Heater core leaking.

[balimatharu]

Hi.
I am back with a different problem.
The power steering is sorted out. Thanks to all.
When I was assembling my 250sl I serviced the controller valve. Just replaced the rubber seal. Didn’t do any pressure check on the core as had no problem with it.
Now after putting everything together I could see coolant dripping from left corner through the foam seal.
Does it mean that all has to be undone and remove the core. I am sure there is
no leak from the valve as I can view the the valve through the hole in the bulkhead.
Is there anything I should look into before I start dismantling the under dash.
Please comment.
Bali

[doitwright]

Aside from “leak stop” additives (usually only a temporary fix), if you are certain it is coolant and you are certain it is not leaking at the valve (visible through removable rubber cap in the engine compartment) then you likely have a leak in your core. Rare but possible.

[balimatharu]

Thanks for your reply.
Now I am thinking why didn’t I do it right. Should have pressure tested.
I have just put the dash together and now going to undo it.
Learnt a hard way.
Thanks again.
Bali

[doitwright]

I understand the frustration. Many have said the assembly process of a Pagoda starts with the heater core and the rest of the car gets built around it.

[Jordan]

Before you disassemble anything make sure all your hose clamps are tight and the hoses are not cracked.

[doitwright]

Before you disassemble anything make sure all your hose clamps are tight and the hoses are not cracked.

That is a good tip but I would think since the hose connections are in the engine compartment a leak there would not show up in the cabin.

Disconnect both hoses at the firewall in the engine compartment. Pressure test the core and check again. If you test with a pressure gauge, a drop on the needle will confirm your problem.

[balimatharu]

DoitWright.
That’s exactly what I did. I used car tyre inflator. Hermetically sealed both sides. I think this is the best suggestion.
Core removed. The leak was at the junction of the valve and the core. I have a heavy duty soldering iron and that did the job nicely. Checked at 25 psi submerged in water.
Jordan thanks for taking interest in this.

Bali