Mini ONE 1.4d: Bubbling from radiator bottle... is it the cylinder head?

 

So today we have a MINI ONE 1.4 diesel and guess what... it's overheating! Coolant is being lost somewhere and we find that it is bubbling out of the header-tank. My first guess in this situation is the head-gasket, but for a cheap fix (possibly, but better than going straight to ripping a friend's car apart) we tried a new radiator / header-tank cap, which was fitted yesterday and, although it has reduced the bubbling problem, there is still some coming out when the engine is warm, coolant lost and the temp. needle creeping up. 

This week the poor running has begun... occasional juddering, drop in revs and the odd misfire noise. Hmm... I have said to keep using it until the running becomes unmanageable (provided it's kept watered and is not overheating of course!) and am hoping for a weekend of better weather so I can have a proper look round it and, if need be, open it up. Watch this space.

EDIT: With not many tell tale signs of the head gasket being blown, someone has kindly suggested that the water pump is failing and not circulating coolant properly, so here's something else to look into. Yay!

E30 318i: Correct Temperature Sensor fitted (Brown Plug) + wiring/loom issue

The temperature gauge in the dash has not worked since I bought the E30, which was a little worrying on my 250 mile drive home, but the car does not overheat. Oh, it has some issues with the cooling-system, like the heater-matrix pipes fitted incorrectly and an air-lock at the back of the head, but hey it doesn't overheat. Still though, I thought it best to get the bottom of the faulty temp. gauge for peace of mind, particularly with summer coming / just about here.

The M40 has two separate temperature sensors that are independent from one another. The temperature gauge works from the 'Brown plug' sensor to the rear of the head [right in pic]. The forward sensor is the 'Blue plug' [left in pic] and that connects only the DME (ECU) to tell the car if the engine is cool or warm to help with cold-start procedures. A single sensor cannot be used for both purposes on these older engines as the resistance value ranges required for each function differ, the DME being a digital circuit and the temp. gauge still working in analog. [You can read more about this on the E30 Zone Wiki HERE].

MULTIMETER TESTING:

The temp. sensors can be easily tested with a multimeter set to 20k ohms resistance. 

The Blue plug is a two-pin sensor, so test across both terminals with the multimeter and you are looking for a reading of 4-4.5k ohms for a working sensor. This sensor and plug can be accessed easily without removing any parts from the engine.

The Brown plug though will require removal of the lower inlet-manifold to access the sensor for testing or replacing. This is a single pin sensor, so place one probe of the meter to the terminal and the other to a ground-point in the engine bay or against the block/head. Expect a reading of between 1k and 1.5k ohms for a working sensor. To test the Brown plug sensor without removing any parts from the engine, you can apply the multimeter to Pin 4 of the C101 connector (main wiring loom plug in engine bay) which is easy enough to get at, or at Pin 26 of the blue connector to the right side of the instrument binnacle, though the binnacle will need removing to do this.

WRONG SENSOR / CONFUSING WIRING LOOM:

All M40 engine wiring looms use a single pin temp. sensor on the brown plug that earths through the engine block and have only a single wire in use leading to it. Some looms, using components destined for other BMW models, are known to have a second wire leading to the Brown plug temp. sensor which is redundant on the M40 motor, though this is rare and seen more often on 6-cyl. M20 looms. My car has one such loom, however and I realise that this is what has caused confusion in the past and led to the wrong sensor in fact being fitted...

Upon inspection, the rear temp. sensor fitted to my E30 is black, not brown and has two terminals. The second pin means that the sensor body earths back to the loom and not through the block so, if the redundant earth wire in my loom is not connected to a ground-point then the sensor was open circuit. I guessed that someone had ordered a second Blue plug sensor by mistake and fitted that, but it turns out the part number doesn't match and the sensor is for a completely different model engine entirely. The reading from the multimeter was over 11k ohms, something like 7.5 times what it should be! That sensor was never going to work with the E30 temp. gauge circuit whether it was earthed or not.

I ordered the correct single-pin sensor with the brown base from mr-wiper on eBay, who also supplied my Bosch spark-plugs. It was only £7.69 delivered. My temp. gauge now works, but this may also be due in part to removal of an air-lock at the back of the head due to a heater-matrix problem so coolant is now flowing properly round the area of the sensor. 

A BIT MORE ON WIRING LOOMS:

Brown / Violet, brown being the main colour, denotes that the power source provided from the temp. gauge circuit is earthing through this wire and does not need to be a closed circuit back to the gauge. The other wire is either not wired in to the loom or goes to a body-earth anyway, so earthing the sensor through the block will make no difference. This colour coding is the same for all wires in all BMW looms, I would imagine most cars are the same.

