If you haven't already bought the plastic screw. A brass bleed screw "upgrade" is available from some of the usual parts retailers. I have one in my E46 and my E53. Just don't go crazy tightening it.

Of course there are times where something is not there at the time of the inspection or is missed.

Peace of mind and best practices are untouchable positions but the fact is some folks have limited expendable income. I don't think overhauling a system because of the failure of one component should be presented as if that is the only alternative to prevent a catastrophic engine failure.

Building a scenario of why all hell is going to break loose if you don't do an overhaul, or what happens with an E39 or most mechanics say with blank miles etc. are misleading to me. When there is a cooling system leak there will be loss of coolant or coolant on the ground. When a cooling system component fails the temperature gauge will peg and there will be a warning light on the dash. They will likely be steam rolling out from under the hood. It doesn't matter how loud the engine or radio is--it will be like old faithful sets off. If one is a member here I am quite sure they will notice one of those things and pull over and shut off the engine. I've been running high performance engines for decades. Overheating is quite a common problem even with all new components. If my pea brain notices a problem before there is engine damage I see no reason most here wouldn't as well.

Why are there so many comments like---you can't have a BB gun, you're going to shoot your eye out?

I'm with bc on this. I'm also one that has a 1.4 bar cap. I don't see my entire cooling system or radiator fail because I never changed it.

I agree with much of what you said. There is no need to replace every component of the cooling system if you are a vigilant individual. Most of the driving public is not unfortunately. Used to see it all the time at the shop.

If there is steam rolling out from under the hood of a BMW... any BMW from 1983+ there is a very good possibility that the head gasket has already popped at best, or the head has warped at worst. It's good practice to, at minimum, do the WP, expansion tank, and thermostat every ~100,000 miles or so. All of that can be done for less than $150 using OE parts.

1+,

I am sorry but I have to disagree with "bcredliner".

So many people lose the head gasket in E39 forum (M52 and M54 engines). In the E39 forums, every week, there is a post about overheated engine, mainly because of neglect. By that time it is too late.

M52 is a bit better b/c the block is iron, so just do the head gasket, valve jobs, valve seals and done with. The block is usually OK.

M54 is a bit more complicated, once the engine overheats, it is not only the head but the head bolts usually strip out of the aluminum block. One will need to do Timesert or use Mercedes head bolts.

Let me be clear: I am not a parts swapper. I trouble-shoot things carefully before replacing parts.

The cooling system is an exception. A cooling system with > 100K-120K miles is like a time bomb...the consequence when the bomb explodes is very severe (overheated engine and head gasket job is not cheap)...

So, it makes sense to prevent the bomb from exploding.

I have fixed BMW for 30 years, and have never lost an engine from overheat (yet).


Having said that:

1- If one:
---> a. is vigilant watching the temp gauge all the time,
---> b. only drives around town
---> then one can leave the cooling system alone and fix it as it comes.

2- However if one:
---> a. is not vigilant
---> b. regularly leaves town...
---> then a cooling overhaul is recommended.

My cousin owns a BMW indy shop in L.A. area, he has seen so many overheated and trashed BMW engines, now he only sells cooling overhaul, otherwise no warranty of the work...

PS: The argument of no "extra income" does not fly. If people own a car, they need to budget money for registration, insurance, maintenance (either emergency or preventive stuff) to make the driving experience more pleasurable.

Temp gauge is also buffered so if masks the initial overheating and there is no audible warning.

You either modify the temp gauge buffer - DIY: Changing Temperature Gauge Buffer Range with PA Soft 1.4 - E46Fanatics

Add a Coolant Snitch if they are still available - CoolantSnitch(tm)

Or run a UltraGauge and see threshold alarms - UltraGauge OBDII Scan tool & Information Center

I agree if one is driving long distances away from home base preventative maintenance is far more important. Nothing worse than being stranded somewhere without the proper tools and the choices for repair shops are not familiar with a BMW. If I didn't mention that I should have.

I also agree that overheating can cause much bigger problems, and aluminum heads and/or block increase the risk of that happening.

I agree that owners of cars that are out of warranty should put money aside for repairs and maintenance. I don't believe that is the reality of a very large percentage of owners and I think they should know they do have an option even if it is less than the optimum and involves higher risk. I am saying the lifecycle of one cooling system component is not necessarily the same as another so the failure of one component doesn't mean there is no other option that can be considered. No need to be sorry to disagree. It's just my opinion and I respect yours.

