jackmac Posted February 20, 2014 Share Posted February 20, 2014 Hi all, In August I had to replace the big end bearings on my 300TDi after it emerged that the previous owner had apparently not torqued them up, leading to them coming loose. Since then, I have enjoyed about 2500 miles (at most) of engine trouble free motoring. Unfortunately, on the way back from a pay and play day recently the oil warning light came on. I pulled over straight away, confirmed there was still plenty of oil, and got a recovery truck home. When the light came on, the engine was running quite hot (about 3/4 on the gauge, no doubt partly due to mud in the radiator) and I didn't seem to have the same amount of power as I had done on the way to the event. Just been out in it again tonight, managed about 10 miles and then the warning light starting flickering very faintly just as I pulled up at home. I've ordered a new oil pressure sensor which I will fit this weekend and take it out for another drive. I don't expect it to fix the problem at all! I suspect that either the big ends have gone again or the main bearings have gone. When I fitted the big ends, I noted that the mains were not properly torqued up, but when properly torqued I couldn't turn the engine over. Being a bit short on time, I just put them back to the torque I found them all at. If the new sensor does not fix the issue, I plan on fitting a new set of big end and main shells to try and get another couple of thousand miles out of her before changing the engine out. I don't have the money at the moment to change it, or to send the crank off to have it checked and possibly reground. My question (got there eventually) is: how much of a job is it to change the main bearings on a 300TDi? I know I don't need to remove the crank as I can slide the new shells around it, but can I access all of the nuts & bolts to remove them without having to split the engine and gearbox? Quote Link to comment Share on other sites More sharing options...
western Posted February 20, 2014 Share Posted February 20, 2014 possible the previous owner who built the engine has used the wrong size bearing shells, it shouldn't lock up when the correct size shells are fitted. Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 20, 2014 Share Posted February 20, 2014 ^^^^ What he said ^^^^ I had exactly the same thing happen to me several years back on a Ford V6. Guy had used undersized bearings by mistake.. Though how he failed to notice this ive no idea. You'd have thought he would spin it over by hand after torquing up the bottom end?? Quote Link to comment Share on other sites More sharing options...
mmgemini Posted February 20, 2014 Share Posted February 20, 2014 Exactly what has been said. The mains are easy to change, like you said slide them out. What size were the big end shells ? I would expect the mains to be the same but not taken for granted. What state was the crank in when you dropped the big ends. When I lost oil pressure, oil pump failure. Only one bearing surface on the crank was badly marked. I've done over 4,000 miles since I botched that one up. Quote Link to comment Share on other sites More sharing options...
jackmac Posted February 20, 2014 Author Share Posted February 20, 2014 So I don't need to take the gearbox off to access them all? Big ends were standard, the crank was not reground when engine was rebuilt. I thought the crank looked pretty good. There were some very slight marks on one of the journals, shells removed from there were very heavily scored by some kind of foreign material. Quote Link to comment Share on other sites More sharing options...
jackmac Posted February 21, 2014 Author Share Posted February 21, 2014 Have now discovered that the front crank seal appears to have gone as well. Looking like it might be uneconomical to repair it now as the cost of parts is rapidly rising. If anyone has a 300tdi they are looking to sell, let me know! Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 22, 2014 Share Posted February 22, 2014 I would tend to err towards repairing your own engine properly over spending money on a 2nd hand replacement that may also need some work... Just a thought. Quote Link to comment Share on other sites More sharing options...
JeffR Posted February 22, 2014 Share Posted February 22, 2014 I would tend to err towards repairing your own engine properly over spending money on a 2nd hand replacement that may also need some work... Just a thought. Better the devil you know... Quote Link to comment Share on other sites More sharing options...
mmgemini Posted February 22, 2014 Share Posted February 22, 2014 Engine out. Tip it on it's side and sump off. You'll soon have the crank out. Get it away and get it measured. That way you'll get the correct size shells for the mains. Quote Link to comment Share on other sites More sharing options...
Jode Posted February 23, 2014 Share Posted February 23, 2014 And you can get the journals reground if necessary - you mentioned one was slightly scored. Quote Link to comment Share on other sites More sharing options...
jackmac Posted March 8, 2014 Author Share Posted March 8, 2014 Following on from this... Crank needs a regrind, thus needs to come out. To do so, I think I need to remove the timing housing. But for the life of me I can't separate it from the block? Tried driving a flathead between them, tried hitting it quite sharply with LR tool no. 1... I daren't hit it any harder! Any ideas why it's not coming off? All the bolts are loose, camshaft pulley hub is off Quote Link to comment Share on other sites More sharing options...
jackmac Posted March 8, 2014 Author Share Posted March 8, 2014 Nevermind, missed a bolt in the 10mm thick coating of oil and mud in the timing case! Quote Link to comment Share on other sites More sharing options...
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