I cleaned the throttle body on my '86 last Saturday. Oh, the horror of what I saw! I NEVER saw such a build up of goo. The intake manifold has layers also. Has anyone ever taken the IM off and cleaned it?
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Happy Motoring Miguel '86 244 and '87 245

After spending a few hours cleaning one in the sink( makes a nice toxic smelling brew ) I would go with Art's advice and get it bead blasted somewere. I got a new b204ft intake for a 16V turbo project and have been wondering what the best way to polish the ports would be. It seems to me that a polished surface would be much less likely to accumalate the crud then the cast alum. surface does.
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1990 240 Sdn 277K,tach,strut brace,turbo sway 1990 240 Wgn M47II 157K,tach,strut brace,poly bushings,IPD sways,bilsteins

If you plan on polishing the intake consider locating a shop that does coatings. There is a shop near my hometown that does a teflon type of coating for race engines. Rumor has it that he does some NASCAR stuff. Rumors....huh.

But if you are so inclined to have the best for your beast, coating after polishing would make the flow that much better.

For me and my normally aspirated old mare it would be money better spent elsewhere.

Good luck with the turbo project.
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Happy Motoring Miguel '86 244 and '87 245

I've been inside two, and while there was a slight coating of caked-on oily deposits, it didn't inspire shock. This must come from the PCV system via the oil separator box and flame trap.

Given the amount of crud that you see, try to get a good look down your intake ports. The port walls can't be much better than the manifold and maybe worse, as they run hotter. And the heads/stems of the intake valves?

Point is, that cleaning the manifold runners may make you feel better but is unlikely to benefit the engine much, with ports and valves carrying deposits.

Volvo are aware of this and at one time our local dealer offered a cleaning treatment in which they pulled the manifold away from the head and, using crushed walnut shells as the abrasive, blasted the intake ports and valves (presumably one at a time, on closed valves!). They identified the deposits as a cause of rough idle and poor low speed running. I didn't like the sound of this process, so declined to try it.

I've seen the wall posters in those tire/brake/tune-up shops showing a crudded-up valve 'before' and a sparkling clean one 'after' their fuel injection cleaning treatment; I truly doubt those magic processes do any tangible good. But willing to be corrected on that if anyone has real-world results to report.
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Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, 'my' 94-944 B230FD; plus grocery-getter Dodge minivan, hobbycar MGB, and numerous old motorcycles)

The shock I had expressed was due to never having seen such crud before in my automotive experiences. I have torn apart engines before and NEVER seen such crud. Obviously Volvos are extremely tough engines. And Yes it is due to the recirculation of the crankcase gases. I am amazed that the car runs as well as it does, I mean there is a lot of crap going into the engine.

I don't think I'll take it out after all. The car must have 220,000+ (the odometer stopped running 4 or five years ago)and still runs .....
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Happy Motoring Miguel '86 244 and '87 245

Yeah mine is like that, too. My car needs injectors, so I may try and clean it when I take them out. Wonder what the best way to clean the intake would be? I was thinking about using a can of carb cleaner and a toothbrush.

Cheers,
Dave

I was thinking more on the lines of removal and parts cleaner for a week!
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Happy Motoring Miguel '86 244 and '87 245

Took one over to the machine shop next to WAP for hot tank and bead blast. $30 worth of vanity.