What's the *best* radiator for M50?

[Fusion]

Got it mounted, got some junkyard hoses, filled up and came across a new "problem".
I got the M42 rad without a cap, and thought that the old one would fit, they look the same. Problem is when I screw the cap on, tight enough and press the upper hose, I can hear it breathing through there (bleeder screw is tight).
Are the caps diffent in some way or am I just missing a gasket? I don't think the cap has one, though it sealed fine on the old exp. tank.

Oh and there's a 1.4 or 2.0 bar cap. Which one is adequate?

[Fusion]

Checked everything I could in the parts catalogs and the only difference is the pressure rating.
Why is 318is exp. tank 1.4bar and 325i exp. tank 2.0bar?

[FredK]

By increasing the cap pressure, and therefore cooling system pressure, the heat capacity of the cooling system is increased. The M42 outputs less power, and most likely does not throw out as much heat as an M5x. That's probably why the M42 has a 1.4 bar cap, and the M20 and M50 have 2.0 bar caps.

The Euro E34 525i actually shared the same 440mm radiator as found in the 318is, but used a 2.0 bar radiator cap. So, you'll want to also use a 2.0 bar cap on your car.

[nando]

For this reason. BMW plastic end tanks and the overflow tanks attached to the radiator(E36 type garbage) are known failure points.

The aluminum radiator removes part of that equation and is larger and sits right on the OEM Mounts. There is a little extra plumbing but well worth it. I have see some nasty ass overflow tanks in the E28 and E30 cars but I personally have never had a failure or had to fix one. They just seem of higher quality.

I've seen a lot of E30 radiators that were original 20+ years old / 200k+ miles and didn't have any problems with the plastic end tanks.. it's not the E30's fault that the E36 is a pile of shit. :p

[Fusion]

The whole problem was that the gaskets on the old cap were used/hard/squished.
Bought a new 2bar cap, no more breathing and I'll report back on how it all works.

[dude8383]

The whole problem was that the gaskets on the old cap were used/hard/squished.
Bought a new 2bar cap, no more breathing and I'll report back on how it all works.

Hey do you have the p/n for the 2bar cap? Realoem is showing me the 1.4bar for the 325i...

http://www.realoem.com/bmw/showparts...06&hg=17&fg=05

Wut???

[Jand3rson]

it's not the E30's fault that the E36 is a pile of shit. :p

That might need to go in my sig with the other quote...

[Jand3rson]

That's the bleeder. You may have a tough time getting a new bleeder screw to thread in there and seal properly, unless you can get all of that crap out without damaging the plastic threads.

So I got the rest of that epoxy shit out of there today, had to drill it out. But also realized something bad, there's a crack in the little neck where the bleeder screw threads in, that barely extends into the rest of the plastic housing at the top of the radiator. Also, when I finally chipped out the last of the epoxy that was down in the hole, a piece of something broke off inside the filler neck hole, and I don't know if it's a piece of epoxy, or an actual part of the radiator itself, but it looks like I might not be able to use this radiator after all, might just have to get a new one.

[Fusion]

Hey do you have the p/n for the 2bar cap? Realoem is showing me the 1.4bar for the 325i...

http://www.realoem.com/bmw/showparts...06&hg=17&fg=05

Wut???

Should be 17 11 1 742 231

[dude8383]

By increasing the cap pressure, and therefore cooling system pressure, the heat capacity of the cooling system is increased. The M42 outputs less power, and most likely does not throw out as much heat as an M5x. That's probably why the M42 has a 1.4 bar cap, and the M20 and M50 have 2.0 bar caps.

The Euro E34 525i actually shared the same 440mm radiator as found in the 318is, but used a 2.0 bar radiator cap. So, you'll want to also use a 2.0 bar cap on your car.

Should be 17 11 1 742 231

Thanks Fusion!

According to that part number its for the M42...

http://www.realoem.com/bmw/showparts...17&fg=05&hl=20

Why would the M42 have a higher rating?

[Fusion]

Just got back from track day, all is fine, temp needle stays right before 1/2.
I do think that the hoses are harder with the 2.0 bar cap, that makes sense.
The valves chattered again after the 25mins, I think I need to work out the oil cooler during the winter.

[dude8383]

Just got back from track day, all is fine, temp needle stays right before 1/2.
I do think that the hoses are harder with the 2.0 bar cap, that makes sense.
The valves chattered again after the 25mins, I think I need to work out the oil cooler during the winter.

I gotta check my cap, I don't remember whether or not I pulled it off of my m42 radiator.

Good to know though...

[dreamchasin]

m50 radiator does me fine.

[Gnarles]

I gotta check my cap, I don't remember whether or not I pulled it off of my m42 radiator.

Good to know though...

I checked the cap on my 325i last night and I have a 1.4 bar cap as well.

[MacBudd541]

When using the m42 radiator, which hoses do you use? I'm having a hard time finding an upper hose that works.