Howdy Folks,
This is a top notch site that definitely enhances the z owning experience so thankyou to all contributors!- my z3 has been off the road for a few months but when I run the engine for a few minutes the temp gauge goes all the way to hot v quickly, the engine overheats but the radiator/header tank is stone cold! any pointers as to what this fault may be will be very much appreciated - I have recently gone thru the car cosmetically and basic maint but havent touched cooling system. Thankyou, Jeremy.
overheating z3...
Re: overheating z3...
Hi and welcome to the forum, Jeremy.
It sounds like the thermostat has failed in the closed position on your car, which would mean that the coolant stays within the engine and gets very hot and does not get pumped through the radiator to cool it down. The normal failure mode for Z3 thermostats seems to be to fail in the open position, which means that car takes a long time to warm up, however I note from your profile you have a facelifted 1.9, which I think will have an electric thermostat, so this may fail in a different way than the mechanical ones. The only other possibility I can think of at the moment is waterpump failure, which would mean that the coolant would not be being circulated at all, though I'm not just sure what other symptoms to look out for that would tell you that was the case.
Hope you get it sorted soon. I'm sure there will be some other ideas posted shortly.
Cheers R.
It sounds like the thermostat has failed in the closed position on your car, which would mean that the coolant stays within the engine and gets very hot and does not get pumped through the radiator to cool it down. The normal failure mode for Z3 thermostats seems to be to fail in the open position, which means that car takes a long time to warm up, however I note from your profile you have a facelifted 1.9, which I think will have an electric thermostat, so this may fail in a different way than the mechanical ones. The only other possibility I can think of at the moment is waterpump failure, which would mean that the coolant would not be being circulated at all, though I'm not just sure what other symptoms to look out for that would tell you that was the case.
Hope you get it sorted soon. I'm sure there will be some other ideas posted shortly.
Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
- BladeRunner919
- Joined: Fri 17 Feb, 2012 20:18
- Posts: 2225
Re: overheating z3...
Could possibly be a blocked radiator too, but I'd start with Robert's suggestions and take it from there. I assume the basics, like coolant level, are ok and that there's no air in the system, as far as you can tell?
-
- Joined: Fri 19 Jun, 2009 10:27
- Posts: 2093
- Location: Daglan, France
Re: overheating z3...
Is the cylinder head really very hot, or is it just a guage malfunction?
A Z3 is not just for Christmas - it's for life!
Re: overheating z3...
U can also check the hoses that go to the radiator...
If they are cold then there is probably a problem with your thermostat...
If they are cold then there is probably a problem with your thermostat...
Re: overheating z3...
Cheers Chaps,
Definitely some handy hints to try out so thankyou to all respondees - is that a word?? the cylinder head gets very hot so will check the hoses and the thermostat, now I come to think of it when the car was last on the road the heater seemed very reluctant to emit any noticable heat so maybe this would suggest the thermostsat is faulty (Major!), yes my z3 is year 2000 engine 1.9 and I absolutely love it, had it for several years now and before this had a Z4 which although has a very nice interior the sharp handling just isnt suited to Dorsets leafy lanes. How would I best check for or remove air from the cooling system please before I start disassembling the flux capacitor...
Regards all, Jeremy.
Definitely some handy hints to try out so thankyou to all respondees - is that a word?? the cylinder head gets very hot so will check the hoses and the thermostat, now I come to think of it when the car was last on the road the heater seemed very reluctant to emit any noticable heat so maybe this would suggest the thermostsat is faulty (Major!), yes my z3 is year 2000 engine 1.9 and I absolutely love it, had it for several years now and before this had a Z4 which although has a very nice interior the sharp handling just isnt suited to Dorsets leafy lanes. How would I best check for or remove air from the cooling system please before I start disassembling the flux capacitor...
Regards all, Jeremy.
Re: overheating z3...
Unless you have had to drain the system recently there shouldn't be an airlock in system. If you check the expansion tank is full to the correct level and squeeze the top radiator hose a few times with the filler cap off you should see the water going up in the expansion tank.
I would think it is the thermostat or the water pump. BMW ones of your age had a plastic impeller which didn't fail by breaking up but sometimes came detached from the drive shaft so everything spins ok but the impeller does not go round.
To check both is a full drain and remove so you may as well replace both, flush the whole system through and refill with new anti freeze or ask your local garage to do it.
I would think it is the thermostat or the water pump. BMW ones of your age had a plastic impeller which didn't fail by breaking up but sometimes came detached from the drive shaft so everything spins ok but the impeller does not go round.
To check both is a full drain and remove so you may as well replace both, flush the whole system through and refill with new anti freeze or ask your local garage to do it.
Brian
3.0I Topaz Blue
2000 E36/7 Z3 3.0i
2016 F31 335d
2015 F21 118i
3.0I Topaz Blue
2000 E36/7 Z3 3.0i
2016 F31 335d
2015 F21 118i
Re: overheating z3...
Thanks Brian,
That all seems to make sense, day off for me tomorrow so thats the mornings entertainment taken care of - will see what I can glean from the knowledgebase in a bit and take it from there. Off to the shed to dust off my mole grips AND my claw hammer!! Should do the trick...
Cheers, Jeremy.
That all seems to make sense, day off for me tomorrow so thats the mornings entertainment taken care of - will see what I can glean from the knowledgebase in a bit and take it from there. Off to the shed to dust off my mole grips AND my claw hammer!! Should do the trick...
Cheers, Jeremy.
Re: overheating z3...
The combined fact that water wasn't previously getting pushed around your heater and is now not apparently even being pushed around the radiator, I would have a £1 each way bet (last of the big spenders ) that it is the water pump. I've been changing thermostats since the 1970s and only ever experienced ones that stick open and result in colder running.
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6436
- Location: Johannesburg
Re: overheating z3...
My 10p worth.....since you're doing the thermostat, you may as well change the thermostat housing to an aluminium one. The OEM housings are made of a hard plastic, which also becomes brittle over time and may crack when you re-fit and torque the bolts. There are waterpumps available with aluminium impellers vs the OEM plastic, which will ensure a longer life. Finally, only use distilled water when you re-fill the system...it'll prevent any scale build-up in the motor etc. The Thermostat housing will also need a new gasket and some gasket sealant will give you peace of mind too...