M42 radiator swap complete!

[Naplm00]

Ill have some pics up soon but, for thoes who have completed this swap with a M20...

What did you use for your upper rad hose? I found one at a local auto parts store that kinda fits but it is semi-collapsed

and direct or near direct fitments?

[Streichholzschächtelchen]

It's probably a stupid question but what is the purpose of swapping an m42 radiator into an m20 car?

[xwill112x]

integrated resevoir

[browntown]

Can't contribute technical help, but I can demand pics/

[Streichholzschächtelchen]

integrated resevoir

Thanks you! That'd actually be quite nice to have if I were shaving my engine bay lol. Everything else is removed anyways.

[xwill112x]

Thanks you! That'd actually be quite nice to have if I were shaving my engine bay lol. Everything else is removed anyways.

it's less coolant hoses/connections to go bad and leak as well. great mod imo.

[rThor432]

I never took pictures of my M42 radiator after I installed it.. wish I had. That would have been nice for documentation.

[Jand3rson]

Yes, yes, pics and info! Also, do you have a late or early model car? I have an '86 325es, so if you have a late, I'll have to do it a little differently.

[SpecM]

snap a few pics of the hose with different angles, I'll flip through my Gates book tomorrow and see what I can do

what hose did you use? part #? oem or Gates/Dayco?

[Naplm00]

integrated resevoir

ding ding correct

[Naplm00]

snap a few pics of the hose with different angles, I'll flip through my Gates book tomorrow and see what I can do

what hose did you use? part #? oem or Gates/Dayco?

Not sure, ill check the hose tomorrow

Yes, yes, pics and info! Also, do you have a late or early model car? I have an '86 325es, so if you have a late, I'll have to do it a little differently.

Ive got a late model cooling system, I did a Timing belt, Waterpump, manual steering swap and oil pan at the same time.

For an early system, the only difference would be running a new hose form the second outlet of the water pump (circut #10) to the inlet on the new res. Pain in the ass, i think. May be cleaner to swap to a late model pump then use a "T" on hose #18 in this pic




then this way you dont need to run another hose across the front of the engine , you would most likely also have to swap to the late model lower rad hose setup since on the early model the lower rad hose inlet is on the opposite side of the rad then the inlet on the M42 rad.


Ill be posting a complete write up with wiring and everything for both models after i put in my electric fan this week with some pics of my insanely disgusting engine bay..you will understnad why i swapped to non-power steering.

[Naplm00]

just a note to all who want to do this before the write up, the system is very hard to bleed

I had to jack up the front left corner of the car, and pour the coolant down the upper rad hose, then use a spare hose and blow into the rad res to force the air out of the top of the system, it then bled properly...using both bleeder screws at once

[Jand3rson]

I probably would just swap to the late model water pump. I'm pretty sure that will swap directly over, right?

[Naplm00]

I probably would just swap to the late model water pump. I'm pretty sure that will swap directly over, right?

Yep, with no issues, the block mounting points are exactly the same.


I just took off a early model pump form my late model cooling system. My WP failed and i had no cash for parts..the yards around me only had etas with the early system...so i plugged the outlet with a pipe plug and silicone and ran it for nearly a year.

[Naplm00]

snap a few pics of the hose with different angles, I'll flip through my Gates book tomorrow and see what I can do

what hose did you use? part #? oem or Gates/Dayco?

I dont have the hose part # i used..just piced it off the shelf at autozone

it is marked: "AU 16709 C"

THe issue is the part of the hose that connects to the thermostat housing. Oo the original M20 hose it has a sharp turn at a funny angle down towards the driver side wheel well..it is hard to find a hose like this with a S bend.


In auctuality the stock M20 hose would be a perfect fit if the lower part of the hose that connects to the rad made its turn to the front of the car about 2-3 inches sooner. Its just a tad too long. The original M20 hose end ends up right under the rad cap in the center of the new resivior.







you can see the zip tie i put on the upper part of the hose to keep it from fully collapsing