Heater hose M50

[Frog]

Which hose do I need to use? The m50 one (64211394293) does not fit. I've been to 3 different auto parts stores and can't find one that will work. It is flanged, which makes it hard to find a compatible one.

[Wishno87]

I just used the E30 one.

[Frog]

Which one? 325i, 318is, 318i

[Wishno87]

E30 m20

[asubimmer]

lol mine is off a 3.0 csl

[Frog]

If anyone has a working part #, it would save me from guessing!

[Chrisv006]

I used bulk heater hose. 3/4 off the block reduced down to 5/8 with a coil spring on the bend into the heater core. Tightened it all with clamps. My spider hose is totally DIY too.

[samiam3356]

You've got them hooked up backwards anyway. Back of the head goes to the bottom of the core.

Edit: the e30 one supposedly has the perfect 90 bend.

[two240s]

It would help a little if you bent the heater core line down/towards the pass. side. Find something that will fit inside the pipe and you can bend it a little...be careful though.

I found something at the parts store but had to cut it down for length.

[328ijunkie]

You've got them hooked up backwards anyway. Back of the head goes to the bottom of the core.

Edit: the e30 one supposedly has the perfect 90 bend.

Back of the head goes to the top hose... Its the hot flow from the motor to the valve for the HC...
But yes, use the stock E30 hose... The M50 one doesnt fit because its made to be straight, as it goes into the E36 Heater valve dist block.

[samiam3356]

Back of the head goes to the top hose... Its the hot flow from the motor to the valve for the HC...
But yes, use the stock E30 hose... The M50 one doesnt fit because its made to be straight, as it goes into the E36 Heater valve dist block.

Cooling System

The early E30 radiator and expansion tank will not work unless you start getting into custom lines. The Late E30 and E36 radiators will work. Use the M50 hoses, you may have to trim the top or bottom radiator hose. You can also use the m42 radiator, but I am not sure what lines to use. This will result in a cleaner looking bay, but less cooling capability due to the smaller core of the m42 radiator. The hose from the back of the head to the heater core I use an E30 one, it has a perfect 90* bend. This hose goes to the bottom inlet on the heater core the hose from under the manifold goes to the top. I also found that I had to bend the pipes on the heater core down and towards the booster to clear the intake manifold, not a lot, maybe 1/2 inch.
The cooling systems can be a pain to bleed. I recommend either doing it on a hill or putting the front of the car on jack stands, it has worked first time every time I have done it.

You are going to want to change the coolant sensor in the head under the intake manifold to the brown top E30 one so your cluster will read accuratly. It is going to be the one furthest from the front of the motor.

Before you add coolant I would reccomend changing the thermostat housing and upgrading to the aluminum one. The factory plastic ones are prone to cracking.

You need to use the E30 mechanical fan, not the E36 one. I don't know if the m42 fan works, but I know the m20 fan work. Maybe somebody can confirm the m42 yay or nay?

-Hose for M42 Radiator- Dayco part number 71901 http://www.e30tech.com/forum/showpos...0&postcount=74
or you can use e34 hoses cut down.



If your right I def have mine hooked up wrong as everything I've read said to hook the back of the head to the bottom

[328ijunkie]

If it was hooked up like that the hot coolant would flow throught the Hcore no matter what then stop when it tried to exit. Coolant flows from the front of the motor to the back...

[samiam3356]

Would love someone else to chime in and clear this up. I read a lot on this and never once did I see someone say that the back of the head goes to the top.

[328ijunkie]

Customers M20 HG job, the Head hose is disconnected the main spider hose isnt.

[samiam3356]

I thought it was reversed for the x5x swaps though.

The guys that helped me do my swap both have there's the way I said as well. Dom and Justin have done A LOT of these swaps and I trust them over you. Doesn't mean your not right but I will go with their experience.