engine and drivetrain How To Change Your Radiator And Cooling Fan (And What Not To Do)

[Andrew Havens]

So this is going to be part "how to" and part "help!" because it didn't end up how I hoped it would. Please read through and see if I did anything wrong, or how you would have done it differently.

 

My cooling fan needing to be replaced. I had never drained and replaced a radiator before, and the few Haynes manual black and white pictures weren't much help. It probably took me 4-5 hours to do this job which should have taken less. I took as many pictures as I could in order to help the next person. I also don't have jack stands yet, so I did all of this with the car on the ground.

 

Step 1: Drain the radiator

 

Take off the radiator cap. You may need to push down as you twist.

 

 

The Haynes manual said to "move the heater control on the facia to HOT". I'm not sure what a "facia" is, so I skipped that step.

 

Put your drip pan under the car. I wasn't sure how much coolant would come out, so I bought a 5 gallon drip pan. It was almost too tall, and a lot less than 5 gallons came out (maybe 1.5 gallons). Make sure it's all the way under the radiator and toward the left side of the car. When the coolant shoots out, it's going to splash off the bottom of the engine and go everywhere.

 

Unscrew the radiator drain tap. It's toward the left side of the car. I think I used a 13mm socket wrench.

 

 

 

 

The Haynes manual also said to "repeat the process by unscrewing the cylinder block plug located on the right-hand side of the engine". I couldn't find it. I may also have needed to have the car jacked up in order to get to it. I figured it wasn't important since I really only cared about draining and removing the radiator.

 

Step 2: Remove the radiator

 

Disconnect the top hose, then the bottom hose. The top hose was easy to get to. I had trouble with the bottom hose. Once I got it the hose clamp loose, the hose was stuck tight. I removed the hose clamp on the other end and removed that piece.

 

 

 

There are four self tapping sheet metal bolts (10mm heads) which hold the radiator to the front of the car (mine only had 3, and the missing fourth bolt turned out to be important). Remove those bolts and you should be able to remove the radiator.

 

 

 

Step 3: Clean and Paint (optional)

 

My philosophy when I do a job is that I leave it better than I found it. I noticed my radiator was kind of rusty. so I thought it would be a good idea to clean it up and add some paint to protect it from rusting further. First, I sprayed down the radiator with my garden hose in order to clean out the bugs. I used some gloss black Rustoleum spray paint and a small wire brush. I brushed away the rust from the mounting frame, but did not brush or paint the cooling fins as they are delicate and didn't want to damage them.

 

 

 

 

 

During my inspection, I noticed that the mounting plates (which I thought were removable) look as if they were intended to be attached to the radiator. The tops were coming apart, but the bottoms were still attached. Not sure what to make of this.

 

 

I also wanted to repair and paint the the rusty front engine compartment that had been hidden by the radiator since it would probably be a while until I got to that area again, but all I had was this spray paint, and I didn't want to risk painting stuff that I didn't mean to paint. So I decided to wait. Any tips on a good brush-on paint?

 

 

Step 4: Install the Fan

 

Since my fan was missing (the previous owner removed it because it was broken), I bought a good, used one from someone local. There are four bolts which attach the fan.

 

 

I'm not sure what it is called that the bolts are attached to, but in order to loosen the bolts (and keep the plate from spinning), I had to apply pressure to the belt while unscrewing the bolts.

 

 

There is a plate which attaches to the fan. Since there wasn't a fan already in there, I had to guess as to how it went back on. I didn't even realize until now that I might have put the plate on the wrong side. I assumed that it went on the back of the fan, and because the plate has a lip. Looking at it now, I think the lip on the plate is meant to face outward.

 

 

 

Step 5: Reinstall the Radiator

 

Put the radiator back in with the four mounting bolts and connect the hoses. You can even tighten the drain tap bolt before putting in the radiator. You will notice the amount of clearance from the fan to the radiator is in millimeters. When I first installed the radiator, I only used the 3 bolts that came out, and the radiator was separated from the engine mounting point by about an inch. So when I started my car back up, the fan would get caught on the radiator and couldn't spin (backing up the whole system in a horrible way). So I had to go buy another bolt in order to get a few more millimeters of clearance. I couldn't find a metric bolt on a late Sunday afternoon, so I settled for a #12 self tapping bolt.

