Call any BMW dealer and give them your VIN. They'll be able to tell you which engine you have under the bonnet.

By the way, It's a M20 B20 Motronic (129 bhp).

 

which engine is the m20 motronic? The 1990 or the 1987?

 

The M20 Motronic came after 09/1985.

 

so why would the two years have different water pumps? The one I had on the car has one pipe, with a secondary pipe coming off it. The one that I got from the dealer had only one pipe, no secondary pipe coming off it. How do I know for sure that my engine is what I have been thinking it is?

 

so why would the two years have different water pumps? The one I had on the car has one pipe, with a secondary pipe coming off it. The one that I got from the dealer had only one pipe, no secondary pipe coming off it. How do I know for sure that my engine is what I have been thinking it is?

I am not familiar with the M20 engines, but as I've written above, call a BMW dealer and give your VIN. They'll look it at the Electronic Parts Catalog and will be able to tell you what engine and the correct part number for the water pump.

 

Well, I have been having water pump problems. So today I thought "lets rip out the old one, and go and get us a new one" So I did so. BUT......... when I went to get the part, I saw that the one offered to me is in fact NOT the part I wanted. So I showed the guy at the shop my destroyed waterpump. He looked it up on his system by part number etc, and it turns out that my pump is in fact for a 1990 320i. Now I have my car registered as a 1987 320i. As far as I know, the car has not had any engine swaps. How do I go about telling what engine I am running?? Any clues!? Thanks.

Go to http://www.bmw-z1.com/VIN/VINdecode-e.cgi and type in the last seven digits of your VIN. When you get the results of the search, come back here and guaranteed someone will quickly be able to tell you what engine you have.