Hey im new to the forums, ive recently bought a 1990 740 Turbo. The car is in good shape, when i bought it i did a general tune up. Changed the oil, new plugs, wires, air filter, and recently put a dynomax muffler on it because the stock had eroded and wouldnt pass inspection. Car ran great for about a month or so, and i didnt abuse it.

About a month ago, maybe three weeks, it started knocking. Not too bad but now its at the point of sounding like a diesel almost when i start it up... im fairly sure its one of the main bearings on the rods, ive changed them before in a V8 but this engine is considerably different. Can i change them without pulling the engine? I have the haynes book but it talks about all of the work with the engine upside down lol and at this point i dont even have a car jack where im living, or even a cement pad to put the car on. I could find somewhere to do the work if it is as easy as a V8 would be, just lifting the car up and changing the bearins one at a time, but is it? I called the volvo dealership and they quoted me 3000 for just the labor and told me to sell the car for parts ... and then tried to sell me a used car, *** holes. Ive priced the bearings at about 80-90$ and would rather do it myself. What would be the easiest way of doing them? And, having drove it for 3 weeks or so have i ruined my crank now? Any info is awesome. Thanks!

 

Usually, a diesel-like sound is a result of valvetrain noise or fuel injectors, this isn't all that uncommon in redblocks. Does it knock consistently at mid-range RPMs? Rev it to 2,500rpm or so and feather the throttle a bit, does it knock when you let off? Or does it just tap a little at idle and rattle on startup? If you answered the latter, it's probably just the valves and lifters, a valve adjustment may be in order. If you answered the former, check the compression and do a bleed-down check, piston slap is also common in high-mileage redblocks which haven't been maintained well and low compression along with excessive bleed-down can indicate a poor seal caused by worn rings.

 

+1. Too soon to tell. Checking valve clearances every 30k mi is a maintenance item. A qualified mechanic with a stethoscope can tell a lot. I would have it diagnosed by a Volvo mech before tearing it down.

 

so, ive determined its probably the valve train, how would i go about adjusting the valves? the valve cover is in an easy to reach spot, and a gasket is cheap, what kind of tools do i need to adjust them, and will it be obvious after i do it if that was in fact the problem? The sound seams to be kind of inconsistent, its sometimes when the car is cold and sometimes when the car has warmed up, but not all the time either way. Also, how hard are ball joints to change on these wagons? i think mine are going out, when i go over a bump at low speed especially the suspension makes a clicking sound. ive had a mechanic check it out, he wants to charge me 350 for the valve adjustment and ball joints. Although that isnt that much money im debating just selling the car, as much as i do love it, im moving to California soon from VA and the drive im sure will claim the car, and putting 350 into it so it MAY make it will be as much as a plane ticket... anyways, info on that stuff would be awesome, i can work on cars i just dont know where to begin on this stuff and have limited tools. thanks guys.