 

3 bolts:

 

4 bolts:

 

Step 6: Fill with Coolant

 

Pre-dilluted coolant costs twice as much as full strength, so I decided to save a few bucks and mix my own. Find a bucket without a hole (apparently my bucket had a pinhole which made me leak coolant everywhere).  Fill half the bucket with coolant (or half the jug of coolant, whichever comes first), and half water. Fill the jug with water too, so now you have your own 50%-50% mix of coolant for refilling. Use a funnel and fill your radiator so it's about an inch from the top.

 

Step 7: Start the engine

 

Start your engine so you can see your fan spinning freely and that it's not getting stuck on anything. Allow the coolant to circulate. Be sure to CHECK FOR LEAKS. Recheck the coolant level.

 

At this point, I thought I was done. I called it a night, drove the car to work the next day and admired how my car stayed cool all the way to work without even getting warm. After work, I got about half way home (~ 4 miles) when I realized my temperature was in the red. Worse than before I even started this job!

 

The problem was that I didn't check for leaks. I thought the little bit of dribbling from the bottom of the radiator was just running on the outside was due to me spilling a little while filling the radiator. At some point during this process, a small hole at the bottom of the radiator core had been created. This caused a slow leak which drained all my coolant by the afternoon. So on my drive home from work, I didn't have any coolant left! I thought maybe I didn't tighten a hose enough and I had a leak that could be fixed, but when I got home, I refilled my radiator with water and could see that my radiator is in fact leaking. I didn't need to start my car. In 10 minutes, enough water had leaked out that I could see the top of the inside of the radiator.

 

Now I'm stuck with trying to figure out what to do (or what I've done wrong). Maybe you can help me? Is it possible/worth it to repair the radiator, if I can find the leak? Is it in too bad of shape to reuse? Should I find a good, used 2002 radiator? Is a good one cheap/easy to find? Should I upgrade to a newer model radiator and electric fan? Which model should I get, and where should I look to buy it?

Edited March 25, 2014 by andrewhavens

[pklym]

The "move the heater control switch on fascia" means to the right of the steering wheel. Move the climate control switch to "HEAT" which opens up the heater control valve allowing coolant to flow freely from the heater core along with the rest of the cooling system. It would allow you to get more coolant out, and may help avoid air bubbles when you refill.

 

I don't have much advice for you on the radiator. I would probably say since the mounting plates seem messed up on yours that I would not bother taking it to a radiator shop and would just replace (if you get a used one, I would take THAT to a shop to get tested and flushed).

[Guest_anonymous]

The metal plate fastens to the outside of the fan with the lip out to keep the plastic from deforming and to allow proper tightening of the fan by sandwiching it. Your clearance to the radiator will be compromised with the plate behind the fan also. There should be lock tabs behind the bolts. The heater valve is the cabin temperature control. the facia is the dash panel that says hot/cold. You open this to allow the "coolant" mix in the heater core to drain.o
Yes your radiator can be repaired. Bring it to a radiator shop. They will tell you the condition of the radiator and if it is worth working with the one you have. You can use a stock two core radiator or upgrade to a three core available through a performance vendor, or even fit a 320i radiator with some hose variation.
How long did you run in the "red" is the biggest question now. If/when you need to remove the head, you will need to locate the block drain
The paint condition behind the radiator is a tertiary issue in comparison to the more structural issues with the car. You can address the inner nose at a later time if/when you continue with this shell.
When you refill and run in the "coolant" mix it is suggested to "burp" the car to evacuate any air bubbles that might trap. Also fill the radiator above the core about an inch, but not to the filler neck. the top of the radiator is the expansion tank, if you overfill it will evacuate to the ground via the small tube at the to left side when at operating temp.

Edited March 25, 2014 by daron_in_cognito

[Stevenc22]

They make proper radiator paint which is better for heat transfer

 

http://www.amazon.com/Eastwood-Radiator-Black-Finish-Aerosol/dp/B003CRM9CU/ref=sr_1_2?ie=UTF8&qid=1395752396&sr=8-2&keywords=radiator+paint

[Conserv]

The radiator's "mounting plates" ("mounting flanges," or whatever they are technically) need to be re-soldered to the top radiator tank. If the flanges are only secured to the bottom tank, your radiator is "flopping in the breeze"! Yours likely either fatigued from use or separated from a minor front-end hit. A radiator shop will re-attach those areas. Re-coring will take your top and bottom tanks and install them on a brand new tube-and-fin section. But if your leak is indicative not of a bad tube-and-fin section, but of an irreparable bottom tank, a radiator shop will probably recommend outright replacement.

