540i Cooling System - Full Overhaul

[GTO78DB]

Well I went out to my garage last night and saw that a long puddle of coolant had made its way over to my downhill wall... Looks like the damn cooling system is finally done with!

I have 69,600 miles 1997 540iA, and since i've owned the car at 48k about 1 year 3 months, it has had a smaller coolant leak, but the last few weeks the puddles under the car have been bigger, but I still didnt bother to attempt the DIY.

I bought the cooling system parts several months ago, but just didnt do the DIY procedure for various reasons..

Now I am starting to tackle the job.. I do not have a 32mm wrench, nor the special Fan Clutch tool!! What is the best method? I am not happy about this issue.. please help!

For people that have done this, were the main hoses from the radiator to the waterpump really hard to get off? Its like they are baked on to the radiator over 11 years, and i am worried if i force them i will break other parts in the area.. How did others get the big hoses off once you took off the metal circle clamp?

for the 1997 model, can I tuen the car to "ON" position, put the car to 90 degrees and low fan, to drain the coolant? Then also the same procedure to refill the coolant? Help! I saw somthing in the Bently that said "late model cars" cannot do this???? IS THIS TRUE??

I am getting a little pissed.. is this something that can be DIY?

ANYONE IN TAMPA / WEST FLORIDA???? I would love to talk to someone thats done this procedure, please PM me, HELP!!

Thanks in advance..

[BlackBMWs]

O.K. You're about to get a whole lotta help on this topic from a bunch of folks. I myself just did this job two months ago.

http://forums.bimmerforums.com/forum/showthread.php?t=1139685 Never mind the Zionsville stuff...

CN90 mentioned somewhere you can find the 32 mm wrench at a bike store. Autozone or a auto shop may have it and the fan clutch tool for loan or rent. I did not need it as a swift tap on the 32 mm wrench with a mallet was enough to free the nut for me without the holding tool. I sprayed the nut and shart with penetrating oil before starting.

If you have matching hoses, just cut the hoses fo get them off whereever they are baked on.

It is an easy job, it does require a few special bits and simple tools and requires a little patience.

[KellyC]

You can get the special tools online and it will make a big difference in the ease of the work. The 32mm wrench can be found at bicycle stores for much cheaper than online.

If you are replacing the radiator and hoses how you take them off at the radiator is not important, you will probably break the plastic collar at radiator trying to twist them off. At the engine/water pump side just twist the hose off the metal housing, or if replacing the hoses, cut the hoses lengthwise along the barb. Make sure you replace the reservoir and the plastic bleed screwl as the plastic in those things are cheap and don't react too well to heat.

To drain the coolant, drain the radiator first with the car COLD. There should also be two drain plugs on either side of the engine block to remove the remaining coolant. You can flush the coolant out using a garden hose if you want to remove all the residue. To fill the coolant, just button everything up and fill via the reservoir/expansion tank until it overflows. Run the car, open the bleed screw at the reservoir and bleed out the air, add any make-up coolant as necessary and check for leaks.

[BlackBMWs]

on the refill, you can also fill what you can with a 50/50 mix of the right coolant. (I use BMW OEM and distilled water, other folks use other appropriate fluids) then turn on the aux water pump without turning on the engine by turning the heater temp up on high, fan low. This will circulate the coolant and help fill faster. on the stock cooling system, open the bleed screw for next to the coolant recovery tank.

When you pull the waterpump, be careful not to pull the two metal cooling pipes that go to the rear distribution manifold. on the 97, I don't know if your hoses have the quick release clips on the hose ends. If so, those are actually easy to remove.

When you get to the water pump removal, you will find the harmonic balancer in your way. You can get to the last bolt by just using a 10mm thin open end wrench. Also, there is an air emissions metal tube in front off the water pump. two 10 mm bolts a one torx bolt to get that off.

Leave the belt on until you remove the four bolts for the water pump pulley. Makes it easier to loosen them while the belt is providing tension.

