So my Mini has a massive oil leak... and from reading this forum and others the main causes are:

• Crank Postion Seal
• Front Main Seal
• Rear Main Seal
• Oil Pan Seal
• Valve Cover Seal <-- Not likely the cause but why not

Also plan on changing the SC and Transmission Oil, Replacing the plugs, coil and wires, and cleaning the $h!t out of it

I also want to add a few go fast parts, it has a Alta 15% pulley and Alta CAI from the previous owner but I want to go to 17% so I could do a 2% crank (but I loose the harmonic balancer, I heard that the minis don't need one ) or I could leave the stock crank and replace the pulley...

So while I'm in the with the car mostly apart what else should I do? On my other fun car there was a laundry list of things to do when you replace the timing belt because its a pain to get in there so you might as well knock it out.

Other Items from reading:

• I have heard that a tensioner stop is a good idea
• Timing Chain tensioner

Please let me know if you think I should add or remove anything from this list

Also if anyone has a recommendation on where to source the parts... the dealer is about $500 for everything, MiniMania OEM is $340, and MiniMania Value Line is $200 (Not sure if I should trust the Value line)

Thanks!

Mike

 

Oil Filter housing seal, (gasket).
As for parts sourcing, I would check out Pelican Parts or Way Motor Works

 

Thanks for the mention, gumbedamit!

Mike - check out our extensive tech articles here: http://www.pelicanparts.com/techarti...tech_index.htm. They will help you with tackling a lot of these jobs that you have listed. If you have any questions about any of them please let me know as I am here to help.

For the harmonic balancer I'd go with a Genuine replacement or go with the ATI as it's recommended as the best around for R53 MINI owners. There are a lot of great threads around on NAM about % pulley upgrades. If you'd like, I can put together a quote for all the parts you need I'd be happy to so. Just shoot me a PM.

 

Figure out where (in general) the leak is originating from, *then* repair/replace as necessary. Messing with seals and gaskets that aren't leaking is asking for trouble; throwing money at parts that aren't broken is a waste of money.

Clean underneath and around your motor and find out where the "massive" leak is coming from. You do *not* want to do the front or rear main seals if you don't have to, and they're likely not the cause of your leak.

The CPS O-ring is a likely leak, as is the Cam PS O-ring - but you won't know "if" until you clean the oil off first and look for fresh leaks. If the C(rank)PS O-ring has been leaking for awhile, it can look like a major leak - but it's not. Both are relatively easy and cheap to replace. Pan gasket? Possible (not unheard of) but again, you don't want to pull the pan if the gasket isn't actually leaking.

You'll get used to sticker shock from the dealer. Always check with the aforementioned sponsor sources. They're not only extremely knowledgeable and helpful, they are Mini enthusiasts too and they only sell quality parts. Trust them!

 

Thanks for the info... I feel I should have elaborated more on the condition of the car and the volume of the leak.

It's a 2003 S, it was being driven by someone who has zero respect for anything, it went 12k miles without an oil change, there was less than a quart in it when I got it back. It was sitting for 6 months (winter) during that time so I assume anything rubber was dry and possibly froze so I would rather be safe. As for the leak, it lost 2 quarts overnight (about 14 hours) so tossed some cardboard under it to see where it was dripping from and the source seems to be the front corner of the motor... so I'm really thinking front main is the culprit, The CPS ring is, from what i've read, a timebomb so its on the list, and the drain is stripped/ing (lots of metal in the threads of the drain plug) so I am going to pull the pan to either re-tap it or replace it.

Also pulled the IC today and it looks like the air filter degraded at some point and got sucked thru the SC So I may have to pull the whole thing out and check it out.

Thanks,

Mike

 

2 quarts in an hour would make me wonder whether something is cracked. When shut off and the car at level parking position, the oil is going to be in the oil pan, not up high enough to leak out any crank level outlet.

 

r53coop is right. If you're losing all that oil while parked, it's coming from the pan. I'd also reckon that at 2-quarts in 14-hours, you would see exactly where it's dripping from.

Since you know this car was mistreated by the previous owner, it's not too far-fetched to imagine the car driven over a stone and/or speed bump which possibly cracked the oil pan. If the pan turns out to be the culprit, you could easily source a used one on eBay, or through one of the several vendors that part-out cars on this forum.

 

Sorry I'm not as proficient on the mini's anatomy, are you saying that the front main and rear main don't have oil contact while the car is sitting?

Mike

 

The illustration below shows the axis of the front/rear main seals.

While engine is idle, all motor oil drains into the oil pan, seen at bottom of engine, so no, oil would not "drain" from the seals, or anything else above the pan for that matter.

 

So I probably have a bigger problem, if it got down to one quart there is either a crack/hole in the pan or the drain plug is leaking as well.

Does the blower trick work on minis?

 

I'd much rather change out a drain plug or even the entire oil pan than replace the front or rear main seals...

 

I've done all the seals on my other cars, so I'm not too worried about doing it. My main thing is I don't want to have to get back in there again if it ends up being one of those.

I will pull the pan first and look for damage on the seal, I have to do it anyways

 

I think there is a UV dye for oil. With it you can see where any new leak is with black light.

I am thinking that if you pressure tested the intake system that also pressurizes the engine if you do not remove the oil filler cap, you could see the leak if the oil pan was cracked. Talking 5 to 10 PSI so pretty sure it would not cause issues in the engine.

