Oil pump (crankshaft front) oil seal failures

Everyone that has suffered the oil pump (sometimes called the crankshaft front) oil seal fail:

Has anyone had one fail on a new, or pretty new oil pump?

When yours failed, did you just renew the seal, and not the pump, only to have it fail again?

Those with modded pumps with an enlarged drain hole in front of the rotor, have you had a seal failure ever?

Excess crank end float was one thing I had in mind as a cause, but I have done some tests today on a bare crank and pump. If it had enough end float to be a problem it would have to gouge out the rear cover plate on the pmp before touching the seal, I'm sure it's not that. I have one here, in bits, the seal looked perfect until I carefully removed it. the tension circumference spring in the back of the seal had come off and was just sitting on the nose of the crank. It had lost a vast amount of oil, quite quickly. It even leaked at idle. The engine has no apparent crankcase pressure. I am now changing my opinion that crankcase pressure causes seal failure, and I am now thinking that worn pump rotors may be allowing more seepage into the front of the pump than the drain hole can cope with.

Very pleased that you have been doing a bit of digging into this problem Chris,

I have always thought that the US crank walk/end float theory was not correct for the reasons you have found, ( i presume you are referring to lateral movement?)

The one thing i am finding inconsistent is can a worn/or a pump worn enough to produce the leakage required to overcome the seal,and still produce enough oil pressure throughout the engine without showing detrimental effects or low oil pressure?

As you have probably read in my posts that i have very good oil pressure 25-35 psi hot idle and well over 90 psi from 3,000 RPM on, and only had the seal go on changing oil grade, and my engine only has in the 40K on it.

It would also be very interesting to find out about the results of enlarging the drain hole, i would have done this myself but for the fact that its a case of removing the engine or sub frame to get the pump off.

The one thing i am finding inconsistent is can a worn/or a pump worn enough to produce the leakage required to overcome the seal,and still produce enough oil pressure throughout the engine without showing detrimental effects or low oil pressure?

I was just wondering this too. Does anyone knoe what the oil pressure warning lamp is set at?

I guess you would need a to test a new pump and a worn pump back to back with a pressure gauge to know for sure.

Might help if someone with a recently rebuilt engine could post their oil pressure.

When people say "I have blown my FMS" or "My FMS has gone" what exactly has happened?

Do all the FMS failureslook the same - burnt out ID, seal out of position, broken or dislodged spring...does anyone know exactly what the failure is?

Does anyone have any "failed" FMS they could photograph please?

When people say "I have blown my FMS" or "My FMS has gone" what exactly has happened?

 

Do all the FMS failures look the same - burnt out ID, seal out of position, broken or dislodged spring...does anyone know exactly what the failure is?

 

Does anyone have any "failed" FMS they could photograph please?

Most of the time the seal will look no different from a new one, i think the few that actually get slightly pushed out of place (as Chris says they can't physically move much due to the crank trigger ring) they are more than likely due to being replaced already and fitted wrong.

The rest usually just get pushed out for a certain amount of time Will overcome by pressure, and will look no different,

I have an old seal but it requires damaging the seal in order to remove, so you cant tell.

Been doing a little more reading on the US " crank walk " theory, and it seems more plausible, as if the crank shims wear enough, it could then put pressure on the pump driven rotor and in turn wear the casing enough to allow oil past, but i have no idea if the crank drive splines for the oil pump as an interference fit or if the fir allows for the driven rotor to free float so as not to allow lateral force on the pump body which to me would make sense! Chris? Digsy?

They are usually free floating, and not that tight a fit, and two flats on the crank nose rather than splines - not sure of the 2JZ design though. Christ can confirm that having just pulled one apart

not sure of the 2JZ design though. Christ can confirm that having just pulled one apart

I'll just bag that for posterity, while failing to contribute at all to the thread.

Oh, has anyone got pictures of these components as I'm really not clued up on the oil pump design...

-Ian

I always do that!

The pump rotor floats freely on the splines of the crank. I can't see it being excessive end float, but I'll be measuring this on the engine that has had a seal failure, so i KNOW what the float is. Therr are enough urban myths about this.

Actually, it can't be excess crank pressure as short of dispacing the whole seal out of the pump housing, which is phsically impossible, excess pressure would INCREASE the lip pressure on the crank nose, not decrease it.

