$6500 for repairs?

[precopster]

Perhaps that shop fitted some NGK Iridium spark plugs which it seems have a hit and miss success rate according to recent posts: viewtopic.php?f=5&t=54863

Can you pull one of them to see? Would be interesting to see if they were properly gapped while you're in there. Too much anti-seize used causing arching and bad flame path? Some of the most basic maintenance items can be done poorly if they're in a hurry. Even an untorqued spark plug can cause major havoc.

Were Genuine coil packs used or at least Delphi which is OEM?

[RickHaleParker]

Considering what that shop cost, I got to ask: Do they serve the customer Gray Poupon?

[June]

Considering what that shop cost, I got to ask: Do they serve the customer Gray Poupon?

I agree! The OP is paying dealership price without getting the Volvo lifetime warranty on repairs! So I would reconsider using a indy that cost that much, or use the dealer and have the lifetime parts and labor warranty as well as guaranteed genuine Volvo parts being used. If you're going to spend that kind of money on repairs, why not get the guarantee! June

[pgill]

Andy,

The 3.2 Liter 6 cylinder engine in your XC90 is a very dependable engine.

I like the design enough that i purchased two vehicles with the same engine (and I still own both vehicles)

I've owned my first 3.2 since 2008 (11 years)

During that time I've researched the typical things that go wrong and I've been proactively replacing based on the experience of others.

My recommendation is to replace the Thermostat.

This is a known failure point for the 3.2 and you are at the right mileage for the failure to occur.

And there is some evidence that the broken Thermostat can cause coil failure.

I have lots of links that I can share but I see that this is your third post and I don't want to overwhelm you with information.


The good news is that based on what I've read the XC90 has sufficient room in the engine bay that the Thermostat can be replaced without removing the intake manifold (This is not the case for the 3.2's that I own)

if you do have the Thermostat replaced then let us know if that clears the P0420 code.

If not I have additional suggestions for the P0420

Good luck

Paul

[AndyG]

Check engine light is back on and the same code (P0420 catalyst efficiency trouble) is coming up. I took it to a local shop and the mechanic says the new plugs/coils could be causing the catalyst to misinterpret the boosted power from new items, making the CEL come on. He suggested simply using a bottle of CataClean to see if that helps. Thoughts?

[AndyG]

Just saw your message, Paul. I can try that too.

[pgill]

Picture of the broken Thermostat on my 2010 S80

http://www.freel2.com/forum/topic33004.html

Note: this is from the Land Rover forum (the LR2 uses the Volvo 3.2)

Have fun

Paul

[precopster]

Without pulling coils/plugs to see what they fitted (regular plugs or something fancy) and how they fitted them it's just a guessing game, though if this fails to find the problem it's still a guessing game.

The thermostat failure can affect the mixtures and make car run rich when cold; hence the codes. Blowing coil packs as a result is extremely unlikely.

Personally I would buy my own set of plugs/coilpacks and a thermostat and start over.

[pgill]

Andy,

I posted this on another board but I thought you would give you some hope that there is light at the end of the tunnel (and I'm not talking about a train)



Copied from a post on Freel2

My neighbor drives a Toyota Pickup

His truck is >100,000 miles and a 2006 model year

Check engine light is on

P0420 Catalyst not operating properly

Full disclosure: He knows nothing about cars

I search the Evil Toyota Empire boards - nothing useful

Based on what Volvo did for the 3.2 and 3.0T I decided to try Denso Iridium TT plugs in his Toyota

I reset the MIL and he drove his truck for a week.

No more MIL and he passed the state required emissions check.

Maybe I should join the Toyota boards and let them know what I did.

No chance of that happening..............

If they wanted my help they should have bought something interesting like a Land Rover or a Volvo.


Let us know what you find out

Thanks

Paul

[RickHaleParker]

He suggested simply using a bottle of CataClean to see if that helps. Thoughts?

It can't hurt and it is possible there is crud from the misfiring causing the P0420.

If you do this, read the instructions on the bottle, do the math and get the mix ratio correct. I suggest taking it out on the Interstate for a long drive, say 150 miles. That way your get a steady flow of the cleaner, not the all over the map flow you get with stop and go driving.