Newbie with Cooling Issues...

S

stretch.

Member
Morning Everyone,

3.0 2004 Roadster (non si)

Coolant Light came on intermittently over a couple of days, level was fine, no problems with heating.

But...

Long motorway drive and the heater stopped maintaining a warm temperature, started blowing cold every time I slowed down below 50.

Car was fine for short use during the day, about 25 miles, no temp issues, heater fine.

After a drive through the illuminations at Blackpool (top down, naturally), the car temp kept hovering around red, then into the red, then back to mid point, then into the red ad infinitum, heater blowing cold.

Checked coolant next morning and the dipstick is well down, so I've topped it up, driven back home pretty gingerly, but temp sensor didn't move past normal.

So, what should I be looking for? I've read that there's issues with cracking on the joints of the expansion tank, the sensor causing leaks, heater matrix (but no damp carpet at the moment), water pump, thermostat...

Anybody point me in the right direction? Or suggest any decent online guides? I'm not too familiar with BMW's, I'm not too bad with a spanner though, after owning a VW Corrado for a few years.

Also, What service is at 92k? Looking to DIY everything if possible, only had the car for a month or so!
 
hhmm ? the intermittent cold air/warm air through heater can in worse case scenario indicate cylinder head problem :o have read here http://www.ehow.co.uk/about_5410839_bmw-head-gasket-problems.html
getting the coolant level just right can be tricky with too much showing a warning dashlight as well as too little . even when the float appears to have disappeared there can be enough in . depends on engine temp when you check it of course.
also make sure you turn the cap the extra turn after topping as under great pressure & can let surplus overflow .
the heater problem /temp gauge is more of a concern & as you indicate start with the smaller items like temp sensor .
oh & welcome to the world of zed & hopefully the knowledge you need will be here :thumbsup:
 
Ahh, crud.

I'm going to recheck the coolant at lunch (when the car is hopefully nicely cold) and see what it says.

Might have to check the cap for mayo.

To be honest, I think that the first time I checked the coolant level I didn't tighten the cap fully, so hoping that the loss of coolant was down to that.
 
I had a similar prob last week.

I'd only just bought the car and took the cap off to check the coolant. (didnt screw it on properly it would seem)

When I got to work the next day I had a puddle under the car.

Filled up with coolant screwed on tightly no more leaks...

but

my coolant float seems to be broken, any idea where I could source a replacement ?
 
I had exactly the same problems, turned out mine was 2 separate issues - The cooling fan was shot, and a heater stepper motor had gone haywire. Replaced both, good as new!
 
How is it that you bleed the system on these?

Read something about the N52 (2.5?) where you have to rev it from ignition and it starts an auto bleed set up or something?

Also, anyone know what the 90 ish k service is? Is it just filters and oil?
 
My vote would be for water pump failure. I believe the water pump has a composite impeller (rather than metal), which can slip on the metal shaft.
This is certainly the case with the M54 engine, not sure about the N52.

I has a slightly cold heater once and swapped the water pump myself as a precaution. I've also had coolant boiling (despite temp guage reading OK) in my girlfriends Fiesta which turned out to be partial water pump failure.
 
Sorry to add this into the mix, but it sounds exactly the right symptoms of a jammed thermostat - cold air through the blower due to the coolant not going round the warm engine, and overheating.

Shouldn't be too major
 
stretch. said:
How is it that you bleed the system on these?

Read something about the N52 (2.5?) where you have to rev it from ignition and it starts an auto bleed set up or something?

Also, anyone know what the 90 ish k service is? Is it just filters and oil?
Click to expand...
There are few absolute mileage scheduled procedures, mostly just do what the service indicator tells you to do. The few scheduled procedures are replace spark plugs and ATF every 100k miles and O2 sensors every 120k miles.

The N52 cooling system has unique bleed procedures due to the electric water pump. Do NOT rev the engine! Otherwise, your recollection is very close. The procedure described below covers most situations. A special procedure requiring the DIS computer is required for engine or heater core replacement.

