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08 xc90 3.2: how do I remove exhaust manifold shield?

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
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ogatrulle
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ogatrulle

08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ogatrulle » Tue May 28, 2019 1:50 pm

2008 xc90 3.2 135k mi

I am chasing a P0420 and suspect a small exhaust leak. I need to get the exhaust manifold heat shield off in order to get a stethoscope in there.

There are three M8 bolts along the top of the shield and two more on at the rear of the shield. I think I can get the two rears, but the three along the top are positioned almost directly behind a coolant pipe.

It wouldn't be so bad if I could just unbolt the two coolant pipe brackets along the back of the engine, but on the left side of the engine, the pipe seems to be rigidly connected/welded to some sort of flange that is bolted to the rear of the engine. I'd rather not open up the cooling system just to get the heat shield off.

The space is too narrow for me to get my ratchet+socket onto the upper heat shield bolts. I can get a 10mm box wrench onto the bolts, but there is no way to turn it because the shield sticks out.

Has anyone gotten the heat shield off on the 3.2? How did you do it?

thanks!


2006 v70 2.5T; 2008 xc90 3.2

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pgill
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Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by pgill » Wed May 29, 2019 11:57 am

I own two P3 vehicles both with the 3.2 (note the XC90 is actually a P2)

But I've never had to remove the heat shield for the exhaust.

The 8 mm that you are referring to is the size of the Hex not the size of the bolt diameter?

If yes then have you considered a Ratcheting Box wrench?

Like this https://www.amazon.com/TIGHTSPOT-Moveme ... =8-4-spell


You did not ask for my advise but I will give it just in case you are interested

I've never had P0420 for either of my 3.2's

But my neighbor had a P0420 on his Toyota until I fixed it for him

Here is what I would do if I did get the P0420 code on a 3.2

1. confirm that the outside air temperature sensor is working (is the outside temperature on the instrument cluster correct?)

2. remove and replace the Thermostat (the thermostat fails around 10 years and 100K miles)

3. remove and replace the spark plugs (upgrade to the Denso TT plugs - Denso (4704) IKH20TT you need 6)

- Note: the wire connecting coil #1 and #2 can be swapped if you are not careful

4. check the coils if any of them are discolored or smell burned replace any suspicious coils


I am not sure if you are aware that the Land Rover LR2 is a P3 chassis with the same 3.2 as the Volvo S80.

There are some minor differences between the 3.2 in the P2 chassis and the 3.2 in the P3 but those differences are not relevant to what is posted above

Here is the procedure for replacing the Thermostat on the my Land Rover LR2

Note: for the XC90 several people have indicated that the Thermostat can be removed without removing the intake manifold

For my LR2 and S80 I had to remove the manifold

http://www.freel2.com/forum/topic32245.html

Note: all of the parts listed will bolt right up to your Volvo (except LR019341 that part is P3 only the P2's use a different part)

In fact that is exactly what I did for my 2010 S80 I bought the Land Rover Thermostat and installed it on my Volvo.

Its the same part only it comes in a Land Rover box and its half the price of the Volvo part.

Good Luck

Paul



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Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ggleavitt » Wed May 29, 2019 5:24 pm

See https://eet-engines.com/en/volvo/s80/mo ... 6324s.html for a couple decent photos plus the below diagram
GR375071_Shield.JPG
GR375071_Shield.JPG (43.39 KiB) Viewed 277 times
VIDA repair notes this part coming off with the engine in the car. The three upper bolts that attach to the block are M8x16mm (PN 982793), there are two more bolts (different size PN 958180) that need to come off at the rear of the shield (attached to the upper cats).

edit 052919-add diagram


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Masscomguru
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Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by Masscomguru » Thu May 30, 2019 1:19 pm

I would be more suspect to the flex pipe leaking than the manifold gasket... There have been more of these codes due to that and the thermostat as pgill states above.



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ogatrulle
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ogatrulle

Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ogatrulle » Fri May 31, 2019 9:46 am

Thanks to all for lots of good info above.

Yep, tried a ratcheting box wrench. Problem is that I can't turn it past horizontal because the handle intersects with the heat shield below or the engine above. However, I did see a flex-handle box wrench for sale on AMZ so might try that.

Thanks for info on the thermostat/plugs/coils. I may yet go that route if I the exhaust diagnosis doesn't pan out. I read that the overheating from a failed thermostat on this engine might be sufficient to cause misfires without an obvious needle shift of the coolant temp gauge, but maybe I can monitor coolant temp with VIDA and check thermostat that way. Note that I have only intermittent P0420 and no other codes.

I did not think of the flex pipe, but it is probably the top candidate for me to check next. I suspected exhaust because I think I can hear a small leak, but I have not identified the location. I seem to recall I can get at the flex pipes from underneath without removing the heat shield, so will investigate there next. Spouse is driving this car so I have not had a chance yet to spend more "quality time" with it since I first posted above.


2006 v70 2.5T; 2008 xc90 3.2

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Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by pgill » Fri May 31, 2019 10:10 am

Thanks for the update

Let us know what ultimately fixes the problem.

