Bigger radiator

[driftwood]

I want to fit a bigger radiator to my manual facelift 325i. A tropical radiator apparently drops straight in but 2nd hand ones are rare and if a new one is available from BMW it'll probably be very expensive. What are my choices? I don't mind a bit of modifying (I'm no purist) but I'd prefer something that just bolts in. Also, is it worth upgrading the oil cooler or is the standard item adequate?

[daimlerman]

Why do you need a bigger radiator?
The things cool perfectly well if in good condition,and a radiator really should be a 100k mile service item.

Oil cooler is not needed these days,a modern oil is better for the engine and allows quicker warm up times when the oil cooler is removed from the circuit.I have run a 2.7 M20 for years with no oil cooler and no problems.

[driftwood]

You're probably right and I won't have cooling problems with the standard radiator but one of the things I'll be (eventually) using the car for is drifting and there's not a lot of air flowing through the radiator when going sideways. The car came with an electric fan and I'll be fitting an override switch so it can run constantly.

[Grrrmachine]

Buying a second-hand radiator is akin to second-hand underwear...

You can buy decent brands of radiator such as Nissens for a lot less than BMW will charge for the same unit. I picked up my tropical rad for sixty quid, but UK prices might be a little bit higher.

If the car's for "diffin" then by all means fit an electric fan, but do it properly with a built-in temp switch - don't waste your time with a manual switch because you WILL forget one day and you WILL kill your engine:

http://www.e30zone.net/e30zonewiki/inde ... ectric_Fan

[jmc330i]

325i 'aircon' rad. Same thickness as a standard rad, but is taller (hangs lower down). Will drop straight in, even using your existing hoses. You will just need to cut the upper hole in the front valance so air can get to the bottom of the rad.

[driftwood]

Grrrmachine, I have a built-in temp switch already. It came fitted along with the electric fan by the previous owner. I just want to add an override switch as a preemptive strike but yes, just fitting an on off switch to the dashboard would definitely be asking for trouble! James, according to a plate riveted in the engine bay my car had air-con fitted but I don't think it was fitted at the factory and I don't know if an air-con radiator was fitted during the conversion. The air-con was removed before I bought the car. Any idea of the dimensions of the radiators?

[jmc330i]

I don't have the sizes, but the pic below is a 325i aircon rad (ignore the arrows, its an old pic).
The bottom of a non aircon rad is just below bottom hose, this rad extends down a few inches to behind the lower front valance....

[driftwood]

Thanks. E30 325i air-con radiator now on my shopping list.

[hongkongfuey]

Take the rad out. Take out the plastic cowling . Put in an electric fan. Put the switch from e30 air con onto the thermostat housing instead of the rad as it cools when the engine is hot not just the rad . That's how mine is set up. If you need more cooling some holes in the front valence

[Brianmoooore]

Take the rad out. Take out the plastic cowling . Put in an electric fan. Put the switch from e30 air con onto the thermostat housing instead of the rad as it cools when the engine is hot not just the rad . That's how mine is set up. If you need more cooling some holes in the front valence

That's just wasting a significant amount of power/fuel. The radiators job is to provide a supply of water below engine working temperature that can be blended into the engine's coolant jacket by the engine coolant thermostat. The electric thermostat's job is to turn on a fan to cool the water in the radiator when its temperature begins to rise towards engine running temperature, as a result of insufficient airflow from other means. This is why BMW placed it in the ideal position, part way down the 'hot' side of the radiator.

[hongkongfuey]

Not at all and its safer. If there is a leak in the rad and the temp switch doesn't get touched by water the fan won't come on. Mine comes on when it needs to and its generally in traffic.

[Brianmoooore]

If there's no water in the radiator, I don't think its going to make much difference whether the fan switches on or no, since it won't have anything to cool!
Electric fans don't run for free - the load on the alternator is paid for in both available engine power and fuel consumption.