Heater hoses flow direction

Post by **taxi** » 28 Jan 2021, 09:29

Hi! I'm working on a little project on my V70 -2000, and I can't figure out which hose (upper or lower) in the engine bay by the firewall that feeds into the heater element.
Is there a non-messy way of discovering the coolant direction?

Thank you and have a great day!

Post by **Sveedy** » 28 Jan 2021, 10:49

Not sure what you mean by " non-messy " since your taking off the two heater hoses, which would cause a mess. That said, if you have both hoses disconnected then I would think that you could blow air into the system from the coolant reservoir tank and see which of the heater hoses expels a little bit more coolant. Or if you drained the system then blew air in you could then maybe feel for the air coming out of the inlet hose. Last idea would be maybe using a handheld IR temperature sensor that would show which of the two hoses gets hot first, with that hose being the inlet hose.

Post by **taxi** » 28 Jan 2021, 12:04

That last idea, I like it! Thank you very much, sir!
I will put clamps on the two hoses and connect a fuel heater, with, in theory, very little spill.
Thank you again!

Post by **BEJinFbk** » 28 Jan 2021, 13:26

Please post back with your results!

I can’t explain why I’d like to know,
( My brain is funny like that... )
it just seems like something that
would be helpful later. Probably
when something has gone terribly
and abruptly wrong and one finds
oneself in the “Fog of Volvo War”.

Post by **abscate** » 28 Jan 2021, 20:16

Even easier.

One hose comes off the back of the cylinder head ( actually just below it on the block)

That’s the hot coolant flow IN to the heater core

The cooler side connects to the water pipe and heads back to the pump to be circulated through the radiator again.

Both hoses will fit into the upper and lower coupler positions, so upper and lower aren’t reliable markers. Stock configuration is upper Is hot in, lower is cooler out, relative to the heater core

Post by **taxi** » 28 Jan 2021, 21:33

Thank you, now I can't mess this up! Famous last words..
I promise to try to remember to post back. This was difficult at younger age, it will be even more difficult now, but I will really try.

Post by **abscate** » 29 Jan 2021, 03:18

Found this on the web, too

Missing ,the later RN biscuit style oil cooler and coolant flow

Post by **taxi** » 30 Jan 2021, 23:36

Diesel fuel heater is now mounted under the battery. Today I will connect water hoses and a diesel tank and hopefully try it out. I'll be back soon.

Post by **taxi** » 02 Feb 2021, 10:53

A few delays later:
It's working! Eberspächer 4,5 kw, a simple switch next to the ignition key turns it on.
I did a "inline coolant connection", where full flow goes through the fuel heater at all times, and I'm a bit curious as to how long that will hold. The low coolant warning works, so I guess I can sleep for now.
Separate diesel fuel tank is placed in the engine compartment, NOT next to exhaust.

What do you think about the coolant full flow-thing? Do you think it will last? According to eberspächer it is an acceptable connection method, but it seems like that's for a separate waterpump. Mine has water and diesel pump built in to the fuel heater itself.

Thank you for your support!

Post by **BEJinFbk** » 02 Feb 2021, 15:04

Have you got a link for that heater?
Asking for a Friend...

( Currently -14 F )