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. **

E30 318i: New Bosch spark plugs + correct coil fitted

With the car still misfiring a bit, I turned my attention to the plugs and HT leads. All appear fine. The coil works because there is a spark. I inspected the plugs, a set of NGK R that don't look particularly ancient, expecting one or more to be wet with unburnt fuel from a combination of misfiring and running an over-rich mixture from tweaking the air-flow meter [AFM]. I noticed that the plugs were in fact all dry and totally black with soot at the tips from over-fuelling, but their condition seemed fine. This matched the points in the distributor-cap, which were also blackened.

The spark plugs were working, but they didn't seem to fully igniting the mixture and performing weakly, so I turned my attention back to the coil. A previous owner had fitted a universal 'Sports coil' and judging by the shiny casing it doesn't look too old, so I couldn't see how it could be at fault. Thats when I noticed the terminal connecting it to the HT lead. It's about 10mm wide and has a metal inner lining. There is a screw at the bottom holding it in. This is obviously designed for a different type of HT lead than fitted to BMW, as the lead has a rubber plug where

it contacts the copper casing of the terminal in the coil. The metal terminal in the HT lead is designed to fit over a stud inside the coil-terminal, which is what I've always seen before, not just in BMW. This means the only contact being made by the main HT lead was its very tip touching the screw at the bottom of the coil-terminal.

I swiftly ordered a used OEM Bosch coil unit from eBay for £15. A 'Sports coil' type with the correct end was about £35, but I figured it was best to go original, at least for the time being while I iron out the M40 engine's running problems. While I was at it, I bought some OEM Bosch spark plugs for £13, which is cheap and I thought I may as well rule out plug condition as a factor with not knowing how long the incorrect coil has been fitted to the E30. 

F10 530d: Black leather rear-seats and door cards WIN - front-seats FAIL!

Lovely front seats do not fit.

Thought I would treat the F10 to a nice leather interior, replacing the tired and fluffy cloth front seats and scratched / dirty door cards, after spotting a complete set from a 2014 car on eBay. I managed to get £100 knocked off the price and drove down to Stourbridge to grab them with a distinct feeling that it was too good to be true. I had to climb nearly 20 feet up a ladder to retrieve them, but they were seriously mint - honestly, not even a mark on any bit of leather - so I parted with the measly £300 and brought them home.

My gut feeling turned out to be right. While the rear seats and door-cards are a perfect fit, the front seats are not. From mid-2013 onwards the F10 floor-pan was updated, along with the mounting-points for the front seats and this means that the runners on my new seats are a couple of inches narrower than on my original 2010-13 seats, which are clearly wider at the base. There is no way to swap the runners, the seats are just too different in design and I will write a more detailed guide on this soon. Annoyingly, the electric plug fits and the motors operate, though they throw up too airbag warnings.

Door cards are straight swap.

Modifying the seats or floorpan to fit is just too much work and will not look very nice, so the only way to go is wait until a pair of front seats for a 2010-13 car come up and try to part-ex mine or at least sell them later. Either way, this could end up costing me more. Regular SE seats are quite thin on the ground for the earlier cars and M-Sports are upwards of £400.

Rear seats fit great.

** Correct seats now acquired here: https://beemerlab.blogspot.com/2016/08/f10-530d-correct-front-seats-acquired.html **