Hello, Maybe someone recognizes the following symptoms and can give a possible cause, I have 325i. It over heats when stationary, and when driven hard, both can be controlled by turning the in car heater on. To rectify this problem to date I have changed drive belts thought they were squealing, but overheating and squealing persisted, so changed thermostat, made no difference, then flushed Rad, no joy, then to fix squealing and what I thought must be a water pump failing, I have replaced the water pump but still got same symptoms, my next move is to replace the Radiator and or Viscous fan, although can't see how fan could produce these overheating events.
Thanks for your help in advance
Overheating
Moderator: martauto
does your car overheat when the car is driven at a steady speed?
your viscous fan kicks-in when it gets hot. this sucks air over the rad when the car is stationary. this is a very common failure, most common symptom being car overheating when still but fine on the move.
there's a famous newspaper test you can do to test. when the car is warm, your fan should be able to shred a rolled up newspaper. If the newspaper stops the fan, the viscous is shot.
it's about £30-£50 new from a retailer, dunno about the dealer.
HTH
your viscous fan kicks-in when it gets hot. this sucks air over the rad when the car is stationary. this is a very common failure, most common symptom being car overheating when still but fine on the move.
there's a famous newspaper test you can do to test. when the car is warm, your fan should be able to shred a rolled up newspaper. If the newspaper stops the fan, the viscous is shot.
it's about £30-£50 new from a retailer, dunno about the dealer.
HTH
Temperature is fine at steady speed, the haynes manual does say the viscous fan should have greater resistance when you try to spin it by hand when hot than when cold, I tried that and thought it felt pretty much the same, maybe it is broken, anyway the car has over 170k on the clock now, so a new Rad would probably be a good idea, especially when I want to keep it cool on track days, the viens are also flattened quite a bit where the fan came into contact with the Rad when my engine mounts collapsed, I was lucky went to check water level when spotted engine had moved !! 
Pointing at your viscous as the culprit. If your rad was blocked, it wouldn't release heat from your engine whilst driving, but at that mileage a new rad is a good idea aswell. You might as well change all your hoses - if you haven't put some fancy silicone ones already for the track 
with the new pump, radiator, viscous and hoses your system should be good for another 80k
with the new pump, radiator, viscous and hoses your system should be good for another 80k
Thanks Adil786, I am not familiar with "fancy silicone" hoses!! how do these help? I have seen nice blue hoses on race cars b4, considered large core Radiator for track days, it was at a track day that the overheating problem started, having to top up after each session, with car pouring water out the overflow, not been right since, temp gauge at half way point, in car heating on full blast, couldn't keep my foot from pushing flat to the floor !!
i thought they were just coloured to look cool? 
nah, i "think" they're stronger and not prone to perishing like the standard rubbers so are uber reliable. you don't want a split hose when caning your car for hours on end. i've nver used them myself, i think e30 kits of 4or5 hoses costs about £150 IIRC - enough to put me off for a road car.
found these: http://www.automac.co.uk/product/Sam%20E30%20FL
i'm sure others will pipe up, or post in the trackdays section if anyone can recommend anything if you're keen.
nah, i "think" they're stronger and not prone to perishing like the standard rubbers so are uber reliable. you don't want a split hose when caning your car for hours on end. i've nver used them myself, i think e30 kits of 4or5 hoses costs about £150 IIRC - enough to put me off for a road car.
found these: http://www.automac.co.uk/product/Sam%20E30%20FL
i'm sure others will pipe up, or post in the trackdays section if anyone can recommend anything if you're keen.
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mrLEE30
- E30 Zone Team Member
- Posts: 6589
- Joined: Tue Jan 18, 2005 11:00 pm
- Location: Sweating buckets in Bahrain
i bet your standard ones are as old as the car in some cases, come back in twenty years and tell me the blue ones are any better - i will wager a very large bet they are not.not prone to perishing like the standard rubbers so are uber reliable
standard hoses are more than capable of coping with the pressure egenrated by the E30 cooling system, most likey if your hoses are failing they are very old or not OEM.
