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Coolant leaking from thermostat housing.

Posted: 02 Sep 2025, 18:07
by F41XTH
I've finally had time to identify where the coolant is leaking out from, it appears to be between the thermostat housing and the block. As seen in these photos, it's been eating away at the shield for some time.

I tried to tighten the bolt but didn't want to force and snap it. Do I get a new housing? Just remove, clean and reseal the existing one?

It's only a minor inconvenience right now, but we all know that one 20 minute job turns into a 5 day ordeal if a bolt snaps off

Re: Coolant leaking from thermostat housing.

Posted: 03 Sep 2025, 12:41
by Aidan
remove and inspect and then probably clean and reseal, the o ring isn't expensive so expect to replace. Overtightening the bolts can crack the housing, 10Nm I think is enough. Corrosion of the block at the mating face can be an issue.

Are you sure it's not coming from any of the hose connections ? Jubilee clips aren't the best for these connections, originally they were sprung clamps specifically sized for the job, but they often get damaged or lost or are too rusty to want to reuse

Re: Coolant leaking from thermostat housing.

Posted: 03 Sep 2025, 14:21
by F41XTH
Possibly. It's hard to get a proper look. It slowly weeps out from the bottom but I just can't identify the source point for sure.

I do need the van on weekends so I'm slightly reluctant to try to remove the housing in case it breaks or the bolts snap. Should also probably have a replacement on hand before even attempting to remove.

I'll try and get a look from the top down of this weather ever breaks