Can you get some photos up Chris(t)?

-Ian

Can anyone pull up some seal photos or photos of the embodiment please?

Even if the pressure seems to increase the sealing Chris the resulting loads on the elastomer could be too high and eventually fail the seal through excess friction, temperature, lubrication exclusion etc. I am not 100% familiar with the embodiment though so can't accurately contribute right now.

If I see some parts/photos/images/illustations etc I may be able to help - this kind of sealing scenario is relatively simple (although I'm by no means saying it's trivial) compared to some of the sealing designs I have been heavily involved in.

The pump rotor floats freely on the splines of the crank. I can't see it being excessive end float, but I'll be measuring this on the engine that has had a seal failure, so i KNOW what the float is. Therr are enough urban myths about this.

In that case the US crank walk theory can't be accurate, i was sure that Toyota wouldn't of been that lax in their design;)

There may be a lot of miss conceived information about, but as long as its considered and investigated, and learned from it all helps, you where previously adamant that crank seal failer was due to crank case pressure until recently, so it goes to show that we can all learn something.

It will be interesting to find out just what sort of end float you find.

In theory more pressure would result in a better seal, but there must be a point where the pressure must push the seal lips outward, maybe they cocked up on the seal specs?

I have been trying to think of a possible way that the drain hole could be enlarged in situe, but i'm not sure the risk is worth it, did wonder about taking off the lower sump pan and opening out the hole and flushing it through? i suppose another option would be an uprated seal??

dandan, i will post up a pic of my seal when i remove it tomorrow.

 

dandan, i will post up a pic of my seal when i remove it tomorrow.

Good man.

Anyone ever seen any crank wear where a failed seal was removed?

Anyone ever seen any crank wear where a failed seal was removed?

I mentioned it in the other thread. I've seen it a lot on test engines.

Any idea on the materials/seal compression/no. of rotations Digsy?

There's a lot to it as you probably know - some of the band aids I've seen like "shorten the spring by X%" can be a little bit gung ho and may not be the real answer.

Are you very familiar with the 2JZ setup and are your failed seals a similar design/embodiment to ours?

I had this problem on my car and it was because of an oil pump issue. The FMS should not leak at all if fitted correctly.

I had an issue on my car where the oil became contaminated with small metal fragments which went through the oil pump. This chewed up the pumps internals giving me a drop in oil pressure but the oil escaping from the pump built up behind the main seal causeing it to leak (badly).

Dropped all its oil on the road the first time so I tried all the tricks. Glue, Sealent and centre punching the oil pump caseing around the seal to hold it in but still leaked. In the end I pulled the engine and found the mangled pump and the metal in the engine. In the process of rebuilding it now.

Hope this helps

Lee

I was just wondering this too. Does anyone knoe what the oil pressure warning lamp is set at?

 

I guess you would need a to test a new pump and a worn pump back to back with a pressure gauge to know for sure.

Just to answer your question, when I had my problem I fitted a defi oil pressure gauge to check what was happening, when the oil was warm and I was slowing down and dipping the clutch the gauge would read 0 oil pressure for a second then go up to about .5 bar, and thats all I would get at idle. When on WOT I would still get 4 bar even with a mangled pump.

The stock Oil pressure light never came on even when the defi went to 0 and shouted at me.

Thats just rubbish!

Just to answer your question, when I had my problem I fitted a defi oil pressure gauge to check what was happening, when the oil was warm and I was slowing down and dipping the clutch the gauge would read 0 oil pressure for a second then go up to about .5 bar, and thats all I would get at idle. When on WOT I would still get 4 bar even with a mangled pump.

 

The stock Oil pressure light never came on even when the defi went to 0 and shouted at me.

 

Thats just rubbish!

Could that be down to the location of the Defi oil pressure sensor being a different place to stock sensor?

Surely at 0 oil pressure stock should warn unless open circuit in wirning sensor?

Any idea on the materials/seal compression/no. of rotations Digsy?

 

There's a lot to it as you probably know - some of the band aids I've seen like "shorten the spring by X%" can be a little bit gung ho and may not be the real answer.

 

Are you very familiar with the 2JZ setup and are your failed seals a similar design/embodiment to ours?

