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V70R T5 bent con rod. Cause?

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Old May 6th, 2019, 19:11   #1
dave88sw
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Default V70R T5 bent con rod. Cause?

Hi,

Last week i was driving to work, put my foot down on a hill, felt a big misfire followed by a sound like a machine gun. Scratched my head for ages, googled a bit and found these engines are known for bending rods if the turbo over boosts. Well, i've stripped the engine (what a job!!) and sure enough, bent number 2. I've been fairly lucky in as much as nothing else is damaged so it is repairable.

My question though, is what caused it? Most theories seem to suggest a vacuum leak between the boost control solenoid and the wastegate but i have previously replaced all these vacuum hoses and they're still in good shape. If i suck on the pipes to the turbo i can't pull any air through them so i assume the pipes and diaphragms are in good order. Is it possible it's the boost control solenoid itself? Is there anything else i should check?

Also, has anybody had any good/bad experiences with these con rods?
https://www.ebay.co.uk/itm/4340-TuV-...cAAOSwIVVcky-3

Or can anyone suggest an alternative that isn't going to cost the earth?

Many thanks
Dave
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Old May 6th, 2019, 21:33   #2
DSK
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Tcv / boost solenoids may appear ok but with age/wear etc they can cause the turbo to over boost the wrong way causing the very issue you describe. It’s why changing the TCV frequently such as every couple of years, is strongly advised.
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Old May 6th, 2019, 22:27   #3
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Quote:
Originally Posted by DSK View Post
Tcv / boost solenoids may appear ok but with age/wear etc they can cause the turbo to over boost the wrong way causing the very issue you describe. It’s why changing the TCV frequently such as every couple of years, is strongly advised.
Interesting - where do you recommend getting them from? Is Volvo the only source? Or are aftermarket or DIY options viable?
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Old May 6th, 2019, 23:05   #4
DSK
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FRF volvo - we get a forum discount.

I do about about 800 miles a week and change mine annually for peace of mind.

There are other options such as over hyped performance items such as IPD but it’s just hype and over priced to con those who don’t know better.
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Old May 7th, 2019, 22:33   #5
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That's very interesting, I sort of assumed it would either work or not. In that case i will replace it regardless as i know it hasn't had one in many years. I will give everything a thorough checking over before i put it all back together too. It's in incredibly good condition inside considering its done about 170,000 miles.

Thanks
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Old May 8th, 2019, 18:51   #6
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I left mine a little longer than the usual annual (30,000 miles for me) as it just slipped my mind.

The car still felt ace and smooth but, after replacement, its MUCH more torquey and responsive.
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Old Jun 2nd, 2019, 09:00   #7
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Quote:
Originally Posted by dave88sw View Post
That's very interesting, I sort of assumed it would either work or not. In that case i will replace it regardless as i know it hasn't had one in many years. I will give everything a thorough checking over before i put it all back together too. It's in incredibly good condition inside considering its done about 170,000 miles.

Thanks
Dave
I had a bent conrod on an 850r are had no idea how it happened could not find anything causing it and I only had an 16t.

Have fitted the same conrods you are looking at and I've never looked back just make sure you check your clearances on the replacement bearings you're using.

https://youtu.be/p-zSPtrK7bw

This is a video of the noise of mine before and after
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