360 Thermostat housing whoopsie

Things are not going so smoothly. I felt the car needed a new thermostat, so I bought one last week. I took the car to work yesterday and a steady cruise down the motorway highlighted that the old one was definitely borked. Temperature gauge only getting to 150-ish F. Turning the heater temp from min to max made near enough no difference to the air coming out the vents. So yesterday evening, it was out with the tools

Engine access hatch accessed:

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Old thermostat out. You can see daylight through it when it is supposed to be closed !!

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But then it started to go wrong. One of the bolts securing the thermostat housing was reluctant to go back in. I persevered and used a bit more force than should be needed, it didn’t feel cross threaded, I know what cross threaded feels like ! But about halfway down I decided enough and backed it right out to have another look. It has party pulled the insert out:


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Dammit.

These cars are actually pretty well engineered. Other cars I’ve had, this would simply be a thread in to the aluminium. Here there are factory fitted helicoils. So I think a bit of galvanic corrosion has squeezed everything and it just happened to grip the bolt more than the housing. But still. Dammit..

There’s no space to work on it in situ so I think I’m going to have to remove the whole water pump housing now.

 

Is that possible in-situ ? I'll give it a try but it looked pretty tight or access.

 

The engine hatch was fine to get the thermostat out, I don't fancy disturbing the plenums. Plus you must have much longer arms than I do if you can reach the thermostat from outside the car !!

Back to the helicoil question, I've ordered one of these. Looks like it'll work in a restricted space. I don't need to drill it out, I just need to chase the threads and put a new insert in, these tools will work with a 1/4" socket on them.

https://www.voelkel-shop.com/en/v-coil-rapid-thread-repair-kits-6-x-1-0-1-5d-volkel-04310-m6.html


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I can now close this out, thankfully

It didn’t turn out too difficult in the end apart from access being a bit awkward. A stud remover was adequate to grab the old coil and wind it out. The helicoil kit worked perfectly. I wasn’t planning on using the drill from the kit but the tap wasn’t initially keen to go in and gently clearing through with the drill helped. The new coil wound in easily just using my fingers.

Thumbs up to V-Coil ! Seems to be decent kit.

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Here's my tool tip for the thermostat housing bolts. A long hex bit, a 1/4" ratchet, and some tape around the end to stop it falling out. This allows you to move the ratchet up/down to wherever there's clearance to swing it around.

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So then we had the fun of bleeding the cooling system. Long story but the takeaway is this - do not engage the "STOP" button on the heater controls. It doesn't just stop the a/c compressor, it also stops the heat, and you simply get ambient air regardless of the setting on the dial. Whoever thought that was a good idea owes me two hours of my life that I spent trying to get hot air out of the heater. I think the system had actually bled itself.

So all fine now. The engine sits at ~175 normally and creeps up to ~200 when moving slowly or stopped. Before it was dropping almost right down to 140 when moving.