BMW E30 Heater Matrix Hoses Configuration - Right and Wrong way round + how to bleed matrix / remove air-lock

My E30 had little or no hot air from the blower inside the cabin. I have heard it is common for the two hoses running to the heater matrix to be fitted back to front, so the flow of coolant through the core is reversed. This causes air locks and severely reduces the amount of coolant flowing through the heater matrix, thus no hot air. 

The reason these hoses so often get fitted incorrectly is due to their location and the way they look when fitted. It appears obvious that the upper hose (back of cyl.-head to heater) goes to the upper stub on the heater-matrix and the lower hose (side of block to heater) goes to the lower stub on the matrix. The hoses look happier this way round, but the matrix and heater-valve are designed in such a way that flow is interrupted and causes the air-lock. 

The correct way round is actually with the upper hose connected to the lower stub and the lower hose to the upper stub, which does of course appear to be back to front, but is essential for correct flow of coolant round the whole engine, not just the heater-core. The correct and incorrect hose configurations are shown in the pictures below.

RIGHT:

WRONG:

How to Bleed system and remove air-lock from Heater-Matrix:

** This is not the normal air-bleeding process when refilling an empty system with coolant, this process is to bleed a system with the air-lock at the back of the head and / or the heater-matrix full of air. **

1. Ensure heater-matrix hoses are fitted the correct way round, if not swap them over. [You should notice if there is an air-lock that no coolant comes out of the hoses when removed from the matrix and the stubs appear dry].

2. Fully tighten the lower [inlet] hose.

3. Leave the upper hose disconnected from the matrix. 

4. Remove the radiator bottle cap. Assuming the coolant level is up to the halfway / max. mark, there should be some gulps of air and the coolant level should drop slightly in the rad. bottle.

5. Cut the bottom off a 2-litre drinks bottle and fill it with water, holding your hand over the lid.

6. Dump the water from the drinks bottle into the radiator bottle, allowing the weight of water to push the remaining air though the system. Water should start to come out of the upper heater-matrix hose from the head. Block this hose with a finger.

7. Continue to top up the radiator bottle with water until water begins to flow out of the upper stub on the heater matrix and quickly refit the upper hose, which can now be fully tightened.

8. Drain the radiator bottle back down the halfway /max. / fill line.

** You should be good to go, but can now bleed / top-up the system using the usual bleeding procedure if necessary. **

E46 318i - Broken Coolant Hose! [11537572158]

 After about 650 miles in the E46 Touring the radiator light came on. Just the amber warning, to let me know it was getting low, not the red warning when it is running out and I refilled about 1.25 litres of water / coolant to the engine. This seemed about right to me, as I feared it may be using a bit of water and there was plenty in when I bought the car so 1.25L in 650 miles isn't catastrophic and can be lived with.
About two weeks later the radiator light came on again and I dutifully refilled 1.25 litres, but the car had only covered 120 miles so I knew something was now amiss, only for the light to come on yet again after just five miles of my six mile round trip to work. Under the hood with the engine running I could see a huge pool of water in the under-tray and a drip, which after much tracing turned out to be coming from a slim rubber hose that connects to the left side of the cylinder-head [N42 engine]. It was a constant drip, but when I wiggled the hose-end the coolant began to spray round the engine-bay, so here was the culprit. Turns out the hose-connector into the head was completely sheared off, as you can see in the pic, and should extend about half an inch into the housing. The only thing holding any water into the upper engine at all was a single M6 thread screw.

The hose in question was BMW Part No. 11537572158, shown in the diagram connecting the thermostat to the cylinder-head. This is a common fault I am told on N42 and N43 engines, along with several other coolant hoses that have plastic end connectors, particularly in the US where kits can be purchased to convert the brittle plastic ends to aluminium ones. This seemed unnecessary for me, given the cost of a replacement part and the age of the car.

As there are so many coolant hose variants, finding the right used OEM one on eBay and the like can be difficult, but they do pop up. I was able to get a new spurious part through work for just £18, but I'm sure commercial motor factors will not be much more expensive as long as they have stock. Spurious hoses tend to come with a new rubber O-ring fitted. BMW dealerships will charge a premium, but at least fitment is guaranteed and they are revised parts, though these may not come with the rubber O-ring which will also need to be ordered.

