E36 328i cooling system question
Discussion
Hi everyone
I've had my 328i Sport Touring a couple of months, and in warm weather and heavy traffic on Friday with the AC on a hose split in the cooling system causing the car to overheat. I immediately switched it off and got the RAC to drop me at a local garage who are currently fixing the hose.
I asked the garage whether they think there might be something else wrong with the cooling system that caused the problem, they reckoned it's just that it was an old hose and should be fine. But wondering whether anyone here would be immediately suspicious of something else which could make another weak link in the chain go again before too long?
I may be wrong but I don't remember hearing the fan engaging when it was hot. Any ideas why might that be?
Sorry for the essay, but really appreciate any help as I'm absolutely loving the car otherwise!
I've had my 328i Sport Touring a couple of months, and in warm weather and heavy traffic on Friday with the AC on a hose split in the cooling system causing the car to overheat. I immediately switched it off and got the RAC to drop me at a local garage who are currently fixing the hose.
I asked the garage whether they think there might be something else wrong with the cooling system that caused the problem, they reckoned it's just that it was an old hose and should be fine. But wondering whether anyone here would be immediately suspicious of something else which could make another weak link in the chain go again before too long?
I may be wrong but I don't remember hearing the fan engaging when it was hot. Any ideas why might that be?
Sorry for the essay, but really appreciate any help as I'm absolutely loving the car otherwise!
VicarCharlie said:
Hi everyone
I've had my 328i Sport Touring a couple of months, and in warm weather and heavy traffic on Friday with the AC on a hose split in the cooling system causing the car to overheat. I immediately switched it off and got the RAC to drop me at a local garage who are currently fixing the hose.
I asked the garage whether they think there might be something else wrong with the cooling system that caused the problem, they reckoned it's just that it was an old hose and should be fine. But wondering whether anyone here would be immediately suspicious of something else which could make another weak link in the chain go again before too long?
I may be wrong but I don't remember hearing the fan engaging when it was hot. Any ideas why might that be?
Sorry for the essay, but really appreciate any help as I'm absolutely loving the car otherwise!
Provided your temp gauge didn't drift into the red then I wouldn't be too worried. Chances are it was just the perished hose that resulted in coolant loss and the resulting overheat. I've had my 328i Sport Touring a couple of months, and in warm weather and heavy traffic on Friday with the AC on a hose split in the cooling system causing the car to overheat. I immediately switched it off and got the RAC to drop me at a local garage who are currently fixing the hose.
I asked the garage whether they think there might be something else wrong with the cooling system that caused the problem, they reckoned it's just that it was an old hose and should be fine. But wondering whether anyone here would be immediately suspicious of something else which could make another weak link in the chain go again before too long?
I may be wrong but I don't remember hearing the fan engaging when it was hot. Any ideas why might that be?
Sorry for the essay, but really appreciate any help as I'm absolutely loving the car otherwise!
With regard to the fan not engaging this could be a failed viscous fan coupling. I had it fail on my previous car (93 320) but the one on my current car (99 328 sport) is still going strong at over 191k (along with everything else cooling related minus the radiator bleed screw). I'm not 100% but I'm pretty sure it should be running when the engine is up to temp.
Personally I wont go down the preventative replacement route on the cooling system until leaks or other problems arise, however If I owned a pre 98 model I would swap out the water pump for the revised version with a metal impeller instead of plastic. I had the water pump fail on my 93 320.
Thanks for the replies guys.
Looks like thermostat and water pump were replaced (metal impeller) in 2013.
The temp did get into red very briefly as I limped into the petrol station... I agree I think it was the hose bursting and losing the coolant that caused it to overheat, I guess I'm just wondering if there's something else that caused the hose to split?
It's a 98 car with 130k
Looks like thermostat and water pump were replaced (metal impeller) in 2013.
The temp did get into red very briefly as I limped into the petrol station... I agree I think it was the hose bursting and losing the coolant that caused it to overheat, I guess I'm just wondering if there's something else that caused the hose to split?
It's a 98 car with 130k
Could be a lot of things.
But I'd get that hose replaced and make sure the viscous fan and the electric fan for the AC both work. There's all kinds of b
ks spouted about it* but if the coupling looks black and nasty, replace it. It's black and grimy because the oil has leaked out (attracting dirt) and is therefore useless. If it's the original it'll be shagged by now anyway. A Borg and Beck one from ECP is fine. The electric fan needs to work also - with it running, switch on the AC and the fan should come on. Chances are it's seized or the resistor is borked.
Don't be tempted to do the 'fan delete' either where the viscous is removed in vain attempt to gain 3 bhp at 6000 rpm. It'll run too hot and the AC fan will be doing its chuff trying to cool it down.
But I'd get that hose replaced and make sure the viscous fan and the electric fan for the AC both work. There's all kinds of b
ks spouted about it* but if the coupling looks black and nasty, replace it. It's black and grimy because the oil has leaked out (attracting dirt) and is therefore useless. If it's the original it'll be shagged by now anyway. A Borg and Beck one from ECP is fine. The electric fan needs to work also - with it running, switch on the AC and the fan should come on. Chances are it's seized or the resistor is borked.Don't be tempted to do the 'fan delete' either where the viscous is removed in vain attempt to gain 3 bhp at 6000 rpm. It'll run too hot and the AC fan will be doing its chuff trying to cool it down.
