Lower Rad Hose Keeps Leaking

WhatAmIDoing · Post by **WhatAmIDoing** » 27 Jan 2018, 15:25

A few months ago, I performed a coolant flush and replaced the expansion tank and heater core on my '98 S70 T5M. Overall, an easy job. The only problem I ran into was when I went to take the lower rad hose off. The hose clamp was badly rusted, and I snapped the head off with a screwdriver trying to loosen it. So I had to cut the clamp off which resulted in damaging the lower rad hose. Fortunately, the local autoparts store had one Dayco hose in stock that would fit my S70. Finished the flush, installed the new hose, all was well.

Hose began leaking at the upper and lower connections, so I tightened the clamps. That stopped the upper leak, but I'm still fighting the lower leak. Coolant appears to be seeping past the clamp on the lower hose where it connects to the radiator. Coolant does not appear to be leaking from the radiator. I keep tightening the clamp, but I'm scared to go much tighter fearing I'll tear through the hose or crack the inlet. The clamp was tightened with my two fingers as close to the head of the socket as possible, plus one full turn, and now many more quarter turns and still leaking.

I'm amazed the hose leaks at all considering how hard it was to get over the inlet. Leaks in warm or cold ambient temps, leaks with system pressurized and unpreasurized, did not notice any cracking on the inlet when I installed the new hose. Is this what I get for not buying a Volvo hose, or is there a trick I'm missing?

Post by **cn90** » 27 Jan 2018, 15:34

- Loosen the clamp.
- Twist the hose a bit to unseat it. Make sure it is all the way in.
- Rotate the clamps a bit so it bites a bit differently.
- Tighten it and see what happens.

PS: Make sure no old residual hose material is left behind on the rad outlet.

Post by **abscate** » 27 Jan 2018, 15:41

Coolant will seep on cheap hoses by permeating the core of the hose.

Are you getting a drip or is it just moist?

It might be a problem best left alone if you don’t need to add coolant

WhatAmIDoing · Post by **WhatAmIDoing** » 27 Jan 2018, 16:09

It is a pretty good drip. Enough to leave a 1-2 inch spot on the concrete, and on 2 occasions a nice puddle. I've had to top up on coolant about every 2 months. Wish I could say the aftermarket hose was cheap, but it cost more than a new OE hose on FCP. I just couldn't wait 4 days for a new hose. Only other thought I had was the expensive stainless steel hose clamp I bought keeps working itself loose.

cn90 wrote: ↑27 Jan 2018, 15:34 - Loosen the clamp.
- Twist the hose a bit to unseat it. Make sure it is all the way in.
- Rotate the clamps a bit so it bites a bit differently.
- Tighten it and see what happens.

PS: Make sure no old residual hose material is left behind on the rad outlet.

I tried this once, the hose was on so tight with the clamp off that I was afraid I would break off the inlet, but eventually the hose gave way. Admittedly, I could have cleaned the inlet better before installing, but the hose I destroyed was only 3-4 years old OE Volvo so I doubt it left much if anything behind. Will try this again.

crlande · Post by **crlande** » 27 Jan 2018, 19:23

Throw a second clamp on it.

Post by **abscate** » 27 Jan 2018, 20:00

Are you sure the radiator snout isn't cracked? That does suck but it would explain symptoms

Post by **wizechatmgr** » 27 Jan 2018, 21:53

You could apply some green or blue lock-tite on the clamp but I doubt it is working its way loose that quickly.

You could try ordering some Breeze CT clamps - they're a heck of a lot better than what is offered in most parts stores.

Post by **RickHaleParker** » 28 Jan 2018, 07:13

1. Pull the lower hose, get it clean and dry inside.
2. Place a thin but even coat of Room Temperature Vulcanizing silicone (RTV silicone) on the inside of hose, the depth of the inlet.
3. Reinstall hose, allow time for the RTVs to fully vulcanize.
4. Refill cooling system.

Post by **oragex** » 28 Jan 2018, 08:38

Which clamps are you using? Is it this type with 'protruding' teeth? See this video at 22:40 youtube.com/watch?v=3fEjbMpVSfo

The screw clamps can take so much force on them. At some point, the small teeth in the band will torn and the screw will start slipping and loose pressure. Loosen it a bit and have a look at the teeth on the band.

Worth mentioning Dayco is not the best. Don't know about hoses, but my bearings on the timing belt kit started throwing grease from day one, and other users mentioned the same.

WhatAmIDoing · Post by **WhatAmIDoing** » 28 Jan 2018, 12:40

Thanks for all the advice. Was hoping to avoid popping the lower hose off and draining the system. If I do that, then I might as well order a volvo lower rad hose and chuck the dayco. Lesson learned.

oragex wrote: ↑28 Jan 2018, 08:38 Which clamps are you using? Is it this type with 'protruding' teeth? See this video at 22:40 youtube.com/watch?v=3fEjbMpVSfo

The screw clamps can take so much force on them. At some point, the small teeth in the band will torn and the screw will start slipping and loose pressure. Loosen it a bit and have a look at the teeth on the band.

Worth mentioning Dayco is not the best. Don't know about hoses, but my bearings on the timing belt kit started throwing grease from day one, and other users mentioned the same.

No, that's not the kind of hose clamp in use.