Thermostat stuck open

[Bela]

Hi,

I bought a E39 528i 1997 on the weekend and was wondering if there were any overheating issues being hidden.

The car does not climb up to normal running temp, the temp gauge is sitting in the cold range (just above the cold marker) all the time, whether local driving or motorway.

This is a classic thermostat being on stuck open position.

Any feedback will be great.

Thanks

[scallyally]

I doubt if there is a thermostat in there!

[Brianmoooore]

528i changed from a conventional 'stat to an electrically controlled one, somewhere around that time.
If it's a conventional 'stat (and it's still there) one side of the bridge piece that holds the works in place will probably have broken. Genuine BMW 'stats are notorious for this.
If you have the electric 'stat, like most things where electronics has replaced simple mechanical systems, they work much better while they work, but are much less reliable. Just had to replace one on my 528i.

[steve_k]

if it's still got a mechanical stat, it could be stuck open or someone has drilled it to try & cure a hot running issue.

or as brian says, if it's a leccy one it's probably gone belly up.

[Bela]

Thanks for the feed back, the engine is a pre tech update model if that makes any difference. The heating is working in the cabin. Although taking a lot longer than normal.

[Bela]

Done, the water pump, thermostat and housing. All working fine now for the last two weeks.

The thermostat was stuck open.

Thanks for all the help.