Jump to content
The mkiv Supra Owners Club

Oil leak after BPU


Fulcrum2000
 Share

Recommended Posts

  • Replies 127
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Having gone though this and doing a lot of research i would if i where you replace the oil pump NOW!

The front main seal failing is pretty much always due to the oil pump having too much clearance which allows too much oil to go through the bypass.drain hole this then builds up behind the FMS and causes it to fail from the pressure, the hole in the pump body can be opened up to help with this as done with the PHR and Titan pumps from the states.

 

This will help, but once the pump reaches a certain wear limit even that wont stop the seal from failing, and the pump will not show ANY signs of lower pressure either.

Believe me i have been there twice and got the T shirt, mine first failed when i went BPU, i then renewed the seal and it just happened again, so after some further research i then learnt my lesson and fitted a new modified oil pump along with super bright oil level warning light as if the seal fails big time it can dump the content of the sump pretty quickly, i was lucky and caught it in time.

 

 

Here is a link to one of my original posts on the subject, cant find the others, but here is another link to one that CW started and contains a lot of relevant info, unfortunately due to Photo buckets fook up most of the pics are missing.

 

http://www.mkivsupra.net/vbb/showthread.php?113789-My-Oil-pump-(crankshaft-front)-oil-seal-failure-Update&highlight=Oil+pump

 

http://www.mkivsupra.net/vbb/showthread.php?108524-Oil-pump-(crankshaft-front)-oil-seal-failures/page9

Edited by Tricky-Ricky (see edit history)
Link to comment
Share on other sites

I'm going to have to give it one try on the seal to see if the pump is fine as my current mechanic is well aware of what the oil pump change entails and as a BMW specialist (my other car is a 535D) he says its not something he wants to do so it will be a case of finding someone in Lincolnshire or the area willing to do it. Hopefully the seal will be fine and was 25 years old after all. As all the other seals were changed and this was just missed due to me not doing enough research beforehand on the stem seals it was the only old seal in there and hopefully just the weakest link in the chain.

 

Its been a nightmare year for me and my Supe, been in the garage for over 10 weeks out of this year so far with upgrades and repairs! Argh! But, when you stand outside of the garage bonnet up with your car pissing oil and waiting for the turbo timer to cut it out and a little boy comes up to you and says 'that is one heck of a nice looking car' it all seems worth it somehow.....

Link to comment
Share on other sites

Sorry fella but you have been warned, so keep a very close eye on you oil level light as if it happens again and you dont notice you will be looking for a replacement engine, mine only had 50K on it when the pump caused the seal to fail.

 

The job is not such a big deal if done on a lift, you just drop the front sub-frame to get enough clearance to remove the sump and then removing the pump is easy.

Link to comment
Share on other sites

Yes kind of a fait accompli anyway as its in his garage in pieces and would have to be a trailer job to move elsewhere for a pump. Worth a couple of hundred quid of labour hopefully sorting it and if not I guess its one of those things.

 

Just out of interest I've heard form a couple of people who had the seal go and then had to do the pump, are there people out there who had this leak, replaced the seal and it was fine after without the pump needing to be done?

Link to comment
Share on other sites

Just out of interest I've heard form a couple of people who had the seal go and then had to do the pump, are there people out there who had this leak, replaced the seal and it was fine after without the pump needing to be done?

 

As stated a few have only replaced seal to find pump needed doing. There is a knock on effect of only replacing a single component, naturally the weakest one will fail and potentially cause new parts to fail.

 

Just get the pump done mate and then you can at least sleep easy knowing it's a safer bet.

 

 

Link to comment
Share on other sites

Glad you found the issue mate.

 

I would recommend changing the whole pump tbh as others have said as a worn pump is normally the cause and as yours is one of the first models it is probably time.

 

Some do it with Engine our but you can drop the subframe and do it with engine in ( As I did). Any decent mechanic should be able to do it although the labour charge may be a bit intense.

 

Toyota still do the pumps I think. When fitting the seal donr push all the way back or else it will block the drain hole. Plenty of threads on here about fitting.

Link to comment
Share on other sites

Ok the only thing I don't get about this is it's happened straight after BPU (and valve stem seals?) now are we saying some debris from the seals has got into the sump and worn the oil pump a bit more to cause the issue?

 

What I'm getting at is the bpu aspect doesn't really affect what the pump sees does it? it'll accelerate that bit quicker but if the oil wasn't passing enough oil to cause an issue pre bpu why was it after? (assuming no extra damage)

 

What I am getting at is, is no blow by/boost/breather issue relevant in this (any?) case (I've no idea just speculating/questioning).