1. Engine must not be hot. Remove coolant cap and open bleed screw located just to the top (rear) right of cap. Slowly add coolant up to lower edge of filler neck. Close bleed screw once bubble free coolant comes out of bleed port. Replace cap. Do not open cap or screw during bleed procedure.
2. Connect a battery charger to avoid depleting battery.
3. Turn on ignition ( 2nd stop). Do not start engine. Set heater to max temp and activate “Auto” climate control button. Reduce fan to lowest setting.
4. Press and hold accelerator to floor for 10 seconds. Engine must not be running.
5. Bleeding procedure begins and runs for about 12 minutes.
6. If bleeding needs to be done repetitively, DME must be reset between procedures by removing key from ignition for at least 3 minutes. Re-enter procedure at step 3 above.

I'll vote for thermostat, though other possibilities are valid thoughts as well. It's not major, but it's expensive for what it is because the part includes the housing and associated wiring. It's a 103 C thermostat, so if you want to test it, it'll need to be heated in coolant.
 
mintstuff said:
My vote would be for water pump failure. I believe the water pump has a composite impeller (rather than metal), which can slip on the metal shaft.
This is certainly the case with the M54 engine, not sure about the N52.

I has a slightly cold heater once and swapped the water pump myself as a precaution. I've also had coolant boiling (despite temp guage reading OK) in my girlfriends Fiesta which turned out to be partial water pump failure.
Click to expand...

The OP has the M54 engine and from what I've read the water pump can be an issue if it has a plastic impeller.
 
Thanks for all the info! Glad I joined here!

Just need a dryish day soon to get under the car and figure out where this leak is from. Although, I think I might replace the thermostat as a precaution and swap in an uprated water pump as they seem reasonably priced,

The gf might not think so, but hey, you can live in a car, but you can't drive a house.
 
Aaaand I'm back,

I've finally had the chance to get the car up on some ramps, can't see anywhere obvious that's leaking, all seems dry underneath. I've tried running it up to temp too, no leaks.

The crazy part of my brain has started thinking possibly headgasket, I do seem to be getting a bit more smoke out of the exhaust than I would reckon is normal, but the mpg and performance are still fine.

Oil cap:


I think I'm gonna try and get it into my garage to get it pressure tested, should bring something to light at least, but any other insights would be appreciated.
 
Not all head gasket problems result in water in the oil. As you've indicated it can also exit via exhaust as steam. Having said that I don't think many M54 engines have head gasket replacements in their lifetime.
 
stretch. said:
Aaaand I'm back,

I've finally had the chance to get the car up on some ramps, can't see anywhere obvious that's leaking, all seems dry underneath. I've tried running it up to temp too, no leaks.

The crazy part of my brain has started thinking possibly headgasket, I do seem to be getting a bit more smoke out of the exhaust than I would reckon is normal, but the mpg and performance are still fine.

Oil cap:


I think I'm gonna try and get it into my garage to get it pressure tested, should bring something to light at least, but any other insights would be appreciated.
Click to expand...

so have you steadied the coolant going in ? ie / temp gauge not showing overheating & no dashlight ?
have you got warm air at anytime through the heater ? or is it coming & going ?
& oil filler cap ? is that just oil stained or rust ?
 
Temp gauge stays steady, get warm air through the vents although it does occasionally blow cold, intermittent coolant light, and it was just oil stained (I think...).
 
Headgasket on the M54 is unusual......I seriously doubt it ,....I found topping up the coolant is best done first thing in the morning , cold , and the level drops slightly a few times untill all the air is purged over a few journeys.
 
stretch. said:
Temp gauge stays steady, get warm air through the vents although it does occasionally blow cold, intermittent coolant light, and it was just oil stained (I think...).
Click to expand...

so are you still topping water & at what volume ?
the heater cold then hot is a classic head gasket symptom ,
running any BMW or any car hot is not good , depending on who owned it previously & how long its had the problem would obviously make the problem worse
continued running at hot temp in very very worse case can warp the head thus making the gasket leak
 
You must log in or register to reply here.

Similar threads

L
Newbie owner
Replies
4
Views
430
DMike
DMike
H
E85 3.0si Newbie
Replies
7
Views
2K
HazArc
H
M
Newbie says hello and asks the odd question
Replies
5
Views
519
Mr Tidy
Mr Tidy
L
G29 Newbie
Replies
10
Views
2K
sars
sars
M
newbie
Replies
4
Views
1K
Mr Tidy
Mr Tidy
Back
Top Bottom