BMW 3-Series E36 radiator swap

Is the radiator in your E36 or Z3 leaking? Replacing it is easy and inexpensive, as Andrew Everett demonstrates.

The coolant level was dropping on my 1997 318i Touring – not a massive amount, but enough to require a top-up every week. This could have been due to a pinholed hose or even the beginnings of head gasket trouble, but I noticed that it was leaving traces of antifreeze on the drive and there were droplets on the base of the radiator, a unit that was bought secondhand five or six years ago, so could be up to a decade old. Luckily, I had a spare Nissens radiator from a written-off 318i, complete with the fan. I’ve always used Nissens rads and don’t really trust anything else apart from pricey main dealer parts.

The E36 radiator has a built-in expansion tank and proper hoses with Jubilee-type clips. It’s so well designed

that my personal record for replacing one is just 19 minutes on a 318is, including bleeding it.

There are a couple of different rad types: a deep one for air-conditioned cars (see Photo 8) and a shallow one for the rest. The E36 rads have 440mm cores and while the four- and sixcylinder rads can have different part numbers, they all seem to interchange OK despite a slight difference in core thickness for certain climates. The four-cylinder E36 rad also fits the 1987-1992 E30 and the six-cylinder rad fits the E30 318is and E34 520i and 525i.

New Nissens radiators can be bought online from £60 for a shallow fourcylinder unit to just over £100 for a deep six-cylinder one. Coolant capacities are 6.5 litres for the four-cylinder and 10.5 litres for the six-cylinder; antifreeze capacity should be 40% of these figures.

When the job is done, clean up any spilled coolant with clean water, washingup liquid and a broom, as antifreeze contains glycol that is toxic to wildlife.