Air Con: 70: Heating poor after replacing leaking core matrix

[SteveSarre]

Hi Arnold,

You have probably done it already, but soak the bolt and its hole with your favourite penetrating fluid. That will often help - sometimes giving it a few days soak will make a big difference.

Are you able to drill into the centre of the bolt, to hollow it out? Use a small bit. You are not trying to remove the bolt by drilling, but sometimes that relaxes internal pressure enough to make a difference. eg a 2mm or 3mm bit. Drill as centrally as you can in case you later want to drill out with a larger bit. I would make a slight countersink using a large bit, being guided by the stripped torx recess, then proceed with the small bit.

Are you using a 13mm socket (preferably a 6 point), and are you using an impact driver to drive the 13mm socket? That would be a better option than a spanner.

As mentioned before, as a last resort you can remove the lower thermostat housing from the block, then deal with the seized bolt "on the bench". But having had a quick look, I can see that you may have to remove other stuff (eg power steering pump etc depending on your model) , so it is not trivial.

Hope that helps,
Steve

[Luxobarge]

Another tip when trying to remove stubborn bolts, is to initially try and tighten it. If there's any movement at all, this will help to break the corrosion bond that's causing it to seize, without damaging the faces of the hex that you'll need when undoing it. Then try to undo it.

Sounds counter-intuitive, but I've had this work MANY times.

[Arnold Layne]

Thanks for all the replies. I've replaced the thermostat, and I've immediately noticed that the car gets up to operational temperature quickly and most importantly - Stays there! Unfortunately it hasn't cured the poor heating inside the cabin, so I have to conclude that I bought a bad heater core off ebay. I've called Volvo and I'm not surprised that an OEM heater core is no longer available from them, but I've found one on ebay, at about £360! The part number is 9144221. Is there a good replacement that works, that anyone can recommend?

Thanks in advance

[Luxobarge]

I bought mine from PFV online, can't remember what make it is but it works fine and was a LOT cheaper than that!

[Derek UK]

I think the Mahle Behr ones are OK. Comments welcome.
This one is half the price of the second link

https://arks4cooling.com/product/mah...ger-ah106000s/

https://www.autodoc.co.uk/mahle-original/15288604

I need one too so I'm also after good info.