Hawklord Posted August 1 Author Share Posted August 1 Yes it is a 300TDI and worn pump/casing is looking to be the most likely culprit but looks to be a pain to replace as it is behind the cambelt which has only done 14,000 miles since the last change. Is there a non-return valve in 300TDI oil filters ? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 1 Share Posted August 1 There's no non return valve that I'm aware of. Quote Link to comment Share on other sites More sharing options...
joe1 Posted August 13 Share Posted August 13 Wear in the pump rotors or housing is unusual (have a look what Britannica restorations says about them on YouTube too). I'd be more inclined to start looking at oil (da2376?) pressure relief valve - if the spring is weak then blow off will happen early. Examining the spring means sump off to get access to the humungous 1 inch slotted screw holding it all in - the WM specs on the spring lengths are wrong though! Other odd suspects might be wear on No1 cam bearing (if cam belt is overtightened beyond 12 Nm wear can be provoked - the bearing will then have a step in it created by the cam. This is quite common! Other ideas...What about an under performing radiator leading to higher temperature and thinner oil? Or clogged oil pickup in the sump. Your idea about using 20/50 might be a good temporary measure though .... Quote Link to comment Share on other sites More sharing options...
Hawklord Posted August 13 Author Share Posted August 13 I have already replaced the pressure relief valve and spring and checked the pickup pipe. Having replaced the oil pressure sender and gauge with a VDO one my oil pressures although not brilliant are reading higher and opinions in earlier replies seem to be acceptable for the high mileage my engine has done. My annoying issue is the oil draining issue when the vehicle is left standing. Are there any negatives for using 20w50 instead of 15w40. Quote Link to comment Share on other sites More sharing options...
joe1 Posted August 15 Share Posted August 15 20/50 is for non turbo engines really - a turbo requires slightly thinner oil which is why 10/40 is specified. Do you get same problem in winter? Could try the 20/50 in summer and revert to 20/40 in winter - at least your engine gets clean oil that way 😀 Is oil draining back into the sump from the oil pump? (checking level on dipstick at end of day and start of next day might give a clue. And what about the thermostatic valve for the oil - if not working oil will get hotter and thinner (but would not explain your pressure from cold issue) Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted August 15 Share Posted August 15 (edited) When I was in Africa, they gave me SAE50 Singlegrade. No problem if you don't have to much coldstarts and drive very carefully warm. But nothing for all the time Edited August 15 by Sigi_H Quote Link to comment Share on other sites More sharing options...
fmmv Posted August 15 Share Posted August 15 I think you need oil that meets cf4 spec to get the right detergents, apart from being 20w/50. In really cold weather it will take longer to build pressure than say 10w/40. Why not look for a 15w/50 if hot oil pressure is the problem. Maybe try a different make of filter, I know Mahle is considered good, but just to eliminate it from inquiries? Quote Link to comment Share on other sites More sharing options...
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