Fan shroud removal help needed on 99 528it.

[Highgear]

I have coolant leaking on the left side of car. This is an on going problem. First the bleeder screw head had snapped on the upper hose on my wifes 99 528it. I just replaced the whole hose instead if messing with the rest of the screw. After this I noticed a small coolant on the ground after the car heated up (I did follow the correct bleeding process) I then found that I may have not have tightened the overflow tank bleeder screw enough because dry coolant spray was around it. I then tightened it a bit more. No more spray around that screw. I still found small spots of coolant on my driveway. So I now removed the bottom shroud from under the car to see if I could pinpoint the leak. No deal. It is leaking from the upper left side and dribbiling down the plastic side of the radiator. At this point I let it go for little over a month and just kept adding coolant. NOW, what ever is letting go is going. I had a trail of coolant leading into my driveway last night. Since the leak is high and I can't find it, I am thinking it is coming from under the fan shroud. Maybe the small vent hose that goes from the expansion tank to the radiator?? How do I loosen but not remove the fan shroud so that I can get a look underneath? Is it just removing the overflow tank bleeder screw and popping the plastic rivets on each side of the shroud?

[82bmw633]

There should be plastic rivets on top on either side. Beisan Systems has a complete guide to removing the fan shroud (with photos) on their web site.
Here (http://www.beisansystems.com/procedures/e39_fan_procedure.htm) is the guide.

[e39dream]

have the cooling system pressure tested to reveal the true cause of the leak, this is not something you want to trial and error. If you dont catch it this can cost you an engine.

[Highgear]

have the cooling system pressure tested to reveal the true cause of the leak, this is not something you want to trial and error. If you dont catch it this can cost you an engine.
I agree, The funny thing is that it is more like a leak that is not under pressure. I see no steem, so that is why I think it may be that overflow tank hose. If I see that is not the problem then I'll take it to my mechanic friend for a pressure test. BTW, thanks to the other poster for the link on the shroud removal.

[e39dream]

that makes no sense whatsoever. If it leaks with the engine off, it's going to leak more while it's running. Coolant expands and creates pressure as it is warmed. Your car has a cap on the expansion tank that is designed to release pressure should it reach 2 bar or roughly 29 PSI. So assuming all the hoses and other parts are good that system could see almost 30 PSI before the cap lets loose, which means your cooling system needs to be capable of holding that pressure leak free so the cap is the weakest link.

any leak that lets coolant out is creating an air space in the system. Once that air space grows enough it locates itself near the thermostat and upper hose and that is when the problems will really become apparent to you.

Bottom line- your eyes are not sufficient diagnostic tools for this sort of work. I've been there, trust me. Nothing is worse than thinking you have fixed your slow coolant leak only to have the car overheat a week later. You can get a cheapy pressure tester for less that 100 dollars. It's a very basic test that will save you a lot of frustration.

[Highgear]

that makes no sense whatsoever. If it leaks with the engine off, it's going to leak more while it's running. Coolant expands and creates pressure as it is warmed. Your car has a cap on the expansion tank that is designed to release pressure should it reach 2 bar or roughly 29 PSI. So assuming all the hoses and other parts are good that system could see almost 30 PSI before the cap lets loose, which means your cooling system needs to be capable of holding that pressure leak free so the cap is the weakest link.

any leak that lets coolant out is creating an air space in the system. Once that air space grows enough it locates itself near the thermostat and upper hose and that is when the problems will really become apparent to you.

Bottom line- your eyes are not sufficient diagnostic tools for this sort of work. I've been there, trust me. Nothing is worse than thinking you have fixed your slow coolant leak only to have the car overheat a week later. You can get a cheapy pressure tester for less that 100 dollars. It's a very basic test that will save you a lot of frustration.


Well, I lifted the shroud up to take a peek and everything is dry under there. What I met leaking not under pressure is the it does not have to be hot. I now think that it is the radiator. I refilled the radiator, put the heat on to 90 deg. ,cracked the bleeder and it is pissing coolant in a steady flow just below the upper hose. It is not comming from the hose connection. It must have a crack where the aluminum meets the plastic part of the radiator.

[e39dream]

I see what you mean now, sorry. It is not uncommon for these to blow the neck right out of the radiator's upper hose connection. Sometimes the plastic itself fails and breaks, other times it leaks where the plastic tanks meet the aluminum core. You can get a good price on an OEM radiator from www.eactuning.com

[occhis]

Complete cooling overhaul recommended if not yet done. All those plastic parts are not to be trusted.

[Highgear]

Complete cooling overhaul recommended if not yet done. All those plastic parts are not to be trusted.

I hear that a lot on this forum. I plan on changing the hoses on the overflow tank and the bottom radiator hose. The upper is new. Lots to choose from. Is Nissans (sp.?) a good brand?