Wooosshhh!!!! sound accellerating TURBO

Cees Klumper · Post by **Cees Klumper** » 13 Jul 2025, 09:37

Today, after replacing the brake master cylinder en front brake discs on my 2001 C70 T5 and (of course) bleeding the brake system I went for a test run to check the work and bed in the discs. Everything was A-ok however, close to home as I was returning, which is up a steep hill, I decided to give it the beans and there was an unbelievably loud WOOOOSSHHH noise coming from under the car! First I thought I was maybe imagiing things as I was in between dense shrubs and trees and was driving with the top down, but a bit later in the open it was still there and still as loud.
I decided to first take a look under the hood, to see if maybe a turbo hose had popped loose since that's what it sounded like to my untrained ear. Nothing ontoward visible.
Then took out the OBD2 scanner but no codes in the engine management side of things.
So, ventured underneath the car and after removing the front lower panel, saw the smoking gun: a hose clamp that was still hanging on for dear life, but snapped in two. The supply hose to the intercooler was only 'sort of' connected.
Popped on a new clamp, went for a test drive and problem solved. During the drive looked at live data for boost pressure and turbo control valve duty cycle % and both looked healthy - and the car accellerated and sounded completely normal.
Maybe soon I should have a good look around what else may be on the way out...

Post by **scot850** » 13 Jul 2025, 16:47

That is the sort of crusty pipe clamp I would expect to see on the East Coast or up here. Wow!

Neil.

melmaclifeform · Post by **melmaclifeform** » 13 Jul 2025, 18:33

I thought things weren't supposed to get rusty in California?

Cees Klumper · Post by **Cees Klumper** » 13 Jul 2025, 22:37

Haha I was surprised as well at the state of it.

Things can get rusty in California as well, however this car sits with its 2002 cousin the S80 T6 at our summer home in France. Before France we lived in The Netherlands and Switzerland, also countries that use salt on the roads in winter, so that likely explains it. Still I would have expected this clamp to have been the stainless steel variety.

Post by **abscate** » 14 Jul 2025, 03:19

Most of the stainless steel clamps are very low grade stainless, with predictable results. The ABA or stock Norma Volvo clamps cost more money but are much better quality and won’t rust. If you save Francs here, you need to up the inspection time investment accordingly. Einstein taught us that space, time, and money are all intertwined in the Theory of how much Money you leave your Relatives

Post by **FireFox31** » 17 Jul 2025, 00:16

Thanks for sharing the warning. I can't tell if that's an original clamp because of the focus. Looks like it has the rolled edges but the sliding end doesn't look right. I buy stainless Norma Torro and ABA clamps from BelMetric for less than the identical Volvo parts. I wrote a thread about clamps somewhere here, listing how you can identify the various levels of stainless quality (band only, band and screw, etc).

My first V70 engine was destroyed when a hose blew off and dumped all the coolant (and I panicked and drove instead of stopping). Ever since, I invest in the best quality clamps... for my busted $500 cars.

Cees Klumper · Post by **Cees Klumper** » 17 Jul 2025, 22:58

I think it's the original clamp because I've owned the car since it was 3 years old with only 20K miles and no work has ever been done on the turbo system. Moreover, I inspected the various adjacent coolant hose clamps today and they exhibit similar corrosion, so I will be replacing all of these ASAP. Those have never been touched either. In fact, I better order me a complete set of new coolant hoses as well ...
This C70 has been one of the most reliable, trouble free cars I've ever owned. Over the past 20 years and 230K kms (besides normal wear items) it's only had to have its trans control module, the two rear springs and the VVT solenoid replaced. I replaced the heater core out of precaution.