Two quarts is pretty big hole somewhere when the engine is not under pressure.

 

Rear main seal involves dropping the transmission. I would definitely take that one off the list for now, and try the oil pan and CPS gaskets first.

 

Update...

I got back out to the garage tonight finally...

I took the oil pan off, and there was a good but of sludge :(



But I got it all cleaned out and there does not seem to be any cracks, there are what seem to be a bunch of casting remnants, is that normal?



Good news the crank and rod ends look good





The back of the flywheel is a little rusty, don't know if that should be a concern or not... could it have been flooded?





On the block there is a good bit of gunk above the pan on the transmission side makes me think there is another oil leak in the valve cover gasket, the back of the motor right below the valve cover looks similar.




Also pulled the SC will need to check it out for air filter pieces.

 

Your last pic - where the electrical plug has been pulled - that's your crank position sensor (CPS) and all of that oil on the block is likely coming from the leaky O-ring on the sensor. I don't know what it is that you have the paper towel stuffed into - is that where the dipstick tube goes?

Anyway, neither of these things would generate the kind of oil leak you seem to be experiencing.

 

Yeah I had to pull the CPS to unplug it, it was caked in grime and I couldn't see the red fastener, and the seal is bad so i will be swapping it.

And yeah thats a paper towel in the dipstick hole... although it's pointless now that the pan is off...

Mike

 

Agreed...

Are you positive that the oil loss (2 qts!!!) occurs when the car is parked, or are you losing it while running the engine? That's some significant oil loss if parked, but if the latter, that opens up new possibilities, and I'd suggest you look more closely - starting at the oil housing area.

Possible failure points here are:

1) Oil filter housing to engine block gasket
2) Oil filter cap not screwed on properly (or O-ring missing?)
3) Leaking from oil filter housing to heat exchanger (2 seals here)

An area you can also survey is the crankshaft seal on the timing cover as well as the timing cover gasket, however, you must remove the belt, crankshaft pulley, belt tensioner and idler pulley to replace either of those gaskets/seals. If you go that far, there are also two internal oil seals inside the timing cover that you should change.

 

I am sure it was while the car was sitting and it took 3 quarts to get it back to full, so by my math thats 2 quarts, right? The threads on the drain plug were also stripped, so that could have been a contributing factor but it was dripping from the passenger front corner of the motor... Also the pan gasket was hard like plastic, it breaks very easily. I don't have a new one to compare it to but I assume it's supposed to be rubber/silicone, right?

I also pulled the heat shields and looked at the oil filter housing, there is oil on the bottom bolt so it could be leaking from there as well.

Mike

 

The gasket does have a hard plastic shell/carrier along with metal grommets to prevent over-torquing, but the center raised double-ribbed portion is soft.

Over time, all these seals/gaskets/o-rings that we've been discussing DO harden and/or compress and leak oil. I would recommend that since this is definitely an oil-retention issue, and since you have things in a state of disassembly, it would be beneficial to replace all of these oil-related rubber parts from top to bottom, making sure to adhere to proper torque values when reassembling.

It's not expensive, but it's a series of fairly straightforward tasks that will take some time. I ran through all of this with my engine, and now she's dry everywhere.

The list, from top to bottom is as follows:

Valve cover gasket
Camshaft sensor o-ring
Crankshaft sensor o-ring
Oil filter housing gasket
Heat exchanger o-rings (2)
Timing cover gasket
Crankshaft front oil seal
Timing case cover seal - Upper
Timing case cover seal - Lower
Oil pan gasket

 

Ordered a new baffled oil pan, Oil pan gasket, valve cover gasket, cam sensor o-ring, crank sensor o-ring, and oil filter housing gasket from Way Motor Works, I need to check the timing cover and chain tensioner.

From what I've been reading on here the heat exchanger is a bear and you should just do the whole thing rather than just the rings, thoughts?

I have a question about doing the crank (front main) seal, does the mini crank pulley use a woodruff key or is it pressure mounted?

Mike

 

Not positive I'm understanding your question. The heat exchanger needs to be removed from the housing (through passenger side wheel well) in order to replace the rings.

It's a press fit.

 

Not positive I'm understanding your question. The heat exchanger needs to be removed from the housing (through passenger side wheel well) in order to replace the rings.

It's a press fit.

 

I was referring to this thread https://www.northamericanmotoring.co...sket-help.html

Saying to replace the whole oil cooler, rather than just the seals. It seems to be a persistent problem for many if they only replace the seals.

Mike

 

Got it...

Well, my initial reaction would be to say that if the cooler is functioning properly, then save the $120 price of a new one and change out just the rings.

That said, nearly a month ago, I replaced my oil cooler (see this thread) which failed internally, allowing oil to leach into the coolant creating a world of hurt... so maybe yes, pickup a new cooler to avoid potential failure down the road.

As part of that project, I replaced the filter housing gasket and the two o-rings, which were like hard plastic - no longer effective at sealing. Best way, IMO to remove the housing, it to break it down and remove separately it's three components; first the filter cap, then the oil cooler, then the housing itself, both of which came out the passenger-side wheel-well. With not much room to work, a 13mm magnetized socket was invaluable to making this process much less painful.