How To Replace The Head Gasket On A Volvo 850 (page 8)

(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!)

Cylinder Head Replacement

This is what the head surface and valves looked like before and after the machine shop worked on it. They machined the head, did a valve job, and put my new valve stem seals (FCP Groton Part #3517893 need 20) in for me. The head was really immaculate when I got it back, as you can see. I was expecting a smooth-as-glass finish (like when a brake rotor is turned), but I've learned there needs to be just a little texture to "grip" the head gasket.

After having done a thorough job of cleaning the surfaces of any gasket material, it is time to put the new head gasket on. First, make sure to clean any oil or residue from the surfaces of the block and the lower portion of the head that will contact the head gasket. This is best done with something like acetone and a lint-free cloth. The acetone will dissolve and clean away any oils, residues, etc. and it evaporates very quickly, leaving no residue behind. Also, go ahead and reinstall the lower thermostat housing (T40) with a new gasket (FCP Groton Part #9463274) to the lower portion of the head before mounting the head on the block.

Here is the new head gasket (FCP Groton Part #3531017), coated with the Permatex Copper Spray, and positioned properly on the head. Note the projected sleeves around the bolt holes in two locations, at the 4:30 corner of cylinders 1 and 5, and make sure to align the head onto them when you place it. Before you place it, you might want to familiarize yourself with the weight of it and the positioning you are going to have to do. You may want someone to help you lift it and place it to make sure you don't slip and damage something (or yourself). I did it by myself, but I am a pretty big guy.

This is the sequence for installing and tightening the new head bolts (FCP Groton Part #6842347 need 12). Once the head is properly positioned on the block and the gasket is noted to have stayed in the correct position, undamaged, the head bolts can be installed. This sequence is backwards from when we were removing the old head bolts. This time you start tightening in the middle, working your way out diagonally as indicated in the numbering in this picture. You want to make sure you are using new head bolts and not any of your old ones that might accidentally get mixed in. Here is a picture of one of my old head bolts and a new head bolt side by side. You can see that the old one actually stretched a little from being used before. If you try to use old head bolts, you very well may break one off, or have an inadequate seal from the new head gasket somewhere down the road.

	I know this may seem like a very simple thing, but labeling the correct torque sequence next to the bolt holes helped me easily keep track of which I had tightened and which I had not. Here you can see the 1, 2, and 6 of my numbering I wrote on the head with a Sharpie.

Before inserting each head bolt, apply a thin coat of clean engine oil to the threads, the shaft, and the underside of the bolt head. I found the easiest way to do this was with a blue paper (shop) towel that was saturated with clean engine oil. I wrapped the oily part around the bolt and turned it a few times in my hand, making sure the whole bolt was just barely shiny from the underside of the bolt head to the tip of the threaded end. This helps assure a smooth application with accurate torques. I then installed the bolts (using the correct sequence above) one at a time and just tightened them finger-tight with the extension and a 6 point 14mm socket.

Using the sequence above (that starts in the middle of the head), torque all the head bolts to 15 ft/lb. Once you have finished, repeat the sequence and torque them to 44 ft/lb this time. NOTE - if you have a US Haynes manual that states the second torque should be 37 ft/lb (as mine does), it is INCORRECT. I also had a British Haynes manual and a Volvo factory manual to refer to, and both of them gave a Nm value that converted to 44 ft/lb. I further researched and found from another source online (AERA page 116, second line, last column on the right) that the second torque should be 44 ft/lb. I have communicated with Haynes and notified them of the error, and they agreed. So, torque to 15 ft/lb the first time through the sequence, and 44 ft/lb the second time through it. The third and final torque is the one that is a nail-biter, and it is done with a torque angle gauge (above). This is basically a short 1/2" drive extension with a dial around it showing degree measurements (0-360). It has an arm that protrudes from a bracket on the dial so it doesn't move, while the clear cover on top of it has an indicator line that shows exactly how much you have tightened (in degrees). I got mine on ebay, as I couldn't find one locally.

Here you see the setup I had to use to have the correct height for reaching the head bolt and to be in the correct position to use the torque angle gauge (that has to have something to anchor to). I had to use a 1/2" to 3/8" drive adapter - plugged into a 3/8" deep-well 6 point 14mm socket. This setup worked fine, as you can see in the other picture. In the second picture, you can see how this gauge works. The dial is held from spinning by the anchoring arm that is kept from rotating by the hole it is hooked into. But the drive portion and the clear screen with an indicator mark can rotate together. So it is secured as shown, the clear screen is rotated until the indicator is on "0," and the appropriate angle measurement desired is tightening to with a 1/2" drive breaker bar. Once this is secure, go back through the tightening sequence a final time and tighten the head bolts an additional 130 degrees. This is only a little more than a third of a turn. But after tightening them to 15 ft/lb, then 44 ft/lb, this final torque was a nail-biter to me. All of my life, I have always stopped tightening a fastener when I would hear ANY kind of squeaking or creaking (to avoid breaking the fastener). But pretty much the whole 130 degrees of this final torque, there were some wicked creaking and groaning sounds going on. This is normal and is what stretches the head bolts so that they work the best (torque-to-yield bolts), but my read-end was still drawn up so tight that you couldn't have driven a nail in it. But none of them broke (the gnawing fear I was having) and everything worked just as it should have.

