I have Great News, I got my Brick out of the shop today and they say the clicking noise/problem is with my lifters, and is most likely not caused by uping my boost, they drained my freshly changed oil and put in 5W50 Fully Synthetic instead of 10W30 Fully Synthetic and the noise is very very quiet now. They say to drive for 200-300mi and if the noise doesnt go away by itself then they are going to open my valve cover and check things out and possibly replace lifters if that is the problem. Well I upped my boost again =), It now runs 15.5psi max sustained boost, and it has had no problems. The clicking noise is the same if not maybe a lil bit quieter. Anywayz I cant believe my ECU is allowing the boost I am putting out. Tommorow I think I am going to add a 2.5" Cat Back Exhaust System, Or should I get a 2.5"/3.0" Down Pipe First??? Also Does anyone wanna check my figures, I believe that by upping my max boost to 15.5psi, I have just by doing that alone upped my max hp by 68.558hp (15.5psi - 9.6psi = 5.9psi x 11.625hp) Giving me 290HP and 290lb/ft. Does That sound about right. Thanks for the input.

I've noticed that as I approach the time to change oil I get more
valve noise on cold starts with my 98 T5 (48K miles). Changing the
oil quiets it down til the next change. I start my car in a garage
and it is very easy to hear all the sounds it makes so it may be a
minor thing -- but I do hear it.

i had that same problem a few months ago. my (ex) mechanic told me that i needed to change the valve lifters. a 7-900$ job, parts and labor. i opted for a can of amsoil engine flush, to clean out the valves and lifters, then a used 10-30 mobil1. the noise is now a distant memory....so is the mechanic.
regards

Apparently you havent seen previous posts on subject and I think that whoever's looked at your car is not at all familiar to your Volvos engine. Why? There is NO valve cover for starters, it's an upper cam cover and it's not just easily removed to "take a peek" at the lifters in your engine.
If changing oil quieted the engine down at all (no matter what type oil is used) then I'd guess that your oil was either very dirty or gassed (too thin from gas dillution, running rich or being flooded).
The main reason why lifters make noise in "white engines" is due to low oil pressure. The main cause for low oil pressure on higher mileage or older white engines is because the oil pan (oil sump) o-rings have shrunk in time and thus you're sucking air.
If and when the lifter noise re-occurs, do NOT start with the valve train, start by having the oil pan removed and have the sump and two filter housing to pump o-rings replaced. Another area of possible pressure loss which I see with high mileage 850s is the oil pump o-ring, a large o-ring that goes around the oil pump and when it's getting bad you'll see oil leaking from the from crank seal area.
I've heard of several 850 owners who've paid good money to have cams and lifters replaced by independants only to still have the same "lifter" noise so don't be a victom of mis-diagnosis. It'll be big $$$ to replace valve train parts and a complete waste if the problem isn't solved. I have yet to ever replace cams and/or lifters in a "white engine" or ANY Volvo engine for that matter.

ED,
What is a ball park for high miles on the o-rings going on the white engines. Is it a pretty sure thing that everyone will experiance it. Any preventative maintenace ? I put my 850 on straight syn oil at 40K miles

Lee
95 108,000 K non-turbo

To R&R oil pan and replace the 3 o-rings in a '97 850, it's about 3 hours labor (book time) and parts are cheap. The newer cars with the oil cooler mounted to the pan have more o-rings.
If in doubt, have oil pressure checked with a test guage.

Mine were going bad when I bought my car @ 190,000 miles. I believe you'll first notice it when cold and it will over time tick longer and longer until it eventually does it all the time.

Installed in an afternoon of playing driveway mechanic. Cost for parts and sealer from dealer $35.

Unfortunatly no fix has worked for me and i personally feel that the previous owners drove it clacking for so long that it unfortunatly destroyed a few of the lifters. I've heard rumor of a discount price ($150?) for a set of lifters but have yet to look into it, I just keep forgetting.


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'94 855 5spd 'Drew' 202,000 Miles