CN90 has a DIY somewhere... Let me look for you since it looks like you are doing this now.

[GTO78DB]

I have a radiator, 2 big upper hoses, water pump, tstat, belts... So I do have the parts to redo the cooling system. But I do not have another car, and cannot find a ride as of now to go up to get the 32mm and possible special fan clutch tool!!! ARG!

Do I remove the silver throttle bend piece that is after the MAF and Air intake tube? That seems to be in the way for doing some of these things..

So to refill the coolant, I do not need to turn the car to "ON" then put temp to HIGH = 90degrees and blower to low? Thats what the Bentley Manual said..

I have put it back together and have added coolant, to see if when i start it and have it running that it will leak out badly... I had just driven 200 miles or so total yesterday, before I parked it in the garage, and came out later at like 10pm, to see the long coolant line flowing downstream towards my garage wall!

What would you guys do? Try to run the car, make it to like autozone, watch the temp guage like a hawk, get the special fan clutch tools? or just try to get creative and get the fan clutch off?

Can someone PM me? I would love to talk to someone on the phone...

[BlackBMWs]

Good talking to you today. Put together a plan to be car-less if you need to, to give yourself enough time and focus to get the job done right. Sounds like you have the skill and know-how to get this done.

Pizza and beer to the buddy who helps you get the wrench,distilled water and perhaps other unforseen trips.

Take your time and give me another call if you get stuck... :cool

[jamesdc4]

Well I went out to my garage last night and saw that a long puddle of coolant had made its way over to my downhill wall... Looks like the damn cooling system is finally done with!

I have 69,600 miles 1997 540iA, and since i've owned the car at 48k about 1 year 3 months, it has had a smaller coolant leak, but the last few weeks the puddles under the car have been bigger, but I still didnt bother to attempt the DIY.

I bought the cooling system parts several months ago, but just didnt do the DIY procedure for various reasons..

Now I am starting to tackle the job.. I do not have a 32mm wrench, nor the special Fan Clutch tool!! What is the best method? I am not happy about this issue.. please help!

For people that have done this, were the main hoses from the radiator to the waterpump really hard to get off? Its like they are baked on to the radiator over 11 years, and i am worried if i force them i will break other parts in the area.. How did others get the big hoses off once you took off the metal circle clamp?

for the 1997 model, can I tuen the car to "ON" position, put the car to 90 degrees and low fan, to drain the coolant? Then also the same procedure to refill the coolant? Help! I saw somthing in the Bently that said "late model cars" cannot do this???? IS THIS TRUE??

I am getting a little pissed.. is this something that can be DIY?

ANYONE IN TAMPA / WEST FLORIDA???? I would love to talk to someone thats done this procedure, please PM me, HELP!!

Thanks in advance..
GTO78DB,

If you have already read these threads, then please disregard my post.
If you haven't read them, it's required reading before tackling the DIY. :D Some of the questions you ask lead me to believe you haven't read them yet, so here they are. :)

540i M62 Thermostat Replacement (http://forums.bimmerforums.com/forum/showthread.php?t=882159)

Belt Replacement Instructions (Incl. Fan Removal) (http://www.bimmerboard.com/forums/posts/119957)


I have a radiator, 2 big upper hoses, water pump, tstat, belts... So I do have the parts to redo the cooling system. But I do not have another car, and cannot find a ride as of now to go up to get the 32mm and possible special fan clutch tool!!! ARG!

Do I remove the silver throttle bend piece that is after the MAF and Air intake tube? That seems to be in the way for doing some of these things..

So to refill the coolant, I do not need to turn the car to "ON" then put temp to HIGH = 90degrees and blower to low? Thats what the Bentley Manual said..

I have put it back together and have added coolant, to see if when i start it and have it running that it will leak out badly... I had just driven 200 miles or so total yesterday, before I parked it in the garage, and came out later at like 10pm, to see the long coolant line flowing downstream towards my garage wall!

What would you guys do? Try to run the car, make it to like autozone, watch the temp guage like a hawk, get the special fan clutch tools? or just try to get creative and get the fan clutch off?

