Which radiator do you prefer?

[BenjaminButtton]

Thanks a ton Cyrix, I got it all hooked up last night!

I'm going to need a longer small hose at some point to mount the tank how I like it, but that can wait until I get the damn thing running (didn't start).

[Cyrix2k]

Gotcha, so you just removed the tank from its attachment point and have it kinda hanging there off to the side?

exactly, just make sure the tank is the high point in the system. The only hose that goes to the radiator is the very small one that runs to the cap of the expansion tank. The hose that goes to the bottom of the expansion tank comes off the spiderweb hose under the intake manifold - I think the comparable hose on the m20 ran to the water pump. This one does too, but the access is from behind the water pump - tee the line between the head/heatercore & water pump if you need to. That's also why I wrote that the tank is really just an overflow tank above - once the system is filled & bled, it really only is an overflow tank. BMW just has a weird way of doing things.

[BenjaminButtton]

Gotcha, so you just removed the tank from its attachment point and have it kinda hanging there off to the side?

[Cyrix2k]

I have the expansion tank off my e36 radiator with the tank to the side. You should be able to run the e30 expansion expansion tank - the early e30 one works for sure, I don't know about the late model.

[BenjaminButtton]

You guys that are running the e36 radiators, did you modify anything to make them fit..? I was sliding my '95 325i radiator into the car last night and the expansion tank hits the valve cover... If I took the black plastic fairing deal for the fan off or modified it I could maybe make it work. Maybe relocate the expansion tank?

Otherwise I'll just use the m20 rad, I just want to avoid that since the overflow tank is kinda fugly :)

[turbo325i]

ok, fair enough. It would be easy enough to come up with a solution though.

Oh it would? feel free to share the solution. For now I have the expansion bottle back on it. but would like to do something different.

[Cyrix2k]

No, its not. The difference between an expansion tank and an overflow is the expansion tank is pressurized with the cooling system and has the radiator cap built into it. there is NO radiator cap on the radiator itself.

An overflow is the older style where the radiator cap that holds pressure is on the actual radiator and the overflow tank is NOT pressuized, but allows for coolant to exit the radiator and enter again when the engine warms and cools.

:)

ok, fair enough. It would be easy enough to come up with a solution though.

[turbo325i]

uhhh... the e36 radiator is exactly that. An "expansion" tank is just another way to word "overflow" tank. I have my e36 radiator in the '85 with an overflow tank to the side.

No, its not. The difference between an expansion tank and an overflow is the expansion tank is pressurized with the cooling system and has the radiator cap built into it. there is NO radiator cap on the radiator itself.

An overflow is the older style where the radiator cap that holds pressure is on the actual radiator and the overflow tank is NOT pressuized, but allows for coolant to exit the radiator and enter again when the engine warms and cools.

:)

[Cyrix2k]

Ok, so here is what I figured out. The e36 radiator will fit(by and RCH) and thats all good. but the expansion bottle will not fit on the right hand side of the radiator... the 318 radiator has the expansion tank on the other side where there is tons of room, but by design the tank interferes with the fan... :( I just want a clean bay with no tank on the fenders ya know...

I wonder if there is a regular radiator out there, with just a cap on top that i could run a overflow with?

uhhh... the e36 radiator is exactly that. An "expansion" tank is just another way to word "overflow" tank. I have my e36 radiator in the '85 with an overflow tank to the side.

[turbo325i]

Ok, so here is what I figured out. The e36 radiator will fit(by and RCH) and thats all good. but the expansion bottle will not fit on the right hand side of the radiator... the 318 radiator has the expansion tank on the other side where there is tons of room, but by design the tank interferes with the fan... :( I just want a clean bay with no tank on the fenders ya know...

I wonder if there is a regular radiator out there, with just a cap on top that i could run a overflow with?

[butters]

+1 for a 6-cyl radiator.

I kept my M42 in there and in 75-80+ degree weather I cannot drive without constantly eyeing the temp gauge. When driving with enough speed it's okay, but at a stop even with the 16" puller the needle creeps past 12 o'clock. After rebuilding the engine, I will not continue to put it at risk.

One other tidbit - no matter what thermostat you use, your radiator has a limit of thermal capacity; the thermostat sets your operating temperature, but once it's hot out and/or you push the car hard, the thermostat is wide open (assuming it works) and the problem arises when your engine is generating more heat than your radiator can transfer to the air passing through it. If you have an 80C t-stat or a 90C t-stat (I forget what the actual choices are) and your engine is beyond 90C, the thermostat is out of the equation and in either case it's up to the radiator to determine the running temp.

I have an E36 radiator to go in before it gets too hot again. I've tried researching whether the SPAL slim puller will still fit, and there isn't a clear consensus or story of someone trying that I have heard, although most say no. I'll give it a shot before I pull out the condenser and mount it as a pusher.

Does anyone run a 6-cyl radiator with a slim puller?

[BenjaminButtton]

Well that makes me :(. Electric fans are great. I just like to keep it simple when I can, and I love mech fans...

Are you running the e36 fan? As Cyrix said the e36 fans are bigger - use the m20 (or m42 - I would imagine the dimensions are the same although if I recall correctly the blade count is different).

[e30austin]

Every 24v I've done used a late M20 radiator and expansion tank. On both of my cars, I used the stock AC fan and wired it up to work using the stock A/C switch.

Tried an M42 radiator on my buddy's S52 car and had nothing but issues with it. Switched to a late M20 radiator and it worked perfect.

[turbo325i]

I'm pretty sure the mechanical fan will clear the end tanks of the e36 radiator, but you can't run a stock fan - it's too thick and hits the radiator.

Well that makes me :(. Electric fans are great. I just like to keep it simple when I can, and I love mech fans...

[Cyrix2k]

I know I can search, but i dont have time right now. So I have the motor in the car now, and the only problem with the m42 rad. is the mech fan contacts the plastic side tank on the driver side. It wont work. Is the e36 going to give me the same issue? I hopefully will have an e36 rad later but was wondering if someone could tell me sooner?

Thanks guys.

I'm pretty sure the mechanical fan will clear the end tanks of the e36 radiator, but you can't run a stock fan - it's too thick and hits the radiator.