M20B25 Swap

[4bimmers]

I have taken out a bad engine from an 89 325i and am replacing it with one from an 87 325i. So, I was chugging along thinking everything was compatible when I realized portions of the coolant system plumbing were different. The expansion tanks are on different sides of the engine, the radiator is different, the water pump on the earlier model has a hose that goes to the expansion tank and the later model doesn't. I guess all I can do now is swap the water pump for the later model. My question is whether the newer pump will mount up to the earlier engine block?

Now I'm wondering what else I am going to encounter that is not compatible.

[SpecM]

it all mounts up fine, but you need the late style pump, hoses, rad, res, and crossover tube.

but the pump bolts exactly the same way

[4bimmers]

re

I guess I am going to have to remove and replace timing belt to replace the water pump?

[SpecM]

IF its over 10,000 miles old, you should replace it any way

[peete]

I guess I am going to have to remove and replace timing belt to replace the water pump?

No.

[imwhyteyo]

does anyone know if you can use an early ETA radiator with an early m20b25 swap?.. i dont have the coolant res, or radiator from a swap ive just purchased.

[SpecM]

yes, all m20 radiators up to 87 are the same. Its not an eta/i thing

[MR 325]

yes, all m20 radiators up to 87 are the same. Its not an eta/i thing

Through 87 you mean. ;)

[livetheride]

does anyone know if you can use an early ETA radiator with an early m20b25 swap?.. i dont have the coolant res, or radiator from a swap ive just purchased.

If you have an early model car with all the early model cooling equipments, yes. I'm doing that right now :-D

If its a late model car and you wanna stick to the late model cooling system, then no. the inlet and outlet would be backward. you can use either radiator in any m20, but you just need the cooling system to match (i.e. bottle, hoses, waterpump).

[MattAvino]

This is sorta the info i was looking for. Im swapping an 88 m20 into an 87.

[jlevie]

Eiher cooling system can be used in either car. Since the radiators for the late cooling system are a little less expensive than the early variety, that is what I'd use on either vintage car if given a choice. The other issue between early (up through 8/87) and later (from 9/87) cars is the engine harness. You need to use the harness for the engine that came out of the car.