As I mentioned, OP certainly made the best decision. My only purpose has been to let OP and readers know that IMO piece by piece replacement is not a certain engine death sentence and that it is not irresponsible if that, for whatever reason, is what one needs to do.

:iagree:
In a DIY world, part by part replacement based on failure, wear, leakage, etc is a normal accepted practice. Observation, awareness, test and repair as needed.
With this practice there is little or no risk to the entire drivetrain due to a part failure. After all labor is free with this task model. Parts are the only real out of pocket costs.
In a DIFM world, replace everything as the average owners will say, "you touched it last therefor your fault." "You should have known...."
80-100k replace everything.

Yes, I noticed that. I've got both the brass and plastic ones (2 of those, actually) in my cart now.
BMW X5 3.0i Sport Utility E53 3.0L L6 Bleeder Screw with O-Ring for Cooling System
BMW X5 3.0i Sport Utility E53 3.0L L6 Bleeder Screw with O-Ring for Cooling System

I was all set to buy the brass one, but then I got to thinking a little ... is it actually better to have a plastic one in there (and a spare) so it will break if I or someone else over-tightens it?

I'm assuming that's what happened here. I must have overtightened it for no reason at all, probably while checking everything in sight while buttoning up after my recent voltage regulator replacement.

Easier to replace the plastic screw than just about anything else that may break first. Of course, step one is to not over tighten it.

Regarding overhaul or not, everyone's got good points, and I agree that basically it depends on the owner's situation. For the exact same car, I'd do it differently for myself than I would for a family member who lives far away.

Some other factors in that area, that are actually present in my situation are:
1. The driver and proximity are unknown. Me, one of my kids? Locally or away at college? Just this last little episode shows how being separated from the car makes simple things a lot harder.

2. Service records are incomplete. In my case, I know some things have been replaced, but if something is not in the records, what do I assume?

3. Availability of time to work on the car - not much right now, may have more in a month, etc.

The car has 173k+ miles now (2001 3.0i AT). Records (again, expected to be incomplete since there are gaps, and through digging, I have found a few more things that were not in the records given to me at purchse) show, all local dealer work:
61k - reman water pump put in because original was leaking
158k - thermostat housing, thermostat, gasket
- expansion tank
- complete CVV system
- DISA valve
- MAF sensor

(more complete info, with part numbers is below)

So I don't know about the radiator, water pump (112k miles on the reman now). I've seen the radiator many times, never thinking of it as anything other than original, but never inspecting it carefully to be sure. The radiator hoses all look ~new, probably replaced during the 158k repair bomb, I'll guess. BTW, the PO ended up selling me the car for a fraction of these repair costs ... and then bought a new X5!

I generally like to do all the PM required and then some, what I call "pre-emptive repairs" rather than PM. So I did cn90's pulley overhaul, and OFHG gasket tutorials. While doing those, I confirmed that the water pump feels good. Not _perfectly_ tight, but smooth.

I think I've got my family trained to pay close attention to gauges and know never to drive when it is showing HOT.

So I'm inclined to pay a little extra attention to the radiator and water pump, but not do anything for now.


More complete related service data:
6-Jun-05 61343 Stevens Creek BMW
$561 Replace water pump with remanufactured one 11-51-7-527-910
$22 replace coolant 82-14-1-467-704

15-Mar-13 158191 Stevens Creek BMW
$576 Replace air intake boot 13-54-1-440-102 tube elbow
$693 Replace thermostat housing with thermostat and gasket 11-53-7-509-227
$24 replace coolant 82-14-1-467-704
$614 Replace valve cover gasket. Set includes VCG, spark plug gaskets, VC bolt seals. 11-12-9-070-990
$41 replace 15 x valve cover bolt seals 11-12-1-437-395
$1,015 Replace transfer case
$2,413 transfer case. AT-auxiliary transmission 27-10-7-504-568
$136 rubber mounting. Transmission mount. 22-31-6-754-088
$1,119 replace CVV valve and all hoses
$90 replace CVV valve 11-61-7-501-566
$40 replace vent pipe for oil separator - from valve cover to oil separator 11-61-1-432-559
$51 replace Connection Hose for Oil Separator - From Valve to Air Distribution Piece 11-61-7-504-535
$53 replace Return Pipe for Oil Separator 11-61-7-504-536
$27 replace vacuum hose, black 11-72-7-545-323
$43 replace vent hose - Dipstick tube to oil separator 11-15-7-532-628
$340 Replace Intake Manifold Actuator - DISA valve 11-61-7-544-805
$100 Replace expansion tank 17-11-7-573-781
$555 Replace mass airflow sensor 13-62-7-567-451