[Hu Flung Dung]

Does anyone know off the top of their head (or otherwise) what the ID of the coolant hoses are? Specifically the hose that goes directly into the firewall to the heater core.
My car has a valve JUST before the firewall in the engine compartment that I close in the summer to keep heat out of the cabin (it was there when I bought the car).
I closed it yesterday only to find that it leaks like hell now! I'm planning on picking up another today after work (it appears to be just a regular plumbing valve) but not sure what the inner diameter of the hoses are. I'm driving the car so I can't take the valve out to compare while shopping! Any help appreciated.
Thanks all -
HFD

 

[john-w]

I think it's 5/8ins.... Is that about 18mm??

 

[Marcos]

I think it's 5/8ins.... Is that about 18mm??

1inch = 2.54 cm, thusly:

5/8 = 1.587 cm which is pretty close to about 18mm, give or take 2mm (or .078 inches)

 

[Matthew]

I measured a spare (used) heater hose from the garage. Assuming I correctly remembered how to read a vernier gauge, the hose size was 24.46mm ID. I also measured the OD at 34.64mm with hose wall thickness at 4.72mm which gives a calculated ID of 25.2mm.

I suspect the ID is supposed to be 25mm.

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[Marcos]

I measured a spare (used) heater hose from the garage. Assuming I correctly remembered how to read a vernier gauge, <snip>

Matthew! Of all people, you should know that you need a special caliper to measure flexible materials! :cheesy: Probably the most accurate reading is the wall thickness... your assumptions are right, tho.

(In jest without intention to offend, hope you get it.)

 

[ProfZ]

Something doesn't add up here, gentlemen

I just measured a factory-fresh (unstretched) heater hose, and got exactly 7/8 inch (= 22mm) for the inner diameter.

 

[Marcos]

Probably swell from being in the engine compartment and stretch from being presurized would account for the discrepancies in Matthew's readings... and being that Hu Flung Dung's is a... uh... special job where this valve probably will have to be fitted with hose clamps, the differences could be irrelevant.

I'm just wondering, though, what the valve is there for and a) why should it be replaced, b) wouldn't replacing the hose with an original (=sans valve) or straight patching it with a flexhose be better?

 

[Hu Flung Dung]

I'm just wondering, though, what the valve is there for and a) why should it be replaced, b) wouldn't replacing the hose with an original (=sans valve) or straight patching it with a flexhose be better?

Well, the valve was there when I bought the car from the original owner's son..he said his mother made his father, a Saab mechanic, put in there so that in the summer it could be closed to keep heat out of the cabin.
I closed it last summer and I DID notice a difference...there was no hot air seeping out from the vents (I keep the vents on recirc but there always seems to be a *slight* bit of air seeping out.)
This year when it started to get warm outside and I closed it, the top of the valve at the shaft started leaking coolant. It doesn't leak when the valve is open, only when closed. It's a cheap plastic valve so I figured I'd replace it. It's just hoseclamped smack in the middle of that heater hose.

 

[Marcos]

I keep heat out of the cabin by turning the heat control switch to the blue... I thought that kept coolant from circulating through the heater - which is what it seems this valve is doing.

 

[Hu Flung Dung]

Re

Yeah, I thought that did too...mine is on 'blue' also.

Heat still comes into the cabin...not a lot, but noticeable.

This valve outside the firewall seems to take care of that.