leaking engine coolant

[Z4 Spring lane]

Engine losing coolant. No white smoke from exhaust. Car running smoothly and engine not over heating. Had no problem before putting into winter storage. Filled up radiator when a got Z4 out of garage but has run dry with in a month with little use. Help please.

 

[Keyper]

Have you checked the expansion tank, its located on the the right hand side of the Rad, they tend to crack when the thermostat goes on them, well they do on the E85 anyhow :|

 

[GuidoK]

Yes, expansion tank, thermostat housing and the temperature sensor o ring (sensor sits an inch or so from the thermostat) are known leaky points.

Leaks at the expansion tank can be hard to find. (and as said mostly only leak when the system is warm/under pressure)

 

[Keyper]

Heres mine for an example, you just can't tell until your engines upto temp

 

[Z4 Spring lane]

Thanks chaps. Is it expensive to get sorted?

 

[Keyper]

Thanks chaps. Is it expensive to get sorted?

If thats deffo the problem, find a couple of ebay links below that covers the E85 (2004)

I replaced both at the same time, i went on youtube for the video's, trust me i'm no mechanic lol, but managed it in a couple of hours

http://www.ebay.co.uk/itm/Oil-Cooler-Radiator-Expansion-Tank-Thermostat-for-BMW-E46-E53-E83-E85-1711143736-/171714395458?pt=LH_DefaultDomain_3&fits=Plat_Gen%3AE85&hash=item27faf9bd42

http://www.ebay.co.uk/itm/BMW-3-SERIES-E46-X3-E83-X5-E53-Z4-1998-2008-EXPANSION-WATER-COOLANT-TANK-/351252296006?pt=LH_DefaultDomain_3&fits=Plat_Gen%3AE85&hash=item51c844b146

 

[GuidoK]

Afaik that expansion tank in your ebay ad doesnt fit the z4 properly.
The z4 has a tank with a different partnumber than the e46.
And that other part is I think a thermostat to regulate the (automatic) transmission cooler, not the engine's thermostat.

 

[Maniac]

E89 section?

 

[Keyper]

yeh sorry giving my experiance on an E85

 

[Maniac]

yeh sorry giving my experiance on an E85

More for the OP tbh as I'm not sure even tho he's posted in e89 if he's talking e89z

 

[GuidoK]

He has a 2.2 e85
http://www.z4-forum.com/forum/viewtopic.php?f=11&t=75170&p=1109304#p1109304

 

[Keyper]

yeh sorry giving my experiance on an E85

More for the OP tbh as I'm not sure even tho he's posted in e89 if he's talking e89z

Your right it's a E85

 

[ben g]

My coolant leaked from the thermostat housing and expansion tank, as others have said.

I paid about £80 for an OEM tank, but bought an aftermarket thermostat from eurocarparts. Been fine ever since (couple of years).