Transplanting a BMW cross flow Aluminum radiator in my 280Z

[BuDavid]

hi folks!

I just finished a hard time changing the head gasket + intake-exhaust gasket.. and in the same time an experiment that I thaught of for a long time..

I took my car to my friend to replace my old ugly copper radiator which was leaking from eveywhere! (that I discovered when I saw it from the hidden side from the front)!

I put into it an aluminum radiator from a BMW 325i 1995, and guess what, this is a two row radiator and fits really good, we needed to use a plate with about 3 inches to attach the bushing mount, the upper part is held with original BMW clamps of the radiator:)

we needed to modify an L shape pipe with a filling cap, guess what, it is even in a better position than the previous one on top of the radiator, because it is at the gighest point right now.. I removed the thermostat that I had before 82C with a new one of 76C.. removed the clutch fan and put a two speed electric fan which can be driven directly at first speed and the second can be an addition depending on a Temp. switch mounted on the radiator itself ..

I'm very satisfied until now, but I'm curoius about the situation in the summer with the A/C on, right now, the heat dessipation is very good coz it is a corss flow radiator and when I touch the colder side, it is very cool relatively to the previous one.

I would like to have a bigger/slimmer fan with bigger shrowd to force the cooling arround the whole area of the radiator, but didnt find a proper sized fan yet!

cheers!

[zbane]

Excellent job, Mohamed! At least you can drive around without worrying about cooking the motor, and you still have time to search for the larger fan-or figure out how to keep both fans on all the time.

[Victor Laury]

Mohamed, Post photos PLEASE!

[e_racer1999]

Mohamed, Post photos PLEASE!

QFT

this sounds like a great idea!

[BuDavid]

sorry for being so late, I was busy with the 4 U-JOINTS I distroyed in my 300ZX Z32:stupid:

anywayz..

the combination is like this:

-radiator of BMW325i 1988-1994 (they vary only with the transmission cooler at the side)

-upper hose of 325i 1991

-lower hose of 535i 1990

-brackets of 525i 1988 (if I'm not mistaken')

-strong plate to support the radiator's bushings seat for the left side ( I choosed left side to give space for the AFM and the condencer pipe..

ok let's start over..

pic #1:

the first picture shows the overall result with some details (I hope they will be fine)

pic. #2:

in the second picture we see the top view of the upper hose, notice that the flange of the radiator is bigger than the L-Pipe and the thermostat flange..

pic. #3:

the lower hose form the 535i.

pic#4,5 and 6 show the lower seats of the radiator the left one is attached to a plate to reach the radiator from the body frame, it is just a plate wit holes to screw them with the body and a screw to hold the radiator's seat, while the right side the seat can be directly mounted on the frame with one screw (it will hurt when making holes in the frame):hurt:

note that the 6th pic is from behind the alternator to show the right side mount through..

pic. #7 and 8 show the upper brackets from the 1990 BMW 525i the difference between the one that has bushing and without, they fit perfectly as if the were originals, the folding of the metal is exactly the same as it is in the BMW!

pic. #9:

the clearance between the 2 speed elec. fan and the pullies.. I'll get a nicer fan, I don't like this one. I'll make the second speed optional with the Temp sensor at 80C

pic.#10:

the secret path of the fans wire:)

and I changed the Thermostat to 76C because the 82C was closing and opening too much, which caused unstability of the temp.. the radiator cools so much I guess:smoke: the 76C mainatained better because it opens faste which matches the heat exchange at the radiator..

we tried to make the fan stop and run depending on the Temp. but it didn't work because the sensor at the rariator gives different response than the Temp sensor of the dashboard gauge..

but I have to wait until summer comes so I will see the real ability of heat exchange at 54C!! this is the challenge with the A/C on!

feel free to ask.. I'm here for you guys even if can't be here so much temporarely..

forgive my gramatical mistakes.. coz I'm in a bg hurry and I like to give the best help here..

wish me good luck in fixing/selling my Z32 to afford the price of a very clean 1977 280Z with centerline wheels!! I'm done from that car!!

bye for now...

[Arne]

Hmm. Same radiator my '96 328i uses, all six cylinder E36 '92-98. Easily available, and not too expensive. New ones can be found for less than $175 online, probably about the same from local shops without the shipping.

BUT...

The radiators out of those E36 models have a well deserved reputation for the upper plastic neck cracking. I've had to replace mine once already, they frequently seem to fail after 5-7 years.

So it's definitely an option, but maybe not as durable long-term as an OE type one. But probably much easier to find in some parts of the world.

[viparz]

Definitely let us know how your car goes in your hot summers.......Time and temperature will tell if this relatively simple transplant will reap many cool rewards.

[BuDavid]

Arne, which p[lastic neck crack after time?? I didn't understand you very well.. but if you were referring to the brackets on top, they are very cheap and it wont bother me if they'll crack after 5 years from now.. if I got you right thugh..

but on the other hand, let us see the positive points, Aluminum radiator is more effecient than copper and more compact in "our case" ..

and the best thing about the horizontal flow is than if you get some accumulation of dirt and rust at the bottom of the radiator you will loose the lower lines one by one, but in the vertical flow as with the OE radiator you get them all chocked at once..

but anyway, I'm waiting for your reply Arne, I need to know what will happen to be prepared:) thanks..

Viparz..

to let you know you'll have to wait until August;) by that time I'm sure that I'll forget this post completely:)

cheers..

[ph240]

The BMW rad will fit a 6-87 to 1991 BMW E30 M 20 engine w/ manual trans and a E36 6 cylinder car from 1992 to 1999 both man & auto trans cars.

Use caution as the upper rad hose neck will break off without any warning around 60K miles of use. I woulkd recommend a new one and forget about a used one..to risky.

[BuDavid]

thanks for the advise man, but if you say about 60k mil of use.. it looks fair enough to me since I take the baby on tour once a week:classic:

anywayz, I agree on using new stuff when we talk about rubber and plastic, but at that time, I fitted "used" metal part sych as the radiator, but the upper hose is brand new bro..

I'll try to modify the fan speed operation (temperature dependance) since the hot weather is coming, because I don't want to keep the fan ON always.. and BTW the temp. shooted up yesterday above 3/4 of the gauge, but I think that the Thermostatic valve got stuck, coz it ran then at higher temperatures with A/C on, probably 38 degrees.. so far so good,I'm waiting for the real challenge (AUGUST):dead: