Does somebody know what is the sensor on the oil drain plug in the picture?

I found oil is leaking from the drain plug after oil change.
I think it need to be changed as soon as possilbe, but the dealer said they don't know what is the sensor on it. They only had a drain plug without sensor slot.

My questions are,
1. What is the sensor for?
2. Is it ok to use a normal oil drain plug without using the sensor?
3. Does the drain plug in the picture used for draining engine oil out when I change it with new oil?
4. If I found the engine oil level was lowered by half, how much I have to fill in additionally?

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Thanks all, I couldn't post reply below.

I ordered a stock plug but it's too small to existing hole.
Where can I find new one? whether it has sensor or not.
How can I know the exact size of the drain plug? I left the States, so It's difficult to find replacement.
I need it since the pitch of existing plug had worn out...

BTW What is difference between washer and o-ring? which is better?

 

you have some aftermarket gauges....like an oil pressure??? That looks like a replacement plug integrating some sort of a pickup. If you replace it with stock you's loose that gau' function.

Put a crush washer in there...I'd probably get a fibre one from the auto parts store....

duh - yes I meant oil temp....

 

more likely oil temperature given the location.

 

That is the OEM oil temp sensor - I have it, too. I also have this leak.

mb

 

I put in an aftermarket temp sensor in the drain plug. I found an o-ring that fits around it well and it doesn't leak - the oem plug has rubber around it too.

 

OEM optional oil temp gauge sensor. Just get new washer.

 

Just a heads up that the washer may not work to fix the issue - it didn't with my car.

Mine was stripped badly. Could have done a helicoil but we decided to do it right once and for all: got a new oil pan and drilled in a spot for the sensor. The tech. said that he wouldn't be surprised if all of these things leak because the sensor/drain plug doesn't match well with the oil pan since it has less threads, so people turn it and turn and turn without any real idea of when it's tight.

That's my understanding of it and how my car would always leak oil from the drain plug no matter what. Perhaps I got a bad unit or just had a really ham-handed soul change my oil at some point. Either way, it's now drilled into the side of the pan and I can have a drain plug meant for the pan.

Good luck!

mb

 

FWIW, you can use a stock VW drain plug, but won't have the temp sensor. The VW plug is maybe 1/8" longer - I ground mine down - but you probably don't have to shorten the plug if you check the clearance inside there.

The advantage of the VW plug is that VW was wise enough to put a 17mm head on theirs so it's more difficult to strip the plug head. They also use a copper crush washer instead of the prone-to-swelling rubber OE washer on the Minis. Just do NOT overtighten!

Good luck!

 

The OEM drain plug asked about comes with a copper washer. Just get a new washer each time you change your oil.

 

I’ve just discovered I have the “stripped threads” problem, but it hasn’t progressed to the point of a leak.

My MINI is a 2004 “S” that I purchased new. Before I took delivery, I had the dealer install the auxiliary gauge kit. That kit included a VDO oil temperature gauge with the sender located in a replacement drain plug at the oil pan. Now, after about 140,000 miles and a lot of oil changes, I’ve discovered that the sensor, which has only four threads with which to engage the threads of the drain hole in the pan, has slowly been eating the threads in the drain hole. While it can still be tightened, the aluminum threads in the drain hole are now visibly distorted, so I’ve replaced the sender with an OEM drain plug (which has nine or 10 threads and which fully engages all the threads in the drain hole). Result – the oil temp gauge no longer works but at least I won’t lose the drain plug and spew five quarts of Castrol on the road.

I’m an old-fashioned analog guy, so I’d like to get my oil temp gauge working again (yes, I know a scan gauge would probably do the job nicely, but I far prefer a nice red pointer I can pick up with a quick glance, knowing that pointing to 12 o’clock means all’s well). However, a careful check of the VDO site shows they make only two temperature sensors with the requisite M14 X 1.5 thread. I have one, and the second has the same number of threads but a shorter sensor portion extending into the hot oil. Since having an inadequately short threaded portion is the cause of my issue, this seems to eliminate the possibility of getting a drain plug sensor, since neither the one I have nor the other one will utilize the undamaged threads in the rear half of the drain hole.

So, my questions are:
1) Has anyone else experienced this issue? If so, how did you solve it and retain your analog oil temp gauge?
2) Where else, that’s not incredibly inconvenient can an oil temp sensor be mounted? I really don’t want to tap a different hole into the existing oil pan, and a new pan, such as mbcoops used, is not inexpensive!!!). I do have an oil pressure gauge mounted with an adaptor similar to the Craven tapless adaptor. Can an oil temp sensor be mounted there? What kind of correlation will there be between temps taken there and temps taken at the drain hole?

Any and all suggestions welcome!

 

I just replaced my oil pan on my #24 MC40 because of the stripped hole. Sure it is easy to just pull the Oil Temp sensor and tap the hole a size bigger and insert a larger plug into it and drip is resolved. But you loose the Oil Temp Sensor, unless you drill and tap the oil pan to continue to use the sensor. And to do that you need to drop the pan so you can make sure your cuttings can be cleaned out of the pan, so if you are going to drop the pan to do all that work... just replace it with a new pan, you can find them as low as $128.00, a couple of new gaskets and don't forget to get spare copper crush washers for replacing when you do your oil changes, and all is good with the world.

To respond to your questions...

