Mishimoto E30/E36 Radiator upgrade from stock E30

[Jims5543]

Good day, I have a 1981 318i with a M50B28 swapped in.

Up until this point in its life it has had the stock E30 radiator in it. I am upgrading to the Mishimoto Aluminum 2 row with a Mishimoto aluminum expansion tank. I also have a Stewart Water pump, new hoses and new thermostat housing going in.

I have some questions before I start tearing the car down. The bottom of the expansion tank has 2 fittings. I see one hose going to the plastic expansion tank on the E30 radiator.

What is the second fitting for? Where does it go, I think it will go to the new radiator. I may be overthinking this entire deal.

Stock radiator



I realize the overflow hose by the radiator cap connects to the top of the expansion tank.



It seems obvious the smaller hose connected to the stock radiator connects to the nipple on the bottom of the tank. Then I have a threaded hole that is confusing me. I do not see what I am supposed to connect to it.




The radiator is also causing me some concerns.




I the passenger side of the stocker I have a coolant temp sensor. There is no bung for me to screw the sensor into.





I am really hesitating to dive into this project, I feel like I am going to get stuck. Right off the bat the radiator looks wrong to me.

[Jims5543]

Welp I found one problem, I was sent a 240SX radiator and not an E30/36 radiator.

Project aborted for now until proper radiator arrives.

[Jims5543]

I still need to sort out this expansion tank and what to do with the extra hole on the bottom.

Do I just plug it off?

I just pulled an image of a stock tank and it appears that I need a cap to put on it.

[BlackSpeed66]

I believe the threaded bung is for the coolant level sensor. My e34 has a similar expansion tank design and that’s where the level sensor goes.