[bradysasha]

Hello,

I am about to buy an 05 XC90 V8 with 111k miles. seems to be in very nice condition. I know the dealer just replaced a wheel bearing. Am I making a mistake? I have read all about the engines blowing due to the bearing. What should I be looking for or should I steer away?

This will be my first Volvo.

Thank you so much in advance for your input!

 

[cedarholm]

The most important thing is the engine number.

Call the dealer and get the engine number and ask if CB bearing has been changed.

Two good threads here on CB bearing failures.

Looks like engine # 6833 and up is OK.

 

[cedarholm]

Hello,

I am about to buy an 05 XC90 V8 with 111k miles. seems to be in very nice condition. I know the dealer just replaced a wheel bearing. Am I making a mistake? I have read all about the engines blowing due to the bearing. What should I be looking for or should I steer away?

This will be my first Volvo.

Thank you so much in advance for your input!

2005 or 2006????

 

[SullyE]

Greetings.

You mentioned the dealer replacing a wheel bearing, but you also asked about the engine counter-balance shaft bearing. Could you please clarify for us?

I just bought an 06' XC90 AWD V8 about a month ago... and had to deal with a failing valve body in the transmission. What a headache. From what I read during research, the counter-balance bearing issue was only with the 05's. The issue was resolved for the 06's, again, from what I understand. Maybe others can confirm that and provide further details if needed.

Thanks.

 

[XC90Dirk]

As I understand it, the "issue" is with the way the V8 has its counter-balance shaft mounted. This applies to all model years as the design hasn't changed. The 2005 model year, up to engine 6833, did not drain the valley in which the shaft is mounted and permitted any standing water there (from engine bay washing, etc.) to make contact with the bearing and begin oxidizing, which would spread into the bearing ultimately destroying it. The "fix" was to drill a drain hole which happened before the end of the 2005 model year run, so vehicles built late in the 2005 run will have the remediation, which is why you've been warned to check the engine number. I'm not aware that any upgrade or redesign of the bearing ever happened. Vehicles which suffered a bearing failure and were repaired by Volvo dealers, should have had the hole drilled making them functionally equivalent to a late-2005+ car. Anecdotal evidence suggests that these "drilled" engines are immune to the problem now, but since the damage comes as a result of oxidation there's no guarantee that it's not still happening, but at a much slower rate.

Full-disclosure: I have an early 2005 model with 106,000 miles and no signs of bearing problems, and no dealer records of any CB bearing repair or remediation in the past. (I bought used, before hearing about the issue)

 

[gascos80]

As I understand it, the "issue" is with the way the V8 has its counter-balance shaft mounted. This applies to all model years as the design hasn't changed. The 2005 model year, up to engine 6833, did not drain the valley in which the shaft is mounted and permitted any standing water there (from engine bay washing, etc.) to make contact with the bearing and begin oxidizing, which would spread into the bearing ultimately destroying it. The "fix" was to drill a drain hole which happened before the end of the 2005 model year run, so vehicles built late in the 2005 run will have the remediation, which is why you've been warned to check the engine number. I'm not aware that any upgrade or redesign of the bearing ever happened. Vehicles which suffered a bearing failure and were repaired by Volvo dealers, should have had the hole drilled making them functionally equivalent to a late-2005+ car. Anecdotal evidence suggests that these "drilled" engines are immune to the problem now, but since the damage comes as a result of oxidation there's no guarantee that it's not still happening, but at a much slower rate.

Full-disclosure: I have an early 2005 model with 106,000 miles and no signs of bearing problems, and no dealer records of any CB bearing repair or remediation in the past. (I bought used, before hearing about the issue)

Correct to a degree...from the pictures of damaged bearings provided by the forum participants it is apparent that the damage is a plain water induced rust, not just the oxidation. Thus absence of water around the bearing seems to be sufficient to turn statistically significant problem into piratically non-existent...

Pre-lubricated bearings are very common. I hope that Volvo was sufficiently diligent in determining the extend of remedial measures...

For the record - my wife drives early 05 V8 with 105K on a clock with no signs of the problem...

