Welcome to K-Jet.org, a site for Volvo enthusiasts. The site mostly focuses on 240-series cars with the Bosch K-Jet fuel injection systems, but there is plenty of information here for other models as well. Please note that this site is not affiliated with the Volvo Group; please see the Disclaimers for more information.
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Time to start chopping off heads! Metaphorically speaking anyway. After replacing the water pump, coolant, thermostat, radiator, temperature sender, and temp gauge on the ’78 242, I was at a loss for solving the overheating problem.
After some research, I decided that there were basically two remaining possibilities: a cracked headgasket or plugged coolant passages. Either way, it meant taking off the head. So, that’s what I did. I broke off two exhaust studs, and found that a third had already snapped in the past. I removed the exhaust manifold and just left it there, resting on the alternator (with the battery disconnected of course).
I removed the intake manifold with the eight nuts that connect it to the head, as well as the two bolts underneath that hold it to the vertical intake manifold support bar. Then the intake manifold could just be wiggled over, and otherwise left in place. I removed the valve cover, auxilliary air valve, and then the 10 head bolts that hold the head to the block. These were pretty tight, and required a breaker bar. On the front of the engine, I removed the timing belt cover, fan, and fan shroud.
Then, I just lifted off the head like so:
Then I took a look at the headgasket and the head/block. Lots of problems here, including some plugged coolant ports in the head, block, and headgasket.
So, I boxed up the head and sent it to R-Sport International for a cleaning, rebuilt, and mild port and polish job. I’m also going to use a Cometic multi-layer steel (MLS) head gasket that is thinner than the stock gasket on it to raise the compression ratio a bit for more power and hopefully some better fuel economy. R-Sport keeps these in stock as well. Later this week I should be getting the head back from the shop, so we’ll see what happens when I try to put this thing back together!