The 3.2 doesn't have the loyal following of the earlier 4 cylinder an 5 cylinder Volvo's.

But I do believe with a little preventative maintenance that it is a 300K+ motor. (I've been advising a friend for maintenance on his 3.2 and he has >200K)

For example: Thermostat, spark-plugs, synthetic motor oil, change all fluids regularly, and the freewheel pulleys (there are two)

And I like mine enough that i bought two.
2008 LR2 3.2
2010 S80 3.2

Don't forget to check the outside air temperature sensor (does the dash display the correct outside temperature).

The ECU uses that sensor to determine how quickly things should warm up and the Catalytic converter only works when it gets hot. If the sensor is bad then the ECU may set a code like P0420

Good Luck

And remember Denso Iridium Plugs are the best choice (you can buy them from directly from Volvo if you prefer)

Paul

P.S. as for the "In flagrante delicto" we will keep it quiet and not tell your wife



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ogatrulle
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ogatrulle

Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ogatrulle » Sun Jun 02, 2019 10:16 pm

I got under the car today with stethoscope, but did not detect any exhaust leaking around the flex area.

However: there was a low buzz coming from the pinhole of the oil trap (where the membrane is). Goes away when I remove the oil filler cap. I don't know how to post my video of the location/sound. Not very loud like I have heard on various videos, but I see a new membrane/oil trap in my future.

Looks like I have several options:
  • buy membrane only ($20-$40) and pray I don't break the cover while replacing
  • buy aftermarket trap assembly ($40-$50), with possibly misaligned holes
  • buy Volvo 30788481
  • buy LR023777
I have not seen a writeup for removing the circular cover over the membrane. All the videos I've seen show broken plastic when the round cover is removed.


2006 v70 2.5T; 2008 xc90 3.2

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Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by pgill » Mon Jun 03, 2019 9:28 am

To remove the plastic cap that covers the membrane you will need a heat gun and a lot of patience

A friend from Australia was successful in replacing his.

I assume that he used a heat gun.

http://www.freel2.com/forum/topic31456.html

Take care

Paul



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ogatrulle
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ogatrulle

Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ogatrulle » Sat Jun 15, 2019 5:16 pm

I got a new LR023777 and installed it, and then I cleared the diagnostic codes. After a week of driving, P0420 is back.

Apparently I was not patient enough because I did not get the round cap off of the old oil trap without breaking a little of the plastic uder one of the tab slots. However, I found that the membrane was intact. So a buzzing sound from the pinhole in the round cap might be normal; in any case, it was not a loud whistle as others described when they had failed membranes. I don't hear any sound from the new oil trap.

So I'm back to square one. I still think I hear a faint exhaust leak sound, so I'm going to have to listen around the upper exhaust with the stethoscope.


2006 v70 2.5T; 2008 xc90 3.2

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ogatrulle
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ogatrulle

Re: 08 xc90 3.2: how do I remove exhaust manifold shield?

Post by ogatrulle » Sun Jul 14, 2019 10:12 am

Update (although no definitive fix yet):

1. With a flex 10mm ratcheting box wrench (TEKTON WRN57110) I was able to get the three upper exhaust heat shield bolts (along the back of the engine) off. The two lower/rear bolts came off with an 8mm box wrench, reached while I was underneath. None of these bolts was easy to get at.

2. Despite getting the heat shield bolts off, there did not seem to be room to actually extract the shield. But it was enough to get some limited access to the exhaust manifold area.

3. I tried two methods for leak detection. First I pressurized the exhaust (made an adapter from plastic water bottle to the exhaust outlet) with air and sprayed soapy water. I did not see bubbles anywhere between the engine and the rear O2 sensors. I am not sure of the structure of the flex pipe section, so it's possible any bubbles were obscured by the braid. Second, I hooked up my smoke generator to the exhaust outlet and let it run for about ten minutes. No smell or visible smoke at the front of the exhaust. But if it's a small leak, I'm not convinced the smoke would have made it all the way up the exhaust pipe in that time. I have no experience smoke testing the exhaust so not sure what to expect.

4. I did install six new Denso 4704 plugs. I set the gaps to .044. Coils looked OK, but five of them were probably original (135k mi). I had to replace one of them a few years ago and ordered a spare along with the plugs which was good because...

5. After another few hundred miles of driving, the engine became rough and threw P0303 and P0305 codes. Having only the one coil on hand, I replaced #3 and cleared codes. It ran smoothly and P0305 did not reappear. Maybe there is some imprecision in the way misfires are detected and cylinder 5 was wrongly flagged. In any case, I also replaced the remaining four original coils. Only a few hundred miles of city driving so it's too soon to tell if P0420 will reappear.

6. I have not yet taken the plunge to replace the thermostat. For what it's worth, the dash temp gauge still reads a hair under the center tick mark, although I have read that thermostat failure in these cars will not necessarily produce a visible effect at the gauge. I am thinking of connecting my laptop with VIDA to see if I can log coolant temp as it warms up and get some idea of actual thermostat opening point.


2006 v70 2.5T; 2008 xc90 3.2

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