Can someone PM me? I would love to talk to someone on the phone...
I don't know how much information was exchanged in your conversation, but if other members are reading this and wondering, it would be nice to have the answers posted in this thread for the collective.
I'll attempt to answer some of them (correctly, I hope).

- There are four more hoses between the firewall and rear of the engine that you should replace while you are doing this overhaul. If you don't replace them now, they may end up being an uneccessary PITA sometime in the near future. You do not mention the expansion tank or the bleeder screw that are mentioned in one of the earlier posts. These are very important and should be replaced as well.
Let's not leave out the fan and fan clutch. Exploding fans suck!

- I do not believe that you need to remove the silver throttle body to do this DIY.

- Turning the heat all the way up worked on my 98 540i, but I don't know about your 97. Seems like it should work.

- DO NOT drive the car anywhere until the cooling system is replaced. Take a taxi.

E39ers, Please correct me if I am wrong on any of these points.

Good luck

[BlackBMWs]

James,

He's probably working the replacement just now. We talked about NOT driving the car to go get parts and tools. He was getting a buddy to help out and possibly give him a ride to work tomorrow.

He's looking to replace rad, thermostat, two radiator hoses, belts and coolant as those are the parts he has just now. We discussed the same main points that are gone over with each renewal. I encouraged him to take his time so as not to have rework later. I too look forward to hearing how the install went. :cool

GTO78D8, if you do have extra time and cash, do consider swapping out the coolant recovery tank, Rad hose temp sensor/o-ring and other hoses. Jared here on the forum can probably get you the parts next day if you can't locate them locally.

[GTO78DB]

Got everything taken care of this weekend. New water pump, thermostat, expansion tank, radiator, upper hoses.

Thanks for the help guys, thanks again Rich for the detailed explaination of the process.

A few comments about the install:

1 locator pin for the water pump would not come out of the old water pump. I seated the new gasket and took my time cleaning the surface on the block, so I feel that I got a great seal for the new water pump. Was it a major problem that I didnt have the 2nd locator pin for the water pump?

1 of the thermostat bolts was hard to get to, I found the best method was to use like a 6 inch extension on, and that gave me the proper space to get it off.

Radiator was a PITA to get out, had to gently slide it on the passenger side around the AC lines, then do a lot of creative manuvering to get the drivers side out, it is not a simple task. FYI.

PB blaster was amazing! Helped with the baked on hoses, and with the fan clutch nut. I had the 32mm wrench, and hit it with rubber mallet a few times, that didnt work, then I tried the screwdriver trick, and that worked, got the nut free.

Very happy to have this procedure done now. So far so good, not a drop of coolant to be seen.

Now onto throttle body gasket, and thrust arm bushings.

[BlackBMWs]

Got everything taken care of this weekend. New water pump, thermostat, expansion tank, radiator, upper hoses.

Thanks for the help guys, thanks again Rich for the detailed explaination of the process.

A few comments about the install:

1 locator pin for the water pump would not come out of the old water pump. I seated the new gasket and took my time cleaning the surface on the block, so I feel that I got a great seal for the new water pump. Was it a major problem that I didnt have the 2nd locator pin for the water pump?

1 of the thermostat bolts was hard to get to, I found the best method was to use like a 6 inch extension on, and that gave me the proper space to get it off.

Radiator was a PITA to get out, had to gently slide it on the passenger side around the AC lines, then do a lot of creative manuvering to get the drivers side out, it is not a simple task. FYI.

PB blaster was amazing! Helped with the baked on hoses, and with the fan clutch nut. I had the 32mm wrench, and hit it with rubber mallet a few times, that didnt work, then I tried the screwdriver trick, and that worked, got the nut free.

Very happy to have this procedure done now. So far so good, not a drop of coolant to be seen.

Now onto throttle body gasket, and thrust arm bushings.

Anytime... Glad it all came together for you. It will be easier for you to sleep now, I imagine... :cool