1. What is the sensor for? Oil Temp Sensor... as discussed..

2. Is it ok to use a normal oil drain plug without using the sensor? Yes you can, they run about $4.00 and with the gasket on it I recommend replacing it every couple of years.

3. Does the drain plug in the picture used for draining engine oil out when I change it with new oil? Yes it is, and Yes they should be replacing the copper crush washer ever time they change oil.

4. If I found the engine oil level was lowered by half, how much I have to fill in additionally? Well.... engine oil capacity is 4.7 quarts (4.5 liters) so half would be... 2.35 quarts (2.25 liters). But use the dip stick to determine the assumption is if the Dipstick Indicates half way between full, how much oil to add... I have no idea, I would add slowly and check the dipstick as I added every quarter quart/liter.

Parting shot... when my oil pan was removed the internals of the engine were inspected (the car has 248K miles) discovered the oil pickup was clogged up, it was still working, but it was given a good cleaning and that put a smile on my face.

History, most guys under the car, just use the German shade tree mechanics rule for tightening the drain plug/temp sensor "Guten Tight" (Pronounced...Good 'n tight) seldom do they bother using a torque wrench and tighten it to spec, matter of fact if it is dripping, forming a drip, or leaking they figure, it just needs to be tightened a little more... and that is what causes the threads to be stripped out.


Best of luck.

Motor on!

 

Well done, but the questions were posted over 6 years ago.

 

I just recently bought a spare oil filter cover/cannister and had a hole tapped on top of it. Waiting for the next oil change to swap the sensor over from the oil drain plug. It should show about the same temps as at the drain plug.

 

Thanks - that sounds like a good idea.

How thick is the oil filter cover where you tapped it? (I presume you did so in the center of the hex on top where the filter wrench fits).

What about the prong where the wire attaches to the sensor - does it stick out so far that it will interfere with the filter wrench? Or is this a case of once the sensor is in place it never needs to be removed because you just disconnect the wire and then remove the filter cover the same as always?

btw, I'm not using a "normal" filter wrench. I couldn't find one when the car was new, so bought a Sears socket the right size and cut off the excess socket depth so it would just fit in the available space with a ratchet on top. I'd have to check, but I don't think I left much clearance between the top of the filter cover hex and where the square drive fits into the top of the socket. Maybe I should just buy the "normal" filter wrench - I've seen them for sale on several sites.

 

Greetings, Please advise as to common oil leaks...EFN

 

I can't speak for others, and this may or may not be typical, but here's my 140,000 miles of experience with a Gen-1 "S".

Two oil pan gaskets replaced (both under warranty) because they leaked. The second replacement is still in service and not leaking.

One leak at the oil filter canister because I didn't get it on tightly enough.

Currently have three or four minor drips from various seals on the engine - I'm not going to bother doing anything about them (other than to put a piece of cardboard under the car in the garage to keep the oil off the floor) until I have other, more major, work done.

Unlike some other posters here, my drain plug was not leaking at the time I noticed the distorted threads. I've temporarily replaced the temperature sender/drain plug with an OEM drain plug and am living without an oil temp gauge until my next oil change, when I'll re-locate the sender, most likely to the filter canister cover.

 

" 3. Does the drain plug in the picture used for draining engine oil out when I change it with new oil? Yes it is, and Yes they should be replacing the copper crush washer ever time they change oil. ""


Here is the senor itself for the Under toggle bank Aux Gauge kit 82940004581 , if your is damaged or missing, some people removed these at shops and replaced them with the normal drain plug, then the customer saw the gauges and the oil temp would not work.

http://www.ecstuning.com/Search/SiteSearch/82940004581/






And here is the crush washer: 32411093596

http://www.ecstuning.com/Search/SiteSearch/ES2580798__ES2675477/

 

While the image above was taken at an angle, I think you can see that there are not a lot of threads on the sensor (specifically, there are only four threads), and that's the reason people with this sensor eventually have problems with the threads in the drain pan. The OEM drain plug has more than twice as much threaded length (I think it's eleven or twelve threads total), and if properly torqued when re-installed, should never damage the threads in the pan. Fortunately, when the sensor pictured above eventually does distort the pan threads, there are still lots of pristine threads left in the pan into which an OEM drain plug can be installed without problems.

The unavoidable consequence, of course, is that replacing the sensor with an OEM drain plug removes from your oil temp gauge the signal it needs to report temperature. Some people apparently have had a new M14 X 1.5 hole put elsewhere in the oil pan and the sensor lives there permanently. Provided you don't leave any metal bits and pieces inside the oil pan when the hole is tapped, this is probably the best solution. Others, me included, don't want to do that because if you mess up and ruin the pan, replacement is an expensive proposition. I've seen a couple of people post that they've drilled the top of the oil filter canister and put their sensor in that location, and that's what I'm considering doing. I've got about 9,000 miles (per Blackstone Labs latest analysis on the oil I drained from my engine) before I need to have a solution ready to go, so over the winter I'll probably prepare a replacement oil filter canister cover with a sensor and install it at the next oil change.

It seems to me that MINI should have specified a sensor with as many threads as the drain plug has. However, the sensor and gauges are from VDO and as far as I can tell VDO does not manufacture a 150-degree C temp sensor with M14 X 1.5 threads that has a threaded portion equal in length to the threaded portion of an OEM drain plug.