How To Replace The Head Gasket On A Volvo 850 (page 3)


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Exhaust Components, Starter, Serpentine Belt Removal




DISASSEMBLY - Remove the ground leads from the top section of the cylinder head at rear near firewall (10mm). Mine had 2 of these.
REASSEMBLY - Replace the ground leads on the top section of the cylinder head at rear near firewall.






DISASSEMBLY - Remove the exhaust heat shield from the exhaust manifold on the firewall side of the cylinder head (12 or 13mm). There are five bolts total (yellow dot indicating one not shown in picture), 2 on the lower side and 3 on the upper side nearest the engine. This requires a little manipulation to remove it (removes from top side).
REASSEMBLY - Replace the exhaust heat shield on the exhaust manifold on the firewall side of the cylinder head and torque to 11 ft/lb. There are five bolts total (yellow dot indicating one not shown in picture), 2 on the lower side and 3 on the upper side nearest the engine.






DISASSEMBLY - Remove the exhaust manifold nuts (12 or 13mm); the threaded studs should stay in the head. There are ten of these, two for each exhaust port, located diagonally at opposite corners of each exhaust port. Mine came off easily, but many times exhaust components can be heavily corroded. If they look corroded at all, spray them down with a good penetrant like PB Blaster - let sit - and repeat (sometimes for a few days) before attempting to remove them.
REASSEMBLY - Flex the exhaust manifold back as much as possible, tilt it, and position it onto the threaded studs on the head (that should already have the gaskets on them). Torque the nuts to 18 ft/lb.






DISASSEMBLY - Remove the 4 nuts (13mm) where the exhaust manifold meets the exhaust pipe at the flange (best done from underneath the car). Mine came off easily, but many times exhaust components can be heavily corroded. If they look corroded at all, spray them down with a good penetrant like PB Blaster - let sit - and repeat (sometimes for a few days) before attempting to remove them. Remove the exhaust manifold from the engine well. This requires a little manipulation to remove it (removes from the top side).
REASSEMBLY - Apply the new flange joint gasket (FCP Groton Part #9135122) to the exhaust manifold at the flange end, using the four threaded studs to hold it in place. Install it back onto the front exhaust pipe and torque the nuts to 18 ft/lb (best done from underneath the car). Torqueing these can be more easily done after performing the next step (while it is held still).






DISASSEMBLY - Note the positioning of the exhaust manifold gaskets, then remove them from the threaded studs and discard them.
REASSEMBLY - Put all five of the exhaust manifold gaskets (FCP Groton Part #1366786 need 5) on the threaded studs. They will only fit on one way (and still line up with the port holes). The other side of the gaskets is black and kind of rubbery.






DISASSEMBLY - Remove the wiring bracket (10mm at yellow circle) that is connected to the transmission dipstick tube (to gain access to the bottom bolt for starter removal). Then remove the two starter bolts (14mm at red circles) that secure the starter to the bell housing.
REASSEMBLY - Replace the two starter bolts that secure the starter to the bell housing and torque to *25 ft/lb. Then replace the wiring bracket that is connected to the transmission dipstick tube.






DISASSEMBLY - Remove the starter bolt where the bracket is secured to the side of the engine (12mm).
REASSEMBLY - Replace the starter bolt where the bracket is secured to the side of the engine and torque to *25 ft/lb.






DISASSEMBLY - Disconnect the starter wiring. This consists of one green wire that connects via a spaded connection and one (13mm) nut that secures two red wires and one light gray (whitish) wire.
REASSEMBLY - Reconnect the starter wires as described above.






DISASSEMBLY - Remove the starter from the bell housing (pulling it straight backwards just a little) and lift it out of the engine well. Remove the plug (8mm Allen) from the access hole behind the starter. This is in the center of the picture and has a socket in it. Also note that you can now see the teeth of the flywheel in the right side of the picture. Having access to this hole and the flywheel is THE KEY to holding the crankshaft still while keeping everything in time. This access hole very much impressed me in terms of the engineering behind it (you'll see why later).
REASSEMBLY - Replace the plug in the access hole behind the starter (making sure it is snug enough as oil can leak from this if it's not) and replace the starter in the bell housing.






DISASSEMBLY - This line runs along the fender next to the timing belt. It felt and looked like it was basically styrofoam. I found that by twisting it I could unlock the front end going into the computer box, then twisting it again I got it free of the sleeve it attached to near the firewall. While this is optional, I found that it gave me a little extra room.
REASSEMBLY - If you decided to remove this styrofoam line, twist it back onto the sleeve near the firewall and then twist and attach the front end to the computer box.






DISASSEMBLY - Release the tension on the serpentine belt and remove it (which is easier said than done). The tensioner on my 850 has a hole in the pulley arm that is 3/4" square. But the problem is I didn't have a 3/4" drive rachet or breaker bar adapter, my serpentine belt tool set did not have a 3/4" adapter, and the 3/4" drive rachet I DID go and get was too big to fit into the very limited clearance between the fender and the tensioner. I bought the shortest length I could of 3/4" by 3/4" steel tubing from the metal stock (welding) section in our local hardware store. I cut the length that I determined would work, which was 1.5" long, and tapered all four edges down just a bit with a grinder, since the hole in the tensioner actually reduces in size a little as it gets deeper. I finally got it just right and could get it to fit about 1/2" deep into the tensioner. Then I just positioned it in the tensioner, adjusted a large crescent wrench to fit snugly on the tubing/tool, and rotated the handle toward the front of the car - releasing the tension so I could get the serpentine belt off. Whew! I actually distorted the steel tubing a little, so I think I am going to get a piece of solid steel stock and make the same tool next time.
REASSEMBLY - My belt (FCP Groton Part #9186352) was too long to route the traditional way shown in the Haynes manual. The belt routing I had to use was for the longer belt and it was very tight. The belt routing was as follows: Crank - AC compressor - Alternator - Idler - PS pump - Tensioner. The shorter belt routing is the same, except you have to switch the order of the Alternator and Idler in the routing. I noticed that there is a protrusion on the pulley arm that has a hole in it. This lines up (when the tensioner is "compressed") with a hole in the base of the tensioner so you can sort of lock it open while you route the belt around it. My tensioner did not have this (it was broken off), so I just had to route everything and hold it in place while making slack with the tensioner. I was at the END of the slack of the tensioner and still had to fight to get the belt around everything. I ended up getting it around everything but the PS pump, stretching the tensioner open, and then stretching to get the belt to barely start on the pulley for the PS pump (which I then rotated the pulley of to "thread" the belt the rest of the way on). A wooden yardstick is helpful in getting the belt to feed around stuff down low where it is hard to reach (I used my serpentine belt tool).





DISASSEMBLY - Remove both of the bolts (12mm) and remove the belt tensioner.
REASSEMBLY - Reinstall the belt tensioner and torque to 15 ft/lb.






When you start reassembling the components on this page, start at the bottom of this page and work your way to the top in reverse order, using the "Reassembly" instructions.


1 2 Page 4 - Timing Belt Removal 5 6 7 8 9 10



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(This tutorial is written, sponsored, and hosted by TracysTrueSoaps. I make quality, pure, gentle soaps that are also great at removing grime after working on a vehicle. Please support my site by checking out my soaps. People of all ages LOVE 'em [especially ladies] and they make great gifts for almost any occasion. Thanks so much!)