Link to comment
Share on other sites

This is what baffles me Scooter. I had no oil warnings, the car has only done 85k despite its age not 135k+ like most Supes. And it had valve seal issues since I bought it and smoked on startup. Do you think its more likely that fixing the valve seals at BPU simply removed an easy 'pressure release' for the oil and then the only old seal remaining (the FMS) blew, all of which would indicate an oil pump which wasnt in fact faulty, and if anything in fine condition to produce all this pressure? I'm talking out of my hat here (I often do) but that makes more sense than going bpu to only just under 1 bar and the oil pump suddenly going pop and attacking the FMS within 50 miles surely? And also wont an oil pressure test at various loads when rebuilt confirm the pumps health in situ?

Link to comment
Share on other sites

Ok the only thing I don't get about this is it's happened straight after BPU (and valve stem seals?) now are we saying some debris from the seals has got into the sump and worn the oil pump a bit more to cause the issue?

 

What I'm getting at is the bpu aspect doesn't really affect what the pump sees does it? it'll accelerate that bit quicker but if the oil wasn't passing enough oil to cause an issue pre bpu why was it after? (assuming no extra damage)

 

What I am getting at is, is no blow by/boost/breather issue relevant in this (any?) case (I've no idea just speculating/questioning).

 

For some reason it seems to manifest after BPU, and no there is no reason other than maybe people seem to give the engine a little more beans once BPU and perhaps some more RPM than usual which results in the oil pump pushing a little more pressure than is usual therefore creating more oil bypass from the rotors of the pump and in turn more oil in the gallery before the FMS... that's my take on it.

 

As for all the other crankcase pressure scenarios, i have yet to see one proved, unlike the reason for my FMS failure, to add to this i also tested my engine for any crankcase pressure both with the std and modified breather systems, by fitting a low pressure peak hold gauge to the dip stick tube and monitoring and at no time did it ever record any positive pressure, in fact the was minor negative which proves the PCV system works, and proves that FMS failure is not down to crankcase pressurization as many US bods think.

 

As i said before, the pump can have considerable wear and show no sign of loosing pressure, and pump wear is not always mileage dependent, because the ECUs run injectors at 100% during high boost and WOT the oil can get diluted with fuel, and this coupled with maybe not great oil maintenance can accelerate oil pump rotor wear, as i said mine was a fresh import with only 50K so it very difficult to tell the state of the oil pump.

Edited by Tricky-Ricky (see edit history)
Link to comment
Share on other sites

This is what baffles me Scooter. I had no oil warnings, the car has only done 85k despite its age not 135k+ like most Supes. And it had valve seal issues since I bought it and smoked on startup. Do you think its more likely that fixing the valve seals at BPU simply removed an easy 'pressure release' for the oil and then the only old seal remaining (the FMS) blew, all of which would indicate an oil pump which wasnt in fact faulty, and if anything in fine condition to produce all this pressure? I'm talking out of my hat here (I often do) but that makes more sense than going bpu to only just under 1 bar and the oil pump suddenly going pop and attacking the FMS within 50 miles surely? And also wont an oil pressure test at various loads when rebuilt confirm the pumps health in situ?

 

That's the same mistake most make as its an easy assumption, and as i have already said i have proved that its the pump that's responsible, also consider this, the only connection to the seal has to the crankcase and therefor any pressure is a tiny 3mm hole that the oil pump bypass is supposed to flow through, so transferring enough pressure through that to force out the FMS would need to be quite considerable as opposed to hydraulic pressure from the oil build up.

Link to comment
Share on other sites

Excuse my ignorance but what is WOT? Also lets say somehow I can convince my mechanic to fit an oil pump what kind of outlay is that financially. Hey I know its cheaper than an engine if it were the issue but has anyone had one done at a mechanic and what kind of spicy meatball pricetag does it come with?

Link to comment
Share on other sites

Do you think its more likely that fixing the valve seals at BPU simply removed an easy 'pressure release' for the oil and then the only old seal remaining (the FMS) blew, all of which would indicate an oil pump which wasnt in fact faulty, and if anything in fine condition to produce all this pressure?

 

I don't think it's this as the seals I believe are splashed with oil not part of the pressurised oil system.

 

It probably is as Ricky has described. You can envisage that the increase in acceleration from BPU means a significant increase in the number of revs in a certain time period, so more oil bypassing in the same time, which may tip the drain hole over the edge?

 

It would be very interesting to have a car like yours fitted with a new seal and then viewed from a rolling road at idle and then at x y z revs. If the worn pump and drain hole issue is the cause as suspected it shouldn't leak at idle or any gradual acceleration or even 3500 rpm steady state? (it must have seen that pre bpu?)

 

One of my cars has a weeping seal, it has had for some time, I have replaced the seal but didn't press it in as people say more fingers then a gentle tapping to attempt to get it in square so I'm going to try it one final time (with a proper press tool) before replacing the oil pump. I was going to try and rig up a cheap endoscope to it beforehand just to see if the leak is accelerated by high rev's/throttle actions or if it's a constant small drip (it doesn't use much oil at all). I can diy and am keen to try and get it ok as it seems (given the weep only) the pump is not so badly worn and I might be able to nurse it through for a time or even fix it with a 100% correctly fitted seal. If not then I think it's pull the engine time and replace a lot of bits whilst it's off which will be a nice project all the same.

