Hello-

I am replacing the original RMS on my non-turbo 850 at 160,000 miles. At the same time I am addressing any positive crankcase pressure that may be contributory. The independent shop who is doing the work insists that the flame trap must be in pace (they even said by law). Now I know this is a stretch. I read somewhere that there may have been a service bulletin on this, but my understanding is that on the 850s flame traps are not necessary to prevent engine fires and that they do more harm than good. Bay13 says that 1998s (presumably s70s) left the factories w/o flame traps. Does anyone here have a sense of official word on this for 850s? Being California, most shops I've talked to are pretty dogmatic about keeping with original EMS specs. Since I am sinking the big bucks into the RMS repair I don't want a headache 20K down the road.

Thanks,
Paul

Remove it. It's an appendix.
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'97 855na, Mobil 1, K&N, various IPD's and eBay's

thanks! just so i can put the argument to rest, what's the doc it's appended to? or do you mean this metaphorically, as in the unnecessary organ?

thanks,
paul

Thanks guys. The independent shop (only Volvo one in my area) insists on putting the flame trap back in after replacing the rms and working on the pcv system. It could be an example of a California fear-of-liability thing, but it's annoying because I'll have to go in and remove the flame trap asap. Some mechanics, much like doctors, seem to strongly dislike input from their clients. But since this shop is charging $750 for the rms job instead of $1K+ at the dealer, I can put up w/ a little nonsense I suppose.

Unnecessary organ that can cause severe acute pain and trauma to your wallet if it comes encrusted with burnt oil crud and causes a rear main seal leak. I don't know if Volvo has given its blessing officially, but I struggled with the same question and even left mine in for a while after hearing from this forum to take it out. I went through 2 main seal replacements. The first one the shop only did the seal and not the other PCV components (sigh)
It's designed to prevent an engine fire in the event of a cylinder backfire. 1) I don't know if anyone here has ever had any backfire at all (I know I haven't) 2) the backfire would have to travel through a very skinny and long hose to reach anything (correct me if I'm wrong)-it's just very very unlikely 3)what is common is rear main seal leaks, if you kept it in, you'd have to check it, and replace it very frequently.
All this said I am not a mechanic or a Volvo representative, I just have been reading this board for 8 years and am pretty confident that everyone throws them out, and it's not dangerous to do so. Post back with any other questions -no prob. Maybe some others will weigh in. You can also call FPC Groton, IPD, or your Dealership parts Dept.
Thanks
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'97 855na, Mobil 1, K&N, various IPD's and eBay's

It is an unnecessary organ. The flame trap "screen" is to be taken out and disposed of properly. It serves no function except to clog up and cause needless repairs.

What might be in more need of replacement is the oil seperator box under the intake manifold. When that gets clogged up, you will blow seals like crazy, and that usually happens after 120K miles.
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My name is Klaus and I am a Volvoholic.