This coolant line doesn't seem to exist...

[dontfeedthevolvo]

Okay so there's this coolant line that is under the upper radiator hose, that runs out of the thermostat. It has been seeping for a while, leading me to have to top up on coolant every few months. I have been able to live with it, but I would like to replace it before it fails. I have searched all over the engine diagrams on Volvo Parts Webstore and Volvo OEM Parts Direct trying to find the part number for this hose.

Does anyone know what part # the hose is or what I could replace it with?

https://drive.google.com/file/d/1lgmV9sYkQsxhokf1oRL-j7FQKuaOXuZZ/view?usp=sharing
https://drive.google.com/file/d/1iTjpIEPeTnoGmXoru5yEtYW3azbwd4kS/view?usp=sharing

[Astro14]

It’s actually part of your PCV system and sold with the big PCV hose that connects to your intake manifold and the driver side of the cylinder head.

It’s part of this kit, for example:

https://www.ipdusa.com/products/4990/115030-pcv-breather-system-kit-2003-2004-c70-s60-v70-xc70-xc90-turbo-5-cylinder-genuine-volvo-115030

[dontfeedthevolvo]

Do you know if there's a way to buy that section by itself? I'm not too keen on spending $230 on the entire pipe lol

[Astro14]

I don’t think it’s available separately.

But it’s standard heater hose. Nothing special. And the bend is small enough that bulk hose could be used.

That said, I would get an intake manifold gasket, sealing rings for the PCV fitting, and remove the manifold before attempting to replace that hose with a length of bulk hose.

Clean up the mating surfaces well. Use Oetiker clamps, they work better than hose clamps.

[Xfingers]

Your coolant loss I don't think can be from that PCV hose since it's only carrying oily vapors and fumes from the engine block.

Is it the connection of the upper radiator hose above it that's leaking?
Check under the floormats on the driver/passenger interior wheel wells for dampness to see if your HEATER CORE may be leaking coolant.

[NTXC]

I revamped my entire cooling system in terms of hoses. Ended up with a small leak near the thermostat. As silly as it sounds, give your hose clamps a few tightening turns. Boy was my face red when I figured out that after a few heat cycles my upper radiator hose was juuuust loose enough to let coolant out overnight (pressurized) but not enough to produce a drip. That resulted in several additions of coolant before I tightened it again (looked real close and found coolant residue).

Not a drop since.

Always check your clamps first was the lesson learned.

[Astro14]

Your coolant loss I don't think can be from that PCV hose since it's only carrying oily vapors and fumes from the engine block.

Is it the connection of the upper radiator hose above it that's leaking?
Check under the floormats on the driver/passenger interior wheel wells for dampness to see if your HEATER CORE may be leaking coolant.

I have to disagree.

That hose carries coolant.

Coolant.

It carries coolant from the thermostat housing to the side of the head, where it bolts into the head water jacket via banjo bolt with two copper sealing rings.

The PCV tube is a tube within a tube. One for vapors. One for coolant.

The coolant keeps the tube warm, as the vapors travel to the intake pipe just prior to the turbo inlet. This keeps them from condensing (well, sort of, they still condense and sludge up over time).

So, because it carries coolant, that small hose could very well be your coolant leak.

[Xfingers]

Absolutely, Astro. Thanx for the correction.

The long PCV pipe that attaches to the engine block has a banjo fitting where coolant passes. As you said, "The PCV tube is a tube within a tube. One for vapors. One for coolant."
I try to be cautious about giving advice on this forum. Lesson learned!

[Astro14]

Well... having replaced that PCV hose on each of my cars, which entails getting a clamp on that little coolant hose by the thermostat, fitting the banjo bolt into the manifold, which takes a few dozen tries to align, clearing the wiring to get that other banjo bolt into the head, along with a dropped sealing ring or two, and at least half a dozen attempted combinations with a 10mm socket and 1/4” drive wobble extensions to get that last manifold bolt, I remember it all pretty clearly.

I love the P2 chassis. Great cars. But ugh, that PCV system...

[hoonk]

Do you know if there's a way to buy that section by itself?

The coolant hose is an unusual size, probably 10mm, I could never find that size and had to rig something the only time I tried to fix that w/out a new pcv pipe. 3/8 coolant hose is sold but is very tight . (3/8 in = ~9.5 mm)