Submitted by: Zatman, Roadfly Member
Note: This may not apply to the V12 engine which is a lot more time consuming as it requires taking off a number of additional components to allow enough room for the radiator to come out.
Disclaimer: This is an account of my experience with replacing the radiator on my car – a 1995 840 Ci auto. Use at your own risk and exercise caution when following. Many opportunities exist to get back & eye injuries, poisoned, burnt, scratched, cut and bruised if you are not careful.
Time needed: 2.5 hours (careful & easy pace) – No lift required.
Tools needed:
1. Screw drivers
a. Phillips (+): Small, medium and large will do
b. Flat blade ( – ) ; small
2. Socket 1/4” or 1/8”
3. Short socket extension
4. Socket 8 mm
5. PTFE tape
6. Large tray to catch the coolant (I used aluminum disposable food trays from Target)
7. A bucket to put the waste coolant in temporarily
8. Some clean non-abrasive cloth to cover the headlight covers
9. Household gloves
10. General rags to mop up. Its gets messy no matter what you do.
11. Kitchen roll (absorbent strong paper)
12. Watering can or a water hose
Spares:
1. Radiator
2. Coolant neat (not the premixed version) 2 US gallons (7.6L) (I used Prestone)
3. Distilled water 2 US gallons (7.6L)
4. Expansion tank (Optional – highly recommended if you have the old style two color black/yellow tank – don’t forget 1 extra small size hose clip)
5. Radiator Cap (Optional – highly recommended if your cap doesn’t say 200 on the inside)
6. Plastic bleed screw (Optional – recommended)
7. Hose clips (Optional – 2 large, 1 medium & 1 small)
8. Hoses (Optional on condition – don’t forget the extra clips on the engine side if you decide on replacing the hoses)
9. Temperature sensor (Optional – There are two kinds available each switching at different temperatures. You only need one.)
10. Plastic clips for the air duct shroud (Optional – in case you break some when removing)
Procedure:
1. Work on a cold engine (don’t get burned). (Stretching exercises before starting also help prevent back injuries)
2. Open the hood/bonnet and cover the pop-up lights with soft cloth. You might also want to cover the front wings /fenders.
3. Remove the central plastic air duct cover by turning the 6 small plastic clips so that the – signs are parallel to the sides (¼ turn) and inserting a small flat bladed screwdriver into the three clips at the top.
These are the middle three arrows on the picture. Lift up and back to clear the front tongues.
4. You should now see all the radiators lined up one behind another. The engine radiator is the one at the back with its top hidden under the plastic fan shroud. The smaller vertical radiator attached to it with the screws is the automatic transmission cooler.
5. Remove the radiator cap (It’s on the expansion tank). Ensure the engine is cold or you might get a face full of steam = not nice.
6. Underneath the car. Remove the lower air spoiler by unscrewing all the screws and pushing towards the back (& slightly down) to release the hidden catches. (Don’t forget the 2 middle screws and the plastic clips in addition to the 3 screws on each side)
7. Underneath the car. Remove the engine splashguard that is protecting the front end of the engine. Both steps 6 & 7 are not essential but help a lot with draining and catching the coolant.
In the following text # followed by a number is referring to the numbers on this diagram.
8. Underneath the car. Loosen the radiator drain plastic bolt (#2) with a large screwdriver so you don’t destroy the plastic. Don’t completely undo it yet. Get out from under the car. Replace the radiator cap and place a tray underneath the radiator drain. Reach underneath with a gloved hand and slowly unscrew the plastic bolt. Fluid will start coming out. When the coolant stream slows down remove the radiator cap and loosen the bleed valve. Let the radiator drain fully. Very little of the 13.5 liters (3.45 US gallons) comes out of the radiator (about 2 liters). Replace the drain screw and hand tighten. Empty the coolant into a bucket and reposition the tray below the expansion tank.
9. Remove the two plastic pieces (#9) at either end that are holding the radiator down by unscrewing the M8 (8mm) bolts (#12). Note that the design allows the radiator to move slightly and thus relieve stress even when the bolts are fully tightened. Use a socket extension to avoid hitting the light covers.
10. Unclip the fan shroud from the side air duct guides by using a flat screwdriver to release the clips. (the outer four arrows in the picture at the top). Use a small flat screwdriver to draw back the pin (#14) that is in the expanding rivets holding the top of the fan shroud to the radiator. With both pins removed, pull back and remove the expanding rivet where the pins were placed. You might need to coax it to come out.
