Thermostat housing leak

[alf885]

With reference to previous threads regarding coolant leaks during cold weather. I discovered a small leak from the blanking plug/bolt situated at the top of the thermostat housing on my '06. I removed the tank and traced the leak from the large "U" bend hose on the left side of the tank.

This problem has only surfaced during a cold spell here in the UK -6C again overnight and the leak has returned after I'd nipped up the plug/bolt yesterday. A copper washer is fitted and appears to be the location of the leak, there's no obvious crack or hole in the housing.

The tank will have to come off again!

Any experience anyone of a similar problem? Should I use a sealant to cure the problem? Will I need to drain down the system, remove plug and replace washer?

BTW How do you switch off the alarm before removing the battery, it's a Datatool S4?

alf

[alf885]

Items 9 and 8 is where the leak is coming from.

Alarm issue sorted, RTFI - Read the f****** instructions!

[iansoady]

That's the bleed screw, used to make sure you haven't got any air in the system. I always soften copper washers before reusing them - get them red hot in a gas flame then quench in water. The quench isn't necessary but does clean any crap off.

Dowty washers (with a rubber insert) are great for sealing things like this.

[alf885]

OK tank came off again and the leak had moved?

No longer coming from the bleed screw it was now coming from the large hose (no. 33 in diagram) connected to the housing. Yes, I should have checked those clips first time around but hadn't. I tightened them all by at least one full turn, suprising how loose they are, and all is well. alf

[iansoady]

The plastic the housing is made of is quite soft and I've heard of a couple of people distorting it by overtightening so it pays to go easy. Anyway, hope it's fixed now.

[alf885]

The plastic the housing is made of is quite soft and I've heard of a couple of people distorting it by overtightening so it pays to go easy. Anyway, hope it's fixed now.

Noted. I did wonder because they were all too easy to tighten and I only tightened the offending connection until it stopped leaking. Hope that's enough and not too much. Seems OK but I guess time will tell. Does seem a weak point though on the Tiger, do 955i S3's suffer the same? Thanks for the replies, alf.

[Boo]

Just had a similar problem to this. I may fit a short piece of thin wall pipe inside the plastic housing to help stop it crushing. Got to be worth a try!