coolant leak

[m5james]

Upper radiator neck failures, heater diverter valves, fan clutches, valley pan gaskets and expansion tanks have always common in BMW V8 since the mid 90's all the way up to today, even in the N62 powered 745's....X5's will experience it soon enough. If you've got over 80, 000 miles, I'd simply replace...everything! Radiator, waterpump, thermostat, upper and lower hoses, OSV valve while you're doing the valley pan gasket and the expansion tank. Spending $1000 now in one big shop is easier than spending hundreds here and there when little things keep breaking because you only replaced the items broken at the time...not to mention the headache and danger of a catastrophic failure on a roadtrip or something. When people only replace one thing at a time in regards to the cooling system, the better performance of the new stuff will make the old stuff fail all that much sooner. Sometimes the movement of replacing little items also increase the stresses of the old items, then you'll be back in the shop again a week later. I know it might sound like I'm trying to use scare tactics, but I've been reading about these same cooling system problems since I purchased my 98 740iL, and seeing that we share the same motor, we inherit the same problems.

[we350z]

are you saying i should replace other shit now? i have 74K almost on the odo. if rad goes thats easy enough. i didnt replace the hard to get to non-typical coolant hoses. so what will my new parts be stressing exactly? i am worried about that valley pan gasket as well. i fear that oil seperator is next. please advise. hard for me to justify laying down the cash on preventative maintenance.

[m5james]

LOL...up to you bro. I thought you replaced just about everything anyways. What didn't you replace? Maybe I can give you my .02 about what you might wanna consider doing before summer hits.

[we350z]

coolant reservoir was replaced 4 years ago and looks fine, besides that i replaced:

- water pump
- water pump small hose
- thermostat
- both belts
- upper rad hose
- lower rad hose
- both reservoir hoses

what i did not replace

- radiator
- small hose that runs length of radiator
- any other coolant hoses

[m5james]

I'd be cautious of the radiator neck and the fan clutch blades. Not try to go for scare tactics here, but the necks are prone to cracks. I've seen a handful fan blades that got so dry and brittle that they broke under centrifugal force...taking out everything in their path and literally going through the hood in a few instances. I've deleted my fan clutch for an electric fan conversion years ago.

[London5]

Greetings from London,

I'm having my annual X5 issues so could do with your help.

It’s a 2001 Euro V8 44,000 Miles

Coolant Leak
Rear Wiper gave up the ghost, sounded like the motor was being strangled, then stopped.

I've had a good read of all the information on here re losing coolant and have realised the Coolant Reservoir PN 17107514964 needs replacing.

You can see small veins of coolant coming out the join in the reservoir after time it fails big time.

Its MOT test is due so I informed the garage of the easy job and they said they'll swap it.

He called me today telling me he'd be ordering the part (why did you not pre-order). In his opinion the system heated up too quickly suggesting may be a head gasket, too much pressure.

He'd have to replace the reservoir to tell, my shit Sherlock.

I challenged his sweeping statement based on:

1) My knowledge of how long it takes to heat up from cold

2) The numerous other more frequent reasons documented on this great site (water pump, oil separator etc....etc..)

3) No discharge on the oil cap

4) No change in exhaust output

I said I'd pop down tomorrow morning to see it for myself.

Can the coolant pressure be tested?

How do you tell the head gaskets gone or going?

Thanks

B

[amacman]

the coolant can be tested for hydrocarbons , if present that would possibly indicate head gasket failure .
the probe used for exhaust gas analysis can test the coolant or a sample of coolant can be mixed with a chemical ( forgot what it`s called , which will change colour if hydrocarbons present .

[London5]

Thanks for the info,

I flushed the system fully yesterday and replaced the tank.

All seems to be fine,no leaks, no increase in temp, no change in performance or idle

I'm getting the system pressure tested so I'd like to think that will be conculsive.

I may by a test kit to have a go anyway.

Thanks,

B

[Rockmelon]

i have my fair share. got the 'check coolant level' msg the other day. open up the reservoir & it appeared empty. fortunately the leak was easily to find. see pic below. filled up about 1 litre of 50/50 mix for time being. good thing that the leak is not elsewhere. also found that the hose connecting to the ATF reservior is leaking. my goodness.

[London5]

Well it passed it's MOT (UK test) and they did a hydrocarbon test and it came back negative (no exhaust gases in the coolant).

I drove it 80miles watching the temp like a paranoid freak.

The guys still think the pressure builds up in the coolant system too quickly but were unable to test it saying I should take it to BMW.

What’s too quickly, any ideas?

My initial thought is they have no experience with V8's and should stick to tests however until I know for sure it's not worth taking the risk. Off to the dealership to pay $198 P/HR.

Nice !