Where to start… purchased a 1999 S80 T6 4dr. Volvo sedan recently and knew it needed a timing belt. My long time mechanic, who is very able but NOT a Volvo specialist, assured me he could do this and proceeded to also change out the cam seals because it was evident they were leaking. Big no no unless you mark gears, cams etc… precisely or have the special Volvo cam lock tool that locks the exhaust and valve cams in place. The timing belt gears don’t key onto the cam shafts. This car also has the variable valve timing and hydrolic valve lifters. Oye! I’m getting a headache already. Long story short, he bought the cam tool, albiet after he didn’t mark anything. Applied the tool, put everything back together and it hasn’t run right since. Help! It has all the power it had but the engine runs very rough at idle and lopes(shakes) every 10 seconds or so. Now my wonderful mechanic, who is degreed by the way, and whom I like a lot, thinks valves might be bent due to low compression in four of the cylinders. I think he’s grasping at straws now but I’m getting exasperated. I think if valves were bent it wouldn’t run with full power like it does when test driving it. Or wouldn’t run at all??? This car also has a coil module at each spark plug. And has some warranty idle issues with a elec. idle module Volvo extended the warrenty on. But that doesn’t seem to be part of this problem…I don’t think anyway. Any clues? Help for a poor man with a Volvo?
sorry I would just go a dealer. do not wait for another problem. I feel for small shops the cost of keeping up with everything new is hard
I was at pepboys and watched three guys trying to get a tail light in. even this seems hard today. it sounds like the valves are off a little and the timing is changing to keep the engine running.
I’ve never understood why most people, including pro techs, won’t rotate an engine manually with a socket/ratchet after the installation of a timing belt and verify that everything is lined up properly before hitting the key and allowing a starter motor to do the damage.
It is possible to have a slightly bent valve or two which could cause an idle/low rpm problem and will then smooth out at elevated RPMs. If the mechanic is concerned about this kind of a problem then why does he not connect a vacuum gauge (about 20 seconds worth of work) and/or run a compression test, which is also very simple?
If the marks are correct, the compression is fine, etc. then the low RPM problem could be caused by an air leak (detectable with a vacuum gauge) or the idle module. The idle module is basically an air leak, although in theory it’s supposed to be a controlled one.
The marks could also be a tooth or two off and this could cause rough running at idle followed by smoothing out at speed.
If the vehicle were mine the first thing I would do is connect the vac. gauge and see what that shows. An air leak, low compression, bent valve, or whatever will be readily apparent.
If you cannot afford the dealer(affluent people can’t either who stay affluent) try an independent Euro shop with working knowledge on Volvo’s. Depsite their higher rates than general mechanics they can obviously save you money when they get into these situations due to their familiarity of working on Volvo.
Thanks all for responding. Update…no bent valves. Yes mechanic did turn the engine manually first. But the vaccum could be a problem as the vaccum booster seems to be bad (hard brakes). We’ll keep going at it. Thanks again…I’ll post the final outcome, hopefully it won’t be bankruptcy.