Link to comment
Share on other sites

WOT = Wide Open Throttle.

 

If the front has to come off anyway, it’s only a quick job to change the pump over.

 

Thought the subframe had to be lowered to do it with the engine in the bay so i doubt its

that quick a job to do to be honest

Link to comment
Share on other sites

WOT = Wide Open Throttle.

 

If the front has to come off anyway, it’s only a quick job to change the pump over.

 

I don't think it is unfortunately........

 

The pump is approx. £150? But the engine needs removing or lifting significantly at least or the subframe dropping, so I've been quoted in the high hundreds.

Link to comment
Share on other sites

Thought the subframe had to be lowered to do it with the engine in the bay so i doubt its

that quick a job to do to be honest

 

I don't think it is unfortunately........

 

The pump is approx. £150? But the engine needs removing or lifting significantly at least or the subframe dropping, so I've been quoted in the high hundreds.

 

My fault for skim reading the thread :blush: sorry I though the engine was coming out.

Link to comment
Share on other sites

That's the same mistake most make as its an easy assumption, and as i have already said i have proved that its the pump that's responsible, also consider this, the only connection to the seal has to the crankcase and therefor any pressure is a tiny 3mm hole that the oil pump bypass is supposed to flow through, so transferring enough pressure through that to force out the FMS would need to be quite considerable as opposed to hydraulic pressure from the oil build up.

 

What about a slow leaking seal, ie one that isn't seeing hydraulic pressure and the seal isn't physically forced outwards towards the timing star?

 

Could the crankcase pressure effect the rate of flow out of the drain hole to the sump thus causing a build up under extreme rpm......as at higher rpm the crankcase pressure effect would be higher at the same time as the oil pump excess oil passing would be higher.

Link to comment
Share on other sites

What about a slow leaking seal, ie one that isn't seeing hydraulic pressure and the seal isn't physically forced outwards towards the timing star?

 

Could the crankcase pressure effect the rate of flow out of the drain hole to the sump thus causing a build up under extreme rpm......as at higher rpm the crankcase pressure effect would be higher at the same time as the oil pump excess oil passing would be higher.

 

I guess its possible, but i am convinced by the testing i did that with a reasonably sound engine there is no crankcase pressure build up, but if the scenario was that the engine had bad enough ring seal then the combination of a worn pump and a little crankcase pressure woulf slow the oil from the drain hole even further and promote the seal failing faster,

As for your weeping seal it could well be just that and there is no appreciable leakage from the pump, i think if there was you would have seen the seal fail by now, there was a lot of conjecture in the US because the seal either fails by the lips being pushed outwards and the spring being displaced, or the seal was just plain pushed out of its seating, therefore they decided that is was crankcase pressure without examining the pumps or testing for crankcase pressure, and as per usual try everything to fix it by using screws to hold the seal in place only to find that the lips where pushed out and the spring displaced and it than leaked like a sieve.

 

From memory and its about 9 years ago, that i did my oil pump it cost me around £160 for the modded pump, and around £250-300 for a local garage that i knew to do the work, IE on a lift doping the sub-frame enough to get the sump off.

Link to comment
Share on other sites

Don't get me wrong I think oil pump is the way to go, I just like to understand what's going on and to this day there is still some ambiguity on that. The na's not really ever experiencing it, their differing oil drain, the bpu ie higher boost tipping lots over the edge, some seals getting physically displaced, some not but still leaking!

 

I suspect like you say my pump is worn just enough that perhaps on the odd second turbo high rpm usage (possibly combined with when the oils not hot enough) it overloads the seal/drain hole and weeps? but most of the time is ok?

Link to comment
Share on other sites

My weeping one is on stock boost......NA's don't seem to really get them (wonder if any NA-T guys have had issues)

 

I believe the NA pumps have the drain hole nearer 6 o'clock, and there is more room behind the seal.

 

Interesting link here.............it's vvti comparison so it would be good to verify the non vvti's have the same diff's NA - TT, but it would suggest the TT pumps aren't going to deal with excess from a worn pump as well as a NA can?

 

http://my.is/forums/f114/tech-info-difference-between-ge-vvti-gte-vvti-oil-pump-437894/

Edited by Scooter (see edit history)
Link to comment
Share on other sites

I Suspect the issue is due to an increase in acceleration and load - this is adding some inbalance or sideload to the oil pump and it effects the seal - so any bpu or single conversion has both an increase in acceleration and torque as the turbo comes on boost -pot luck weather or not it effects your oil pump -down to too many variables and clearances and temps

NA problems would be simple wear /oil

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.