 

[XC90Dirk]

Ah, right. I think I remember one of those pictures. It showed a very rusty counterbalance shaft leading to the bearing caked with junk. I'm hoping that my nearly-always garaged XC and 20+ minute commute (and lack of interest in washing the engine) is keeping that area dry enough to prevent the problem.

 

[pengc99]

...the damage is a plain water induced rust, not just the oxidation...

Rust is oxidation

Sorry, engineer in me decided to rant.

 

[gascos80]

Rust is oxidation

Sorry, engineer in me decided to rant.

Rust is not an oxidation (in a colloquial usage of terms) ...sorry, materials scientist in me decided to rant..the presence of sufficient amount of water is essential to what is commonly called process of rusting...mositure control is one of the major passive rust-prevention measures...

Even chemically, the rust as the result of moist air/water exposure and dry air exposure are different. The former are hydroxides, that do not adhere to the metal surface and do not stop further exposure. The latter - mostly oxides that typically create a sturdy film on a surface of metal that significantly slows or completely stops further exposure...

Those are the scientific reasons why simple reduction of exposure to water can drastically improve the life span of a bearing...

 

[glenwyatt]

Rust is not an oxidation (in a colloquial usage of terms) ...sorry, materials scientist in me decided to rant..the presence of sufficient amount of water is essential to what is commonly called process of rusting...mositure control is one of the major passive rust-prevention measures...

Even chemically, the rust as the result of moist air/water exposure and dry air exposure are different. The former are hydroxides, that do not adhere to the metal surface and do not stop further exposure. The latter - mostly oxides that typically create a sturdy film on a surface of metal that significantly slows or completely stops further exposure...

Those are the scientific reasons why simple reduction of exposure to water can drastically improve the life span of a bearing...

It's like being in school all over again...LOL

 

[Excimer]

"Rust is not an oxidation (in a colloquial usage of terms)"

I am having a hard time with this. Rust is oxidation and is the result of the combination of iron with oxygen, regardless of source.
Is water necessary for rust to form? No. Only oxygen must be present. The process of rusting is the reaction of iron metal (Fe) combining with oxygen gas (O2) to form iron oxide (FeO or Fe2O3). Water (and salt) speed up this reaction a great deal, but oxygen is the only one that is necessary.

What am I missing.

 

[gascos80]

"Rust is not an oxidation (in a colloquial usage of terms)"

I am having a hard time with this. Rust is oxidation and is the result of the combination of iron with oxygen, regardless of source.
Is water necessary for rust to form? No. Only oxygen must be present. The process of rusting is the reaction of iron metal (Fe) combining with oxygen gas (O2) to form iron oxide (FeO or Fe2O3). Water (and salt) speed up this reaction a great deal, but oxygen is the only one that is necessary.

What am I missing.

Sorry, you are missing the actual knowledge of a process...you oversimplify the reactions, and the result is NOT necessary the oxides, but likely the hydroxides (

"In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture. "

"Oxidation of iron metal
When impure(cast) iron is in contact with water, oxygen, or other strong oxidants and/or acids, it rusts. If salt is present as, for example, in salt water, it tends to rust more quickly, as a result of the electro-chemical reactions. Iron metal is relatively unaffected by pure water or by dry oxygen. As with other metals, like aluminium, a tightly adhering oxide coating, a passivation layer, protects the bulk iron from further oxidation. Thus, the conversion of the passivating iron oxide layer to rust results from the combined action of two agents, usually oxygen and water. Other degrading solutions are sulfur dioxide in water and carbon dioxide in water. Under these corrosive conditions, iron hydroxide species are formed. Unlike iron oxides, the hydroxides do not adhere to the bulk metal. As they form and flake off from the surface, fresh iron is exposed, and the corrosion process continues until either all of the iron is consumed or all of the oxygen, water, carbon dioxide, or sulfur dioxide in the system are removed or consumed.[2]"

you can start here..

http://en.wikipedia.org/wiki/Rust

the wikipedia is great for the purpose of quick educational reading...

Cheers,

P.S. Look, MS in Metallurgy and MS in Materials Science give me somewhat decent understanding of what the complex process that commonly called "rust" is...My English maybe rusty though...

 

[gascos80]

Apologies for digressing...

...but how about the oxidizing as the rust prevention finishing?

http://www.swdinc.com/black_oxide.htm