change warning! Do not drain too long!

Unread post by 4wheeler » August 17th, 2014, 9:08 pm

For me any information is good. If people take the time to point out possible problems, good on them. Might be an oil pump problem, might be chassis cracks, might be dropping electric seats, who knows. Might be only a few vehicles, might be hundreds. However, if I can avert a possible problem (real or not) simply by not letting the oil drain too long, I'll take that any day. If in the long term it turns out the cause is something else not related to oil drain time, nothing lost.

Scotty_56
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Re: Oil change warning! Do not drain too long!

Unread post by Scotty_56 » August 18th, 2014, 7:50 pm

Agree 4wheeler, if the info is out there we can make a value judgement as to whether we want to take notice of it. :)

Itsbrung
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Re: Oil change warning! Do not drain too long!

Unread post by Itsbrung » August 26th, 2014, 5:47 pm

yep I think you got it, the pump will be belt, chain or cog driven, the more the engine revs the faster the pump spins the bigger the volume. If they are pressure fed then they have a "trigger" to control the flow.

mydmax
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Re: Oil change warning! Do not drain too long!

Unread post by mydmax » August 26th, 2014, 7:42 pm

Itsbrung
Some oil pumps are not belt chain or cog (as you put it) driven at all.
The BT50 oil pump IS chain driven with sprockets.

The faster the engine spins the faster the pump spins, true, BUT it does NOT mean more volume. It is not the same as what you consider normal. It maintains it's constant output no matter how hard you cane it. It only pumps enough to maintain a set, pre determined, oil pressure.

Gof
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Re: Oil change warning! Do not drain too long!

Unread post by Gof » August 27th, 2014, 2:58 pm

It is a vane pump with a moving outer body which changes the discharge/inlet port positions to control the pressure.
It rotates at (relatively) low speed so centrifugal force is not particularly high, unlike say an air grinder and as the outer body moves it leaks/has blow-by around the moving elements.
The vanes need the built up pressure from normal running to force them against the outer body to make a seal.
When it is full of air and is pushing up against a filter assembly also full of air this pressure can take a long time to occur, if at all.
To maintain the pump's charge of oil is relatively easy:-
1/ Drain the oil
2/Refill the sump
3/Change the oil filter
4/Start the motor.
That way it will seal enough to pull the small amount of air out of the pickup pipe and start running normally.

It is not a good idea to drain the oil for excessive periods even with a conventional gear oil pump as the motors initial dry running period before oil is delivered to the bearings is where 99% of engine wear occurs, check out the mileage taxi motors do, they rarely stop for any long period so the bearings always have oil in them.

axialmark
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Re: Oil change warning! Do not drain too long!

Unread post by axialmark » September 12th, 2014, 3:08 pm

After reading all of the above posts I spoke to the service manager where I purchased my BT 50 in 2012, he advised that there have been reports of this happening but he believes most are caused by home or fleet mechanics who probably drain the oil then go for an extended smoko break. So it does appear that leaving oil to drain too long may cause a problem. However most normal people drain the oil then refill as soon as oil has finished draining so in normal circumstances it should not be a problem. It is still good to be aware of the issue all the same.

hoyks
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Re: Oil change warning! Do not drain too long!

Unread post by hoyks » July 10th, 2016, 12:09 pm

I got this info from a bloke on another forum who got it from a bloke that actually services them for a living:
Maza Posted 08 July 2016 - 09:17 PM

Oil Change Technique

I have spoken to an ex-student who works at Mazda and services BT50's on a daily basis. His oil change technique is as follows-

you will need -13mm socket for the sump plug.

- 27mm socket for the oil filter casing

- 15mm socket to remove bash plate

- New fine Phillips head screw driver to remove scriverts in the wheel arch.

- Fine flat bladed screw driver to remove o-ring on filter case from it's groove.

- 8.8litres of Valvoline SynPower 5W-30 FE oil.


******Keep the time from dropping the oil to refilling and starting the motor to 10minutes to be on the safe side********


1- Turn steering full lock to the right.

2- With a new phillips head screwdriver undo the top 3 scriverts and fold down the inner guard behind the front passenger wheel

3- Undo the oil filter with a 27 mm socket until you can feel the rubber o-ring with your finger (so the last bit of thread is holding the casing). Lift the casing up and down to remove the air lock in the casing. This will stop you dumping a large amount of oil on your garage floor!!!

4- Undo the sump plug and drain the oil from the motor.

5- Completely remove the oil filter casing slowly.

6- Remove the filter. Make sure the filter has not left a small o-ring behind that was part of the original filter. Remove the old o-ring in the filter casing.

7- Put in the new filter and new lubricated o-ring in the filter housing. Tighten filter casing moderately, remember the o-ring is doing the sealing in a plastic canister.

8 - Put sump plug back in when there is only a fine stream of oil coming out.

9- Refill the motor with 8.8 litres of oil.

10- Start engine -oil pressure light should go out in 3-5 seconds

11- Refit inner guard.


****note - may need to replace o-ring seal on sump plug on some services. May be handy to get a few from Mazda in case it gets damaged. I doubt I could get to Mazda and back and stick to the 10 minute time frame for a service!!!

If the oil pump fails to prime they have an old oil filter plastic canister where they have drilled a hole in the end. They have screwed in a coupling to attach to a vacuum pump. Apply vacuum to housing until oil comes through. Start engine and hope oil light goes out.

He does the oil changes with a warm engine.

Hope this information helps - It worked for me!!!
http://www.ozmazda.com/board/index.php/ ... -32/page-3

So, there you go. Apparently the way to get the oil pump to prime is to suck the oil up into the pump vanes, a modified filter housing is the way they do it.

Billhacka
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Re: Oil change warning! Do not drain too long!

Unread post by Billhacka » December 28th, 2017, 1:47 pm

Guys, I had the oil pump issue whilst changing the oil on my 2013 XLT Ranger and followed the advice of the previous post. I got another oil filter cap from the wrecker's and drilled a hole to fit an air hose fitting. I then connected a suction hose to it and with the engine off, sucked the oil from the sump, thru the pick-up & pump, thru the filter & out the hose. I pulled about a litre of oil to make sure all the air was out and then started the motor. The oil light went off 2 seconds later! Job done. Thanks for the advice!

hoyks
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Re: Oil change warning! Do not drain too long!

Unread post by hoyks » December 28th, 2017, 3:29 pm

I'm glad it helped.
The site I pulled it from has had the plug pulled on it, so lucky that info wasn't lost with it.

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