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97 850 dash/headlights flickering only at startup. UPDATED

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

Peevarino
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Year and Model: 2009 XC70, 97 855R
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Peevarino

Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by Peevarino » Sat Jan 18, 2020 4:54 pm

UPDATE!

It’s been doing the flickering a bit more often, but still only at idle, looked over a few other things, the battery to starter wire isn’t as bad as I thought once I removed a bit of the heat shrink.

Wondering if the PO had routed the serp belt the old way (less contact on alt pulley), I had a closer look. It’s routed the updated way, but when I checked tension, I realized it didn’t really have any, except I guess under load. I could move the tensioner pulley fore and aft a bit more than is probably acceptable.

So, I’ll be putting a new tensioner and belt (might as well, right?) as soon as time and shipping allows, assuming there aren’t two perfect examples at the pullapart tomorrow.

Will it solve the flickering? I hope so, but it seems like the car needs it anyway.
09 XC70 3.2
97 855R

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misha
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Year and Model: '97 850 2.5 20v
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Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by misha » Sat Jan 18, 2020 6:01 pm

It could be that voltage regulator brushes are worn out.
Diodes should be checked too and alternator tested by a specialized shop.
About serpentine belt tensioner....you shouldn't be able to move it by hand.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

Peevarino
Posts: 64
Joined: Tue Aug 30, 2016 7:18 pm
Year and Model: 2009 XC70, 97 855R
Location: Louisiana
Has thanked: 26 times
Been thanked: 3 times
United States of America
Peevarino

Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by Peevarino » Sat Jan 18, 2020 6:22 pm

I’ll be pulling a couple voltage regulators out tomorrow, as well, I seem to recall a couple newer looking alternators in the few P80 cars at the yard.
09 XC70 3.2
97 855R

User avatar
misha
Posts: 4144
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 49 times
Been thanked: 112 times
Serbia
misha

Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by misha » Sun Jan 19, 2020 3:53 am

The easiest thing is to try with replacement tensioner.
If that doesn't cure it....than attack the alternator.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

Peevarino
Posts: 64
Joined: Tue Aug 30, 2016 7:18 pm
Year and Model: 2009 XC70, 97 855R
Location: Louisiana
Has thanked: 26 times
Been thanked: 3 times
United States of America
Peevarino

Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by Peevarino » Sun Jan 19, 2020 7:19 am

That’s the plan, tensioner needs replacing anyway. If the alternators’ brushes look good at the junkyard, I’m going to get them, cheap backups just in case.

I really wish I had gone to the junkyard yesterday, though, it’s almost 30 degrees colder today.
09 XC70 3.2
97 855R

Peevarino
Posts: 64
Joined: Tue Aug 30, 2016 7:18 pm
Year and Model: 2009 XC70, 97 855R
Location: Louisiana
Has thanked: 26 times
Been thanked: 3 times
United States of America
Peevarino

Re: 97 850 dash/headlights flickering only at startup. UPDATED

Post by Peevarino » Sun Jan 19, 2020 3:18 pm

Found a properly working tensioner and pulley at the junkyard, along with a nearly new Volvo stickered Bosch alternator. The PO put in a O’Reilly reman alt at some point, so I figured get it when I can.

No time left to put tensioner in today, family time and grocery run take priority now.

I’ll report back once the tensioner is in, I may have time on my lunch break tomorrow, assuming it’s not raining.
09 XC70 3.2
97 855R

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