I did that on mine. One bolt you can thru-drill and sneak a nut on the bottom - problem solved forever. The other one I carefully drilled out and did a Heli-Coil (or similar) and saved the housing. 6mm IIRC. It was worth pulling the housing as it allowed me to clean it up on the rotary wire brush (think bench grinder) and get a clean surface under the hose.

I used the 1 5/8 gas hose and it fit's PERFECTLY. I suspect it's what they used from the factory except it's readily available. I cut mine with a hacksaw - works fine. I'm sure the silicone would work fine too but be REALLY careful that you don't cut it with the clamp - easy to do on silicone (voice of experience).

Dan

I think the hose is actually 40mm by the book, which is a hair under 1.5".

I just went to the local PEP boys, found a hose with a straight section the same diameter, and put it back on.

The factory clamps both had corroded screws so I put some BREEZE constant spring tension clamps on there.

One bolt was really rusty and should have been replaced. I think this comes from coolant leaking into the bolt hole. The other bolt was shiny.

So order new bolts and clamps and a new thermostat and gasket before you take it loose. And maybe all the other radiator hoses if they are old. Cheap insurance against a head replacement.

When I changed My Coolant Bypass Hose I found I had deep pitting on the Hose Nipples on both sides.

I wire brushed and scraped out the white corrosion down to the bare metal and filled the "pot holes" with JB Weld Epoxy (the slow curing one that can take the heat) and then I wrapped it with Masking tape the Epoxy would not run out and it would remain cylindrical.

When cured I filled in the any low areas and sanded it to the contour of the Hose Nipples.

No further issues since 2007.

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84 300D, 82 Volvo 244Gl Diesel