Good job, though!

Steve

Edited March 25, 2014 by Conserv

[Mike Self]

One more suggestion:  replace the factory-supplied bolt used as a radiator drain with a proper petcock.  I've never been able to find a petcock with 8x1mm (fine) threads, so had to do some improvising.  You can either re-thread the bung that the bolt threads into (it's soft brass so rethreading is easy), find a petcock that can be rethreaded to the proper size or find a petcock that will fit in the opening and solder in in place.  You may have to use an elbow so the drain cock will clear the fan and the body sheet metal below the radiator.

 

And while the coolling system is drained, you can do the same thing for the block drain.  But since that drain bolt threads into cast iron, it's much easier to re-thread a brass petcock to fit the existing threads in the block.  

 

Make sure both petcocks have nipples so you can attach a short length of hose to direct the coolant flow into a bucket or drain pan. 

 

cheers

mike

[ranger]

I have an almost brand new radiator that I would sell, if interested

[Andrew Havens]

Thanks everybody. Lots of great advice. Took my radiator to Mac's Radiator Repair. They found the leak and repaired it and reattached the mounting flanges on both sides for $48. They said it was still in pretty good condition, and I assumed recoring or buying a new radiator would cost much more, so $48 seemed reasonable.

Went back to fix my cooling fan the way it was meant to be attached by sandwiching the fan between the plates. I messed with it for an hour before I realized that there are two mounting plates. Make sure the holes line up because the threads are on the rear plate.

Even after lining up the plates, I found it easier to "seat" the fan by screwing in a few bolts first, then taking them out again.

Then make sure the plate goes on the face with the lip facing out.

After installing the fan properly (and mounting the radiator with all 4 bolts), there seemed to be an adequate amount of clearance.

Now my 2002 is back on the road with no leaks!

[peterschop]

Forty eight buck, you did good. When my car was overheating a couple of years ago, I took the radiator out, poured water in the top and it just trickled out the bottom. No leaks, just blockage. Had a new core put in for $350. 

[OriginalOwner]

$48 is a great price ...... and good to see you now have everything installed correctly.

 

And with an eye to the future:  keep an eye open for a 3-row core, they really help with cooling.  I bought one a few years ago, my local radiator shop installed it using the original tanks and frame for that OEM configuration, fit, and installation.

 

Cheers,

 

Carl

[PaulTWinterton]

Confirmation on value of 3-row core, please.

 

It's my understanding that the tii is under-cooled, especially for hard driving and summer heat while idling for long periods of time.  Like stuck in (stop and go) traffic.  My car runs with the temp gauge just below center until the above situations arise, then it steadily climbs to just-below red.  It has never gone into the red. 

 

For you folks who live in perpetual summer, do you share these symptoms?  Is the 3-core rad the answer? 

[OriginalOwner]

I recall reading "somewhere long long ago" that long long ago BMW designed a radiator to handle the cooling needs of the 1600 series.  However, the 2002 series did not get a newer/bigger/better radiator, but instead uses that same 1600 radiator, and is known for being cooling-challenged.

 

My personal tii experience:  yeh, my temp needle moves around a small amount, but never with that sort of mood swing in traffic.

 

I've had a 3-row core for years and years, and haven't had problems.  So it's one of those upgrades that I believe are a good idea since it does reduce the mental strain.

 

I found this interesting article, there are sections on the topic of cooling.  Not specific to the 2002, but some good cooling system theoreticals ..... 

 http://blog.bavauto.com/12247/bmw-and-mini-diy-overheating-cooling-system-diagnostics-how-to/

 

Cheers,

 

Carl

Edited March 30, 2014 by OriginalOwner

[oclee118]

 

 

Attached is the diagram of the fan and parts description. Hope it helps.

 

Good Luck!

[ndog]

u should find the block drain plug and pull it ,If you are filling/draining your system it might help to get all the crap completely out of the block.(wilst r/r radiator work)

[peterschop]

What ndog said. I was able to pull my block drain plug from under the car by reaching up under the exhaust manifold. When you take the plug out, you may have to poke a wire or screw driver into the hole to break through the crud build up.