loogie your 2nd last post suggests you have over filled it, most E30's run toward the lower quarter of the expansion tank, only if the tank is dry and requires filling then you have a leak, and in your case it sounds like couild be the rad. further a small leak in the rad will be very hard to spot and the leak will mean the system does not get up to correct pressure and thus is will run hot, my reccomendation is to change the rad, and the viscous coupling on the fan at same time, when refitted subject the system to a pressure test and check for small leaks,
if the symptoms persist then i would start looking to the head gasket (by perfroming a compression check at first)
Thanks MrLee30, talking a lot of sense there, I only ever fill expansion tank to cold water level when engine cold, possibly on the track day didn't have time for the water to cool down, but tank was empty so had to put some in! I have been tightening the cap tighter more recently and the overflow to nearside wheel arch has not dripped at all since even on high temperatures although I have avoided running above half way on guage.
OMG! Have you seen the pictures they use to sell these "faclift" hoses..go on have a look what a f@*king mess!Adil786 wrote:i thought they were just coloured to look cool?
nah, i "think" they're stronger and not prone to perishing like the standard rubbers so are uber reliable. you don't want a split hose when caning your car for hours on end. i've nver used them myself, i think e30 kits of 4or5 hoses costs about £150 IIRC - enough to put me off for a road car.
found these: http://www.*Plug*.co.uk/product/Sam%20E30%20FL
i'm sure others will pipe up, or post in the trackdays section if anyone can recommend anything if you're keen.
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mrLEE30
- E30 Zone Team Member
- Posts: 6589
- Joined: Tue Jan 18, 2005 11:00 pm
- Location: Sweating buckets in Bahrain
if your tank is going dry then you have a leak (or faulty expansion cap)
The only real 100% way to find a cooling system leak is to do a pressure test, it is possible to look for the big leaks visually, but small amounts of water loss (i.e. less then half litre per hour or so of driving) will not be so obvious.
as for your rad it is not possible to fit a thicker rad (not enough space with the fan fitted)..what is possible is to fit a longer rad, as found on my car which has an offcial "tropical radiator" which is an OEM part, and keeps my cars all running cool depsite us seeing very very high temps here during the day....but is far as i am aware for UK track use your standard UK system is more than up to the job..if the system is working properly.
oh and what temps do we see?? Ok this is a one off day, mostly we ONLY see 45-50!
The only real 100% way to find a cooling system leak is to do a pressure test, it is possible to look for the big leaks visually, but small amounts of water loss (i.e. less then half litre per hour or so of driving) will not be so obvious.
as for your rad it is not possible to fit a thicker rad (not enough space with the fan fitted)..what is possible is to fit a longer rad, as found on my car which has an offcial "tropical radiator" which is an OEM part, and keeps my cars all running cool depsite us seeing very very high temps here during the day....but is far as i am aware for UK track use your standard UK system is more than up to the job..if the system is working properly.
oh and what temps do we see?? Ok this is a one off day, mostly we ONLY see 45-50!
I am melting just looking at that, hope you plenty cold ones in the fridge, I think maybe i wasn't tightening my Radiator expansion cap tight enough, I kept thinking i was going to thread the cap, now when I remove it I get a pleasant hiss of pressure release, also the water doesn't overlow out under the nearside wheel arch as it used to when hot, although I haven't really allowed her to get that hot, I am sure it was flowing at lower temperatures than I have been running. Thanks Iceman!
This makes me think that your cap may not have the rubber o ring on the underside which creates the seal.loogie1 wrote:I am melting just looking at that, hope you plenty cold ones in the fridge, I think maybe i wasn't tightening my Radiator expansion cap tight enough, I kept thinking i was going to thread the cap, now when I remove it I get a pleasant hiss of pressure release, also the water doesn't overlow out under the nearside wheel arch as it used to when hot, although I haven't really allowed her to get that hot, I am sure it was flowing at lower temperatures than I have been running. Thanks Iceman!
If you over tighten the cap these tear very easily. With the o ring in place you shouldn't have to tighten it so much that you worry about threading it.
These are sensations as hard to forget as they are to ignore.....
Thank you will check!clipper wrote:
This makes me think that your cap may not have the rubber o ring on the underside which creates the seal.
If you over tighten the cap these tear very easily. With the o ring in place you shouldn't have to tighten it so much that you worry about threading it.