Erikinstockholm wrote:I spoke with the mechanic and not good. Basically the mechanic has cleaned the oil pan (Very very heavy sludge) and cleaned the oil pump filter which had some buildup. He put it back together, used synthetic and after 20 minutes, the light went back on. He then reopened the oil pan, replaced the oil pump with OEM Volvo refilled synthetic and again the oil light went on, not good : ( (had him do the timing belt as the car has 105k).
Then the mechanic thought that the oil return channels from the Head may be clogged as it seems that the oil is getting to the head and slowly draining back down to the oil pan. He opened the head and said to that of the oil pan- sludge and caked on old oil. He cleaned all this out and checked the oil return channels which appear fine. The rod bearings seem to be fine as well as the valve heads. Started the car and again after 15 minutes the light went on. Note that upon initial cold start the car runs fine, there is no sound of valve chatter, the light does not go on... It is only after about 15 to 20 minutes that the light goes on and you can hear valve chatter when revving the engine. While idle this does not happen.
Any idea from the forum? The mechanic is top notch, excellent knowledge inside out, he is baffled.. so am I.
Unfortunately, from the histories on forums, once the sludge is there the rod bearings start to wear which causes the low oil pressure. Try perhaps a thicker oil at least ..W40 or even ..W50