Now it is time to put the top portion of the head back on. First, put the five spark plug O-rings (FCP Groton Part #1397525 need 5) around the spark plug ports in the little depressions they go in on the lower portion of the head. If you have a couple that won't lay completely flat, just leave them on the head in the sun for a few minutes and they will limber up. Although I am showing and describing the step of applying the sealant in the next picture, I would encourage you to look through the next couple steps before applying the sealant. Familiarize yourself with how you are going to secure the camshafts, what you are securing them with and where it's at, where your lube is (moly grease), etc. It takes long enough to just apply the sealant (which is done before securing the camshafts in the upper head) and you don't want to drag your feet on the rest of the steps before installing the upper head and end up with sealant too dried out to work. I think it took me about 15 minutes to apply the sealant completely, then another 5 to get the camshafts ready and lubed. Mine sealed up fine, and has not leaked in the 700 miles or so since I did this, but we were having a lot of humidity around here and that may have helped to keep the sealant from "skinning" a lot. I used the sealant from FCPGroton (FCP Groton Part #1161059) and it worked fine. But it did not appear to be applied the same way as the factory sealant, which appears to be more of a liquidy sealant that you can roll on. The way I applied it was to run a small bead everywhere I could in a given area and then go along patting it with my fingertip quickly and lightly like tapping out a telegraph or something. This spread it out and left a nice, tacky finish (picture). As I squirted a bead of sealant out, I would leave more on bigger areas than on smaller ones, and would leave none on tiny areas - but would transfer the extra from another area to it via my fingertip. This stuff is thick and a little effort is required to squeeze it out fast. It has one of those sardine can clips that slides on the end and keeps it rolled up and coming out (like you may roll your toothpaste tube up).

Keeping any of it from getting into or onto your sealant, put a little dab of moly grease (like multi-application axle grease in a cardboard tub) on each of the journals where the camshafts will contact the upper head. After installing the camshafts onto the upper portion of the head and securing them (as in the steps below), put a dab on each of the cam lobes (oblong areas) and on the camshafts where they will contact with the journals in the lower head. This is to have some type of lubrication (after these have been degreased and cleaned) in those areas when they start rotating later (during timing belt installation, initial startup, etc.)

Place the camshafts in their correct positions, with the exhaust camshaft on the back closer to the exhaust manifold studs, and the intake manifold on the front. Remember, the groove on the intake camshaft is ABOVE the seam of the head, while the groove on the exhaust camshaft is BELOW the seam of the head. This picture was turned around 180 degrees since I was holding it upside down when it was taken

Here you see the bracket used earlier to hold the camshafts in place with the steel stock pieces in the grooves and a distributor and cam position sensor bolt holding the bracket on. The other end of the camshafts is secured with the wire coat hanger used earlier.

Mount the upper head section in place on top of the lower section, with all dowels lining up as shown. Apply clamps to hold down the top head section while the 40 bolts (10mm) are installed. I installed my bolts barely finger-tight, then used a sequence like the one for tightening head bolts to go back over them (working from the center outward). I also made sure the clamps were clamped down tight each time so that the bolts weren't having to do the work. Each time I went back over the 40 bolts, I would spin the bolt with just the extension and my fingers (barely finger-tight). Each time I went back over these, I would find that a lot of slack had accumulated that I could take up with finger-tightening. It is important to let the clamps do the majority of the tightening here, so that the bolts don't get strained, stripped, or broken. Even though I was just finger-tightening, I had one bolt in the middle on the back side that sort of stripped, but is not leaking. If I do anything with this again I will probably drill out the threads and tap that hole for a bigger bolt.

After cleaning all the remnants of old gasket off and cleaning the mating surfaces well, apply the new gasket (FCP Groton Part #1236119) and replace the water pipe (10mm) on the rear of the head and torque to *15 ft/lb. NOTE - Since these mating surfaces are very close together once the head is replaced, I flexed the water pipe back just a bit, threaded the top bolt through (sticking the top part of the gasket in over the bolt as it went through), then let the gasket swivel on the top bolt into correct placement for the bottom bolt.

1 2 3 4 5 6 7 Page 9 - Timing Belt Replacement 10

If this info has been helpful, please consider making a donation.
Even a dollar or so would be greatly appreciated, thanks!