Radiator for M20 2.8 stroker

[thornado327i]

Hi all,

A radiator that was just fine for 2.7 eta-stroker seems not enough for 2.8. Yes, I do have an oil cooler, and no, it doesn't overheat totally. :)

Everything is fine when driving, trouble starts with at idle - few minutes of car just standing there with the motor running pushes the cooland temperature to 3/4 of the scale. It doesn't go any further fortunately, but then I haven't tried leaving the motor running at idle for longer than 10 minutes.

I heard radiators from E28 (M30 probably) fit and work fine... True?

Also - what's a better solution - new aftermarket or used original?

Any advice welcome.

[MR 325]

If it's heating up something else is wrong.

A friend is running a 2.8L M20 with OEM late model cooling system and has no issues. He is running an electric fan with no clutch fan and it almost never even turns on.

[thornado327i]

It's not overheating all that much. I have no issues when driving - even with some beating. A friend I bought the engine from was running it with a bigger radiator (but he's not sure what car was the radiator from) and had no issues at all...

When leaving the car at idle so that temp goes to 3/4 of the scale, and then starting to drive the temp goes to normal almost instantly...

[Wanganstyle]

use e36 radiator (aftermarket)

I used the radiator from my e36m, it was an aftermarket PWR unit. my m20 is the older style and it fit just fine with the e30 late model radiator mount.

used s54 water pipe junction and original m20 hoses + s52 (s50 euro) hoses

[thornado327i]

use e36 radiator (aftermarket)

I used the radiator from my e36m, it was an aftermarket PWR unit. my m20 is the older style and it fit just fine with the e30 late model radiator mount.

used s54 water pipe junction and original m20 hoses + s52 (s50 euro) hoses

Thanks for advice!

Any particular E36 model radiator i should look for? IDK whether 325i has a different one than 320i or 328i...

[Wanganstyle]

Thanks for advice!

Any particular E36 model radiator i should look for? IDK whether 325i has a different one than 320i or 328i...

stateside the twincam m50 family e36 all had same pn radiator as late model e30 m20's

mishimoto is popular for the cost but fit is 3.5/5 stars.

pwr is expensive and massive (15% larger than mishimoto)

depends really on whats avail to you, as shipping a rad (pwr is usa) from usa-> europe would be spendy!!!

[jlevie]

Since the engine temp is normal at speed, my first suspicion is that air flow at idle is insufficient. A bad fan clutch comes readily to mind. If the fan clutch has been deleted and replaced by an electric fan, that fan isn't big enough.

[nando]

2.8 10:1 M20 here.. stock radiator. No problems for the last 50-60k or so. Something else is wrong.

[mikeedler]

Since the engine temp is normal at speed, my first suspicion is that air flow at idle is insufficient. A bad fan clutch comes readily to mind. If the fan clutch has been deleted and replaced by an electric fan, that fan isn't big enough.

BINGO.

your problem has nothing to do with the radiator size.

[Wanganstyle]

yup. even with upgraded rad + dead clutch fan = overheating M20

[MR 325]

Like I said, you don't need a bigger radiator.

[thornado327i]

Sooo, took a closer look at the fan (not that I expected to SEE a bad clutch) and...

one spoke of the fan itself is broken! How the F did that happen?? Anyway, since it's easier to get a fan with a clutch than one without, I'll give it a shot before I get a radiator.

Thanks for all the advice everyone.

[jlevie]

A used fan isn't all that iffy a proposition, but a used fan clutch is a roll of the dice. Get a new fan clutch.

[bmwguy325is]

An E36 rad wont fit in an early model car BTW

[jlevie]

You can put an E36 radiator in an early car, but you have to use the late model expansion tank, water pump, and hoses.