505 GTi ZDJL Main Bearing Cap

[Simon W]

I'm in the process of fixing engine oil leaks while doing a gearbox change....No 1 main bearing cap appears to be leaking at the seal points where it is supposed to mate with the sump gasket, I think someone has replaced the sump gasket previously and may have damaged those seals, so used some orange coloured silicon type (I think) gasket sealant but this hasn't done the job.
I have the box out, the flywheel off and the sump off (engine still in car), and have the little 'matchstick' type seals to fix the leaks...however, my attempts to undo the No1 main bearing cap bolts have me wondering if they are left hand thread. I see no mention of that in the Haynes book, but I used a breaker bar with socket and estimate that I would have applied at least 150 ft/lbs of torque which should have been more than enough to budge them. Each made the release 'crack' sound/feel as I applied the torque initially (probably at about 100 ft/lbs), so I thought I had them, but then nothing happened as more torque was applied. I don't want to go too much further with torque before checking that they are not left hand. Unfortunately, I don't have an impact driver. If any one has any info, I'd appreciate it....I don't really actually want to remove the cap, as it creates all sorts of risks, but it seems to me it's the only way to fix the leak.

 

[Simon W]

Update on initial post:

Clean down reveals that the major leak source was actually the rear main seal (crank). I believe the gearbox input shaft seal was also leaking a little, adding to the mess. I think there may be a very slight leak around the No1 main bearing cap seal which I think can be fixed without removing the cap itself...making my post somewhat redundant, although the main query regarding the thread sense on the bolts is still relevant, and this creates a few new questions in my mind.

1/ In my unsuccessful efforts to undo the No 1 main bearing cap bolts, I heard and felt a slight crack on both bolts. Assuming the bolts are not LH thread, I didn't think that thread locker is used on those bolts, but if it is, I have obviously broken the lock (the 'crack) and so would need to remove the bolts and reapply thread lock. If thread locker isn't used, then I think I would need to retighten the bolts since I did hear/feel the 'crack', despite being unable to move the bolts at high torque. If I simply used a similar torque in the tighten direction but still get no movement, would that be satisfactory confirmation that the bolts are ok to leave at that?


2/. The main seal leak was a bit of a surprise since the leak started not very long after it was replaced. Not sure why it failed, it was the right/genuine one...expensive. I checked the shaft face, it looks good, no damage, not worn no scratches or pitting. The only thing that might have been an issue with it was the depth the seal was set at, and whether or not it was perfectly evenly pressing in. Should I clean up the face of the shaft where the seal lips sit, and if so, what with? I also wonder how deeply pressed in the seal should be (old one had about 2mm of shaft face protruding beyond the seal's outer lip, but was that enough?) ... and are there any tips on how to get it seated perfectly true (old seal took a bit of work to get out, so probably isn't much use to use as guide)? And if I lube the new seals lips with the clean, new engine oil, as I have always done, is that enough, or is there something else recommended?


Thoughts, suggestions and ideas eagerly sought.

 

[dacia4x4]

Normally thread lock/Loctite would not be used on main bearing bolts,but who knows if previous history has someone using it on bolts.I would remove each bolt individually and clean threads and retorque to correct specs seeing bolts have moved,not sure how many degrees.have you checked the seal for directional lines at lip area?as many years ago had seal supplied for distributor drive shaft on 505 sti which had incorrect directional lines on it.also is crankcase breathing clear and not pressurising crankcase causing leaks?.jim

 

[Simon W]

Normally thread lock/Loctite would not be used on main bearing bolts,but who knows if previous history has someone using it on bolts.I would remove each bolt individually and clean threads and retorque to correct specs seeing bolts have moved,not sure how many degrees.have you checked the seal for directional lines at lip area?as many years ago had seal supplied for distributor drive shaft on 505 sti which had incorrect directional lines on it.also is crankcase breathing clear and not pressurising crankcase causing leaks?.jim

Thanks Jim....this engine hasn't been rebuilt, it would be factory on the crank fasteners, so I don't believe any thread lock would have been used. Do you know if the bolts are right hand thread? I have applied a lot of torque to undo them already, so need to be sure I am not going the wrong way! The engine is breathing ok, I think the seal was just not fitted as well as it should have been. I'd like to lightly clean the shaft where the lip rides on but not sure of the best thing to use for that, any ideas on that?

regards and thanks,
Simon

 

[dacia4x4]

Hi Simon,yes main cap bolts are right hand thread,I would apply a light dose of oil on threads when reassembling.the sealing surface I would use some wet and dry,say 800 grit with petrol to clean surface with where rear main seal runs on crank..jim

 

[jo proffi]

I am by no means an expert on this engine, but if it is the same donk as the renault 2.0/2.2, I have rebuilt three or four and do not remember anything being left hand thread. In fact i dont remember any fastener anywhere being so. I do remember initialy stressing about the load used to undo stuff.
I also dont remember ever seeing a main crank mating surface that was in good condition and always re sleaved them, with great difficulty i might add as the sleaves were always a little too long and needed some adjustment to make fit perfectly. That is a delicate job indeed!
The main seal was always a prick to get seated straight, and I always had the luxury of doing the job with the engine on the stand, so I'd imagine it would be an absolute #$%@ of a job to do with the engine in the car. I think I had a special tool to help locate the seal, like a massive socket that made squaring it up easy...well, easier.

