Block to heater hose size

toopy

Club Member
Im replacing my screw in coolant outlet stub on the block, is that what its called?! that takes coolant to the heater inlet bulk head pipe.

Anyway the diameter of the pipe is 16mm excluding the raised ridge/bead, my silicone hose is 16mm ID and slips on easily, a bit to easily!
Whats the diameter of the OEM hoses? I can get 13mm ID silicone hose but with the bead on the pipe to get past would they be over stretched and deteriorate quicker?

My existing arrangement has started weeping, the hose is 16mm ID already, but i think the leak is more to do with corrosion on the old pipe/stub than the actual hose.

Also what sealant should i use on the threads when i fit the new stub
 

jonbills

Membership Secretary
Site Administrator
On the block or on the head? I can't think of one on the block.
I have 16mm or 5/8" heater hose on mine and it's just right.
Maybe the problem is the silicon hose?
 

jonbills

Membership Secretary
Site Administrator
That's the one I was thinking of. I'm sure Nissan will have used 16mm hose. 5/8" hose should be in theory every so slightly snugger.
 
Last edited by a moderator:

Farmer42

Club Member
Just so happens that I have an OEM hose sat in the garage waiting for me to get motivated to fit it to replace my current 'bodge'. Part no. B7181-N3100.

It's 16mm. I used plumbing PTFE tape on the threads of the 'stub' that attaches to the cylinder head when I renewed mine & it works fine.
 

toopy

Club Member
Just so happens that I have an OEM hose sat in the garage waiting for me to get motivated to fit it to replace my current 'bodge'. Part no. B7181-N3100.

It's 16mm. I used plumbing PTFE tape on the threads of the 'stub' that attaches to the cylinder head when I renewed mine & it works fine.

Great, thanks for that :thumbs:
 
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