E60/E61: Hidden OBC Menu in Instrument Display - view R/T measurements + CANBUS data

There is a hidden way to access real-time CANBUS data through the instrument binnacle. The guide here [written by scoopz for m5board.com] mentions the E60 M5, but I used this on a 530d manual and 525d auto, so it does cover all E60/E61 models. It may work, or there may be a similar system for Fxx Series BMWs, but I have not had a chance to examine this yet.

Measurements that can be viewed include true engine temperature, true engine RPM speed, true vehicle speed and loads of other bits of information that the CANBUS system records, but the iDrive does not normally display.

LINK: https://drive.google.com/open?id=1nHxeTpZLO2X5PkZQse10ureUOTBdBJx6

GUIDE: [written by www.scoopz.com for m5board.com]

*ACCESS PDF GUIDE FOR ACCOMPANYING PICTURES*

To access the menu follow these steps:1. Ensure your engine is OFF but ignition is in stage 2. (For

     those with comfort access just press the start/stop button
     twice once in the car without your foot on the brake)

2.Press and hold the odometer reset button (from now on I shall just call it the button) for 6 seconds, during which it will

show an oil icon, then a warning triangle. Keep holding and release when it shows: 01.__ FGSTNR

After a second or two the 01.__ will be updated with 01.00 and the last 7 characters of your VIN/Chassis # will show: 01.00

FGSTNR

CU12345

     Make a note of the numbers, this is important as you will need
     them in a minute to unlock all the menus because at present you
     can only access menu 01.__, 02.__ and 19.__
Now that you have made a note of your VIN number you need to add all the individual digits together so if your VIN was CU12345


Then you need to do:
1+2+3+4+5 = 15
This number [15 in this example] is you magic unlock number and is needed for step 6.
Press and hold the button for two seconds until it shows(press button 2 seconds)
01.__
Whilst it is displaying 01.__ repeatedly press the button to cycle through the menu’s incrementally:
01.__
(press button)
02.__
(press button)
03.__
(press button)
until you get to 19.__ at which point stop and wait for it to show
19.00
LOCK: ON
CODE: 00
     Now press the button repeatedly to increment the CODE eg:
(press button)
CODE: 01
(press button)
CODE: 02
(press button)
CODE: 03
(press button)
...until you get to the number you calculated in step 4, your unlock code, in this example 15:
CODE: 15

Once you have reached your unlock code wait a few seconds and it should jump you back to 01.00 and all the other menus will be available.
There are 21 top level menus and some have sub-menu’s, for example:
01.__ 01.00
      01.01
      01.02
      01.03
02.__ 02.00
03.__ 03.00
04.__ 04.00
04.01 04.02etc
To change top level menu’s press the button for 2 seconds until the last two digits turn to underscores (XX.__) then release the button and quickly press the button repeatedly to increment through the top level menu’s, e.g.:
(press button 2 seconds)
01.__
(press button)
02.__
(press button)
03.__
etc
Once you arrive at the menu you want to go into just wait a few seconds and the two underscores will be replaced by double zeroes (XX.00) and every subsequent press of the button will cycle you through the selected menu’s sub menu:
04.__ (wait few seconds)
04.00
(press button)
04.01
(press button)
04.02
(press button)
04.03

10. Some menus don’t have sub menus so waiting for the to display




XX.00 and then pressing the button again will activate that feature, try it on menu 02.00 and it will carry out a dashboard

test and move all the needs. Press and hold the button for two seconds until the last two digits turn to underscores then release and keep pressing the button until it shows:02.__

     (press button)

02.00

     (press button)

     Dashboard will do strange things.



Ok so that’s a run down on how to access the menus and move around the different levels of the menus. I systematically accessed each menu and it’s sub menus and photographed each one to create a rough guide as to what is shown, most things I haven’t got a clue what they are but some things like current true speed, rpm and rpm limit are useful.

E46 Clubsport: Loss of coolant... split radiator!

The Clubsport is starting to become a bit 'whatever next' lately. Amidst the other post new year jobs I forgot to mention the coolant expansion-tank that sits next to the radiator had swelled and split down one side, so a new one was duly fitted.

Last week the sudden loss of coolant returned, with the puddle in the same place under the radiator, but no visible sign of a leak. Nath assumed it to be the radiator-cap, so we pressure tested it in work and it's fine. Then we pressurised the rest of the cooling system and this is what we found - the radiator has burst along the top. A new radiator is going straight in, but the fact remains that something is still pressurising the cooling system and needs to get sorted.