Just re-reading your post on the previous page and I'm not sure we are talking about the same thing. The wear I see on cranks is a groove all around the sealing surface. Its just a normal function of the rubber lip running on the metal - its not down to any particular type of overloading. This would be after about 600 hours of running.

It would be very unusual for the crank to walk to far forwards that the seal could get could get mangled or the pump could get axially loaded. Front crank seals aren't particularly hard to engineer and the duo-rotor oil pump dsign is as old as the hills. No way Toyota should have got any of that wrong.

I'm not familair with the 2JZ setup but I'm assuning that its a concentric duo-rotor with a the ports at the front (in the casting) and a flat or partially ported backplate. A graet many oil pumps are, although I personally prefer them to be in the oil pan but then you have to engineer a drive system too.

I've heard of oil seals popping out from excess oil leakage - otherwise why put the drain hole there - but I've never come across it for real. This could be the root cause, but like Chris I'd be surprised.

The wear I see on cranks is a groove all around the sealing surface. Its just a normal function of the rubber lip running on the metal

That's what I was getting at - same thing

Just re-reading your post on the previous page and I'm not sure we are talking about the same thing. The wear I see on cranks is a groove all around the sealing surface. Its just a normal function of the rubber lip running on the metal - its not down to any particular type of overloading. This would be after about 600 hours of running.

 

It would be very unusual for the crank to walk to far forwards that the seal could get could get mangled or the pump could get axially loaded. Front crank seals aren't particularly hard to engineer and the duo-rotor oil pump dsign is as old as the hills. No way Toyota should have got any of that wrong.

 

I'm not familair with the 2JZ setup but I'm assuning that its a concentric duo-rotor with a the ports at the front (in the casting) and a flat or partially ported backplate. A graet many oil pumps are, although I personally prefer them to be in the oil pan but then you have to engineer a drive system too.

 

I've heard of oil seals popping out from excess oil leakage - otherwise why put the drain hole there - but I've never come across it for real. This could be the root cause, but like Chris I'd be surprised.

Another of those 99% posts my friend

I'll strip a stock, no problem pump and see what it looks like, (the pump the relief valve springs came out of, a UK 120k miler engine) and measure clearances. if this engine with the seal problem gives further trouble with a new seal, and i get to strip it, I'll do the same again.

I find it odd a 300,000 miler car i still occassionally see has never had apump, nor popped a seal.

If the seal saw such pressure as to turn the inside lip inside out it would stay taht way. I would imagine a few hundred PSI woul b be needed to do this, and that isn't going to happen.

All I can see wrong with this seal is the tension spring is off. It's still supple, never leaked ubtil 2 days ago, and it SUDDENLY dumped virtually a full sump full of oil when the owner gave it a moderate amount of gas on a dual carriageway. Only his astuteness saved the engine. Afterwards, on tickover, it was still dumping a prodigious amount of oil past the "seal". There was no apparent blow by at the cap, PCV system, or empty dipstick tube.

If anyone has an oil pump from an engine that has blown its front seal, and since repaced it with a new one, I'd love to have a proper look at, and measure of the thing.

All I can see wrong with this seal is the tension spring is off. It's still supple, never leaked ubtil 2 days ago, and it SUDDENLY dumped virtually a full sump full of oil when the owner gave it a moderate amount of gas on a dual carriageway. Only his astuteness saved the engine. Afterwards, on tickover, it was still dumping a prodigious amount of oil past the "seal". There was no apparent blow by at the cap, PCV system, or empty dipstick tube.

Quick hand calcs:

Typical pump, say, 17cc/rev running at top engine speed and 80% efficiency.

3.4cc/rev leaks out of the rotors (worst case)

That's 22100cc/min or 0.37 litres per second

So in theory you could empty a 5 litre oil pan in just 13.5 seconds!

What I don't get about that is the fact that the front crank seal does not (or should not, at any rate) play a part in keeping pressurised oil inside the pump. That's the job of the rotor face clearance. Also, any oil leaking past the rotor face on the pressure side should in theory get sucked straight back into the suction side, then there's the drain hole for any excess that gets outside.

Maybe when you develop a rotor leak the time from leakage to the seal popping out is so short that you don’t notice the drop in pressure before you dump all your oil?