- 'stick a rolled up newspaper in the fan' is the best one. Priceless.
eztiger328 said:
Provided your temp gauge didn't drift into the red then I wouldn't be too worried. Chances are it was just the perished hose that resulted in coolant loss and the resulting overheat.
With regard to the fan not engaging this could be a failed viscous fan coupling. I had it fail on my previous car (93 320) but the one on my current car (99 328 sport) is still going strong at over 191k (along with everything else cooling related minus the radiator bleed screw). I'm not 100% but I'm pretty sure it should be running when the engine is up to temp.
Personally I wont go down the preventative replacement route on the cooling system until leaks or other problems arise, however If I owned a pre 98 model I would swap out the water pump for the revised version with a metal impeller instead of plastic. I had the water pump fail on my 93 320.
I replaced the waterpump on my 98 - looked plastic (black one):With regard to the fan not engaging this could be a failed viscous fan coupling. I had it fail on my previous car (93 320) but the one on my current car (99 328 sport) is still going strong at over 191k (along with everything else cooling related minus the radiator bleed screw). I'm not 100% but I'm pretty sure it should be running when the engine is up to temp.
Personally I wont go down the preventative replacement route on the cooling system until leaks or other problems arise, however If I owned a pre 98 model I would swap out the water pump for the revised version with a metal impeller instead of plastic. I had the water pump fail on my 93 320.
VicarCharlie said:
Thanks for the replies guys.
Looks like thermostat and water pump were replaced (metal impeller) in 2013.
The temp did get into red very briefly as I limped into the petrol station... I agree I think it was the hose bursting and losing the coolant that caused it to overheat, I guess I'm just wondering if there's something else that caused the hose to split?
It's a 98 car with 130k
I've read that the coolant temperature gauge on the E36 is apparently non-linear in that a small movement above normal operating temperature can signify a significant increase in engine temperature, so your motor might have got quite hot. I understand the M52 engine doesn't like being overheated, so maybe get a sniffer check done to check for head gasket failure, which could be pressurising the cooling system?Looks like thermostat and water pump were replaced (metal impeller) in 2013.
The temp did get into red very briefly as I limped into the petrol station... I agree I think it was the hose bursting and losing the coolant that caused it to overheat, I guess I'm just wondering if there's something else that caused the hose to split?
It's a 98 car with 130k
Having said that, my 328 blew its expansion tank with a previous owner but after replacing the rad and tank it seems to be running fine. Mind you, I stuck a new water pump and thermostat/housing on it to be sure.
Also check the fans as others have stated. My local indy informs me the electric air con fans tend to seize, being quite exposed to water coming through the grille etc.
My previous E36 323i had a viscous fan replacement, also a water pump went and I had the thermostat changed at the same time. However they did not vent the system properly and it started to overheat again, but that was easy to fix. I recall that apart from those specifically overheating episodes, when warmed up the temp gauge was always rock solid on the mid-point. I loved my E36, just traded in after 19 years for a 335d, which is extremely competent, but the E36 was extremely competent (it did eat springs and bushes though!)
BGarside said:
I've read that the coolant temperature gauge on the E36 is apparently non-linear in that a small movement above normal operating temperature can signify a significant increase in engine temperature, so your motor might have got quite hot.
I've not read this in its entirety but it talks about recalibrating the temp gauge in the e46 to remove the buffer effect:http://forum.e46fanatics.com/showthread.php?t=1013...
It might be applicable to the e36 - I for one would like a more accurate temp gauge.. any brave soul up for trawling through it to see if it's been discussed?
Coolant temp sensors aren't the most reliable things either, (well on the M44 not sure about the 6 pots though?) worth doing for the sake of a few quid.
You can happily remove the viscous and replace with a decent electric one, we do this in the Compacts without issue!
Not sure it's worth the 1 pony it releases but on a race car its one less thing to go wrong!
You can happily remove the viscous and replace with a decent electric one, we do this in the Compacts without issue!
Not sure it's worth the 1 pony it releases but on a race car its one less thing to go wrong!
Another favourite leak on the E36 based cars is the expansion bottle on the side of the rad..
When they get old the plastic gets deformed and they start leaking from the bottom seal.
It's a very easy job the change and takes about 20 minutes, I recently did one on my Z3 the expansion bottle is cheap as chips and easy to get hold of.
I think I paid £10 for a NOS genuine BMW one off eBay and it comes with the new rubber seals also fitted.
It's never a bad thing to change the odd bit of the cooling system anyway as at least you know you can flush the system through at the same time and add some fresh coolant as I think it's supposed to be renewed every 3 years anyway.
Make sure you use the correct coolant though, I think it has to be Bmw approved and is green in colour.
When they get old the plastic gets deformed and they start leaking from the bottom seal.
It's a very easy job the change and takes about 20 minutes, I recently did one on my Z3 the expansion bottle is cheap as chips and easy to get hold of.
I think I paid £10 for a NOS genuine BMW one off eBay and it comes with the new rubber seals also fitted.
It's never a bad thing to change the odd bit of the cooling system anyway as at least you know you can flush the system through at the same time and add some fresh coolant as I think it's supposed to be renewed every 3 years anyway.
Make sure you use the correct coolant though, I think it has to be Bmw approved and is green in colour.
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