Should I bother cleaning valves? If so, with what? xc70 2004

beewstew · Post by **beewstew** » 05 Oct 2024, 15:38

Took the valves out of the head of a 2004 xc70 2.5t this afternoon so I could install new valve stem seals. Lapping the valves seems easy enough - I tried with one, but I didn't keep track of them when removed so there's a 1/10 chance that each valve goes back into it's original spot. Bad idea to lap them randomly?

Should I bother cleaning the valves? Intake side seems mostly covered with a light varnish. Exhaust side has more of a carbon fur. Pictures below.

Also, what's the magic technique to get the keepers back in place? Assembly lube/Vaseline, tweezers, and a steady hand?

Intake valves
https://1drv.ms/i/c/7045d4cf7fedc911/EY ... w?e=eLh83v

Exhaust valves
https://1drv.ms/i/c/7045d4cf7fedc911/ER ... w?e=rWlbHd

All pictures https://photos.app.goo.gl/zQYJ96FpysGtMXwG8

Post by **vtl** » 06 Oct 2024, 11:28

A combination of boiling Simple Green and Muriatic acid (can of Simple Green, can of acid) did a trick for me to get rid of heavy limestone deposits. Don't soak the valve deeper then needed. You'll see a clean separation on the valve. It is made of two metal alloys in fact. The one that slides in valve guides should not be scraped, dinged or submerged in acid.

Use Permatex 81950 Ultra Slick Engine Assembly Lube to keep the keepers in place.

Make sure valve guides are absolutely, bone dry before installing new seals. Clean with acetone them good. Don't use any kind of glue. Otherwise the new seals will pop off in no matter of time. Exhaust side is Volvo original seals only. Intake you may have luck with Elring.

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Post by **vtl** » 06 Oct 2024, 11:31

Also OTC 4572 Large Valve Spring Compressor was priceless for me.

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Post by **MoVolvos** » 06 Oct 2024, 14:19

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The combination of basic products seems to clean the valves really well. I would focus on the valve seat as those valves aren't extremely dirty. Proper seating of the valves is needed for compression.
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beewstew · Post by **beewstew** » 06 Oct 2024, 20:37

@vtl I agree with you about the valve spring compressor. I bought a similar tool on amazon - indispensable!

I've had the valves sitting in sardine tins filled with SeaFoam. It took a little of the soot off, but certainly not all. Thinking about trying oven cleaner- the snowmobile forums say it's great.

Doesn't Simple Green eat Aluminum?

@MoVolvos I've got a tube of Permatex lapping compound - doing one of the valves a few days ago was fun. Would you pressure-wash afterward to make sure all the grit is out of the head? I can't imagine it'd be good for the bearings.

Post by **MoVolvos** » 06 Oct 2024, 21:08

beewstew wrote: ↑06 Oct 2024, 20:37 @vtl I agree with you about the valve spring compressor. I bought a similar tool on amazon - indispensable!

I've had the valves sitting in sardine tins filled with SeaFoam. It took a little of the soot off, but certainly not all. Thinking about trying oven cleaner- the snowmobile forums say it's great.

Doesn't Simple Green eat Aluminum?

@MoVolvos I've got a tube of Permatex lapping compound - doing one of the valves a few days ago was fun. Would you pressure-wash afterward to make sure all the grit is out of the head? I can't imagine it'd be good for the bearings.

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I think it's okay to power wash if you have a nozzle and compress air to remove moisture afterwards. Coat with lubricant as soon as you're done. You can also use a heat gun for those tight areas on low heat and air speed on fast.
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Post by **vtl** » 07 Oct 2024, 05:01

beewstew wrote: ↑06 Oct 2024, 20:37 Doesn't Simple Green eat Aluminum?

IIRC, it says "no" on a regular Simple Green jug, but in my experience it does. All my engine aluminum parts showed some heavy oxidation within a few weeks/months, even that I powerwashed everything well. It also ate a few beer cans I used for valves cleaning. Not at the rate of muriatic acid, but it still did. Could be dissimilar metals (hot tank made of zinc-plated steel welded with mild steel filler + aluminum engine parts) interacting in the presence of hot conductive solution, too.

You may have better luck with this one: https://simplegreen.com/industrial/prod ... n-cleaner/ I bought one jug, but never opened it.

Anyways, nothing went too wrong for the engine, 4 years later it still runs great.

Post by **MoVolvos** » 07 Oct 2024, 15:10

vtl wrote: ↑07 Oct 2024, 05:01
beewstew wrote: ↑06 Oct 2024, 20:37 Doesn't Simple Green eat Aluminum?
IIRC, it says "no" on a regular Simple Green jug, but in my experience it does. All my engine aluminum parts showed some heavy oxidation within a few weeks/months, even that I powerwashed everything well. It also ate a few beer cans I used for valves cleaning. Not at the rate of muriatic acid, but it still did. Could be dissimilar metals (hot tank made of zinc-plated steel welded with mild steel filler + aluminum engine parts) interacting in the presence of hot conductive solution, too.

You may have better luck with this one: https://simplegreen.com/industrial/prod ... n-cleaner/ I bought one jug, but never opened it.

Anyways, nothing went too wrong for the engine, 4 years later it still runs great.

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First thought came to mind when Simple Green was mentioned but for some reason kept thinking cast iron head however

. Simple Green was the IT degreaser but oxidized the engine compartment one time and that was it. Castrol Super Clean was the go to cleaner in 55 gallon drums when I worked at Pep Boys. Of course there is Purple Power now which is cheaper. Wonder if the purple ZEP is any good? My mechanic and Acura used a lot of their products.
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https://www.amazon.com/4320P-Industrial ... U5N4O&th=1
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https://www.amazon.com/Zep-Industrial-P ... 109&sr=8-6
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