DPAYNE21

This is a quick DIY for The Johnson CM30 heat exchanger upgrade. It took me about 1HR 30 Min with a lift.



1. Lift car or front of vehicle and secure safely.



2. Remove Front foremost undercover (6) 8mm coarse bolts



3. Factory Bosch pump is located on passenger side below frame rail as pictured.



4. Pinch/clamp the 2 hoses that supply and return cooling fluid.



5. Remove the 2 clamps holding the hoses to the pump



6. Remove the 10mm nut securing pump to car



7. Remove the electrical connector and vacuum hose from rear side of pump



8. Now you can remove the oddly shaped bracket in the pic by removing (3) 10mm bolts



9. Once bracket is off you can drill the 2 new(1/4") holes needed to secure the new Johnson bracket to factory piece. ( may want to use touch up paint so no bare metal to corrode.)

Hardware needed

(6mmx1.25).

-2 bolts 14mm long

-2 nut

-2 washers



10. At this point it is easier to go ahead and fit the CM30 to the bracket and fasten hardware to factory bracket.



11. Install Factory bracket/CM30 back into factory location



12. install the cooling lines(same as factory).



13. Cut the factory connector off and install your choice of connector. I soldered my connections, but if you plan to remove often for some reason a connector would work better. wiring is pretty self-explanatory but the colors are.



Factory colors Johnson colors

brown = ground/black

red/white = red/positive



14. I have plugged the vacuum line with 6mm bolt and used wire loom to protect the wiring.



15. replace factory undercover and check the coolant level/washer fluid and you’re ready to go

madmla21

Great write up this needs to be added to the DIY sticky at the top.

outrun

in. for when I have to do this someday...

dansamg

14. I have plugged the vacuum line with 6mm bolt and used wire loom to protect the wiring.

Great write up - I have mine on the way, so I'll be doing this soon.

Can you just give more detail about step 14 and did you bleed the system afterwords to get rid of any air pockets?

Thanks

thumper823

where's a good place to find one of these pumps? besides fleebay...

TopGun32

don't forget to bleed the bubbles from the system.

Near the supercharger clutch area, there is a small aluminum nipple with a rubber boot and clamp. Use a plastic hose, and place over the nipple and route the hose to your coolant reservoir.


start the car and let the system circulate the coolant to the reservoir.

The car needs to be warm for the pump to circulate, therefore do it after driving the car for a few minutes.

kamilclk430

Great Writeup thanks for looking out for those that wanna try this on by themselves

sir mike k

Hi DPayne21,

I want to attempt the same upgrade on a 2004 slk32amg and I need to know the following please :[1] when you say the cooling lines are the same as factory that you mean that the original rubber hoses match the inlet/outlets of the cm30 perfectly, ie they are both 20mm[3/4 inch] in diameter and [2] the vacuum line/hose that you plugged with a 6mm bolt as per para 14 refers to a line/hose that was affixed to the original OE Bosch pump as the cm30 does not have a vacuum line/hose fitting.....if affirmative, what was the purpose of this vacuum line/pipe in the original setup and if now disconnected/blocked/discarded will it not adversely affect the ECU`s reading of this specific cooling system ?

Kind regards from an old driver who is unable to afford MB agents outrageous charges where I live in South Africa.

sir mike k

Hi DPayne21,

When can I expect your response to my query of 01/10/20134 please ?...........this is the only thing holding me back from doing this upgrade.

Thamks,Mike.

SL65MONSTA

Do you know if the SL has a bleed valve to also do this?