11. Unscrew the small hose from the upper right (looking towards the back of the car) of the radiator.
12. Loosen the expansion tank bottom hose clip and move it towards the back. Reach in and unclip the large bottom radiator hose. Don’t pull the hose away from the radiator yet. (Depending on the position of the screw it might be easier to unscrew from under the car)
13. With a gloved hand slowly pull the expansion tank bottom hose back. Most of the coolant will come out now so you may need to hold the hose to control the flow rate so it goes in the tray and not all over the place. Some will spill – use some rags.
14. Empty the coolant into the bucket as necessary. Unclip the large top radiator hose and remove hose from the radiator. Remove the bottom radiator hose and catch the coolant in the tray. Allow to drain fully. You are unlikely to get every last drop of the coolant out. I got about 11-12 liters.
15. Stuff the expansion tank bottom hole with some paper to avoid drips.
16. Carefully lift the fan shroud with the expansion tank attached. It comes straight up and the small movement with the loose radiator is enough to let it come out without removing the fan.
17. Top of the radiator is now fully visible with the top two M8 (8mm) bolts holding the transmission radiator in place visible.
18. Look to the left side (looking towards the back of the car) of the radiator. There is a temperature sensor here (#5). Remove the electrical cable clip. (You might need to loosen the sensor slightly so it turns the cable clip upwards to make it easier.) Unscrew and remove the sensor.
19. Lift the radiator up a little with the transmission radiator attached. (Get help to avoid back strain) You will only be able to lift a couple of inches as the transmission radiator hoses start hitting the bottom of the fan. Reach down into the side of the radiator and remove the rubber foot (#8) from each side by pulling them downwards. Now you will find that you can lift the radiator slightly and push it back next to the fan. This will give you several inches of working room to remove the bottom two 8mm bolts holding the transmission radiator in place.
20. Remove the top & bottom bolts holding the transmission radiator. One of the bottom bolts will not be visible. Feel for it. The bolts are not highly torqued and come off easily. Take your time.
21. Lift the radiator straight up and out. You will see dish shaped retaining pads (#6 & #7) where the rubber feet rest.
22. From the old radiator remove the female clips (body nuts) for the transmission radiator bolts and the small rubber piece at the top of the radiator that protects the small hose from the expansion tank to the top of the radiator from chafing on the radiator metal. Place all in the same position on the new radiator. This is also a perfect opportunity to clean the area from where the radiator came out and check other hoses, connections and other fittings in this area.
23. Drop the new radiator into place next to the fan.
24. Re-attach the transmission radiator.
25. The Trickiest Step – Lift up the radiator and replace the rubber feet (#8) and drop onto the retaining pads. The pads are quite loose so be careful that they don’t move out of position and drop into an air duct or you’ll be going fishing. Additional pair of hands are useful
26. Replace the temperature sensor. I used some Teflon tape at the back of the washer to ensure a seal. Tighten and attach the cable.
27. Replace the fan shroud with the expansion tank attached. Make sure the tongues on the shroud engage in their counterparts on the radiator. (You do not want the shroud to hit the fan.) Also make sure the top small hose from the expansion tank to the top of the radiator is lying in top radiator channel and is not getting pinched. Ensure that where it moves back towards the shroud it lies over the rubber covered part of the radiator. See E31 FAQ for an excellent “How To” on expansion tank replacement. If you are going to change the expansion tank then do it while the fan shroud is outside the car – it’s so much easier!
28. Re-attach all hoses and secure with clips.
29. Remove the bleed screw from the expansion tank.
30. Fill with 1.75 US gallons (6.6L) of neat coolant. Now you have the minimum correct amount (50%) of coolant in the system. (I added almost 1.9 US gallons (7.2L) as some coolant is lost when bleeding the system. Top off & bleed with distilled water. You will need to do this whole step slowly. Take your time.
31. You won’t be able to add all of the coolant without starting the engine but don’t do it yet. Replace the bleed screw and the radiator cap and using a garden hose or a watering can thoroughly wash the whole area around the radiator. You want to dilute off and remove as much of the spilled coolant as possible so use lots of water.
32. Underneath the car. Replace the bottom plastic engine splash guard and the lower front spoiler.
33. Ensure all hose clips are tight.
34. Replace the middle air duct cover.
35. Follow the radiator bleeding procedures in the handbook and elsewhere on the Roadfly posts.
36. Inspect for leaks.