I also redesigned the crank breathing system quite extensively to be negative pressure and never saw an engine oil leak in the non pressure part of the engine, except for the back end of the head in the oil pressure zone, which i threw away torquing convention and nipped up a little tighter.
I wouldn't be overly concerned about snapping bolts or pulling threads. Famous last words, I know, but these donks are pretty well built in regards to the strength of the components. 2.0l are strong.. 2.2 are ridiculously so.

 

[Simon W]

Hi Simon,yes main cap bolts are right hand thread,I would apply a light dose of oil on threads when reassembling.the sealing surface I would use some wet and dry,say 800 grit with petrol to clean surface with where rear main seal runs on crank..jim

Hi Jim,

Thanks...success, managed to back the bolts off with the help of a fence post and a hammer! Probably would have taken two minutes if I had an impact driver. It wasn't helped by the fact that a lot of torque effort was lost due to engine mounts twisting.

I noticed that my earlier thoughts were really just wishful thinking, there is definitely a leak out of that main cap side seal, and maybe the rear main seal wasn't the big culprit after all. Someone had cut the little side seals off too short, for whatever reason (under a previous owner), and obviously had tried to seal it with sealant without removing the bearing cap, so no wonder it didn't work. I knew in my gut that it had to be taken off. Anyway, I can do the proper fix now, and rest easy in the knowledge. Thanks for your suggestions, will do those things. Have a great day, and thanks for taking the time to help.

Regards
Simon

 

[Simon W]

I am by no means an expert on this engine, but if it is the same donk as the renault 2.0/2.2, I have rebuilt three or four and do not remember anything being left hand thread. In fact i dont remember any fastener anywhere being so. I do remember initialy stressing about the load used to undo stuff.
I also dont remember ever seeing a main crank mating surface that was in good condition and always re sleaved them, with great difficulty i might add as the sleaves were always a little too long and needed some adjustment to make fit perfectly. That is a delicate job indeed!
The main seal was always a prick to get seated straight, and I always had the luxury of doing the job with the engine on the stand, so I'd imagine it would be an absolute #$%@ of a job to do with the engine in the car. I think I had a special tool to help locate the seal, like a massive socket that made squaring it up easy...well, easier.

I also redesigned the crank breathing system quite extensively to be negative pressure and never saw an engine oil leak in the non pressure part of the engine, except for the back end of the head in the oil pressure zone, which i threw away torquing convention and nipped up a little tighter.
I wouldn't be overly concerned about snapping bolts or pulling threads. Famous last words, I know, but these donks are pretty well built in regards to the strength of the components. 2.0l are strong.. 2.2 are ridiculously so.

Hi Jo,

see my latest reply to Jim on progress, in short, bolts have been budged, no breakages, no blood but maybe a small bruise or two! I was sure they had to be rh thread, but the amount of force it took was a lot more than I felt happy with, so wanted to be absolutely sure.

I've had a pretty good look at the crank mating surface, and don't see any issues, but will rub it down lightly with some 800 grit and see how it looks then. Sleeving in situ would be a nightmare, it really would require the engine out, I think.

thanks for your help,

Regards
Simon

 

[dacia4x4]

Just be careful in fitting rear main cap side seals,I used to makesure they were well lubed on sides of contact with block and main cap so they would not be drawn up a little and leave a gap at seating point of engine block,something to check when fitted that there is no gap at point where seals meet engine block base.joe may have some advice as to this area as well from his experience.also I usually cut seals a millimeter or so proud of block as seal may contract a little from being dragged down between the two parts ( block and cap)..jim

 

[Simon W]

Just be careful in fitting rear main cap side seals,I used to makesure they were well lubed on sides of contact with block and main cap so they would not be drawn up a little and leave a gap at seating point of engine block,something to check when fitted that there is no gap at point where seals meet engine block base.joe may have some advice as to this area as well from his experience.also I usually cut seals a millimeter or so proud of block as seal may contract a little from being dragged down between the two parts ( block and cap)..jim

Thanks Jim,
yes, the book says use some celluloid tape as a slide for the seals, but a tiny bit of oil, or even a minute smear of vaseline also makes a lot of sense to me. It also says to cut the seals off at 2mm proud, so will do that.

cheers ...Simon.