Guest bastaad525 Posted June 22, 2004 Share Posted June 22, 2004 Hey, I'm still alive!!! Heheh haven't really posted in a while Well after all the trouble, all the money, all the swearing... the damn motor is STILL/AGAIN leaking oil. DEFINATELY the rear main again. Just installed a new oil pan gasket again when I replaced the main bearings, and this time it is bone dry all around. This oil is definately coming out from the front of the bellhousing, and it's engine oil, not gear oil. So, the new rear main is leaking again. Now, when the tranny/clutch/flywheel were out, I made sure to get a good look at the end of the crank. See, I had just a few months ago paid this other guy to replace my seals (front/rear/oil pan, if you guys remember) and seeing as the rear had immediately started leaking after that, I figured maybe there was a groove worn onto the crank. But when I took a look there was NO groove at all, so the seal shouldnt have had any problems. And I saw the guy install the new one myself, certainly looked like he did it right... I've been taking cars to this tranny guy for a long time and never had problems with his work before. Something he did mention, and I've sorta suspected... maybe the worn thrust bearing and resultant play in the crank did a number on the rear main, both times now that I've had it changed? Maybe it's just moved around, or been worn super fast... either way... I"m pissed. Well over a grand spent on chasing down this problem (well.. and taking care of other problems that popped up while chasing down the leaks) and still leaking, still getting on my exhaust and burning, still making the car VERY unpleasant to drive (well, not all the time... it's not CONSTANT like it used to be... the leak is slower, so only occasionally will I smell that telltale smell of oil on the exhaust). So I gotta wonder now.. is it worth the estimated $300-400 more just to pull the tranny/clutch/flywheel and replace the damn seal AGAIN? Now that my thrust bearing is replaced and the 1.3mm of for-aft crank play is taken care of... a new seal SHOULD live out a normal lifetime. After doing the bearings on my back, I really dont want to try to do this with the motor in the car, and would rather pay someone else the $300 than try to arrange and take care of getting the motor out myself. Seriously... can I get a show of hands... how many of you guys have leaky motors? I mean... do you guys just let it be and fuggeddaboudit or what? Should I just let it leak? It's a very slow leak this time, not as bad as it's been before... usually I dont even spot any drops on the ground after parking, but every time I reach down and wipe of the bottom of the bellhousing there's some there. It just really bugs me.... should I bother? Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted June 22, 2004 Share Posted June 22, 2004 When you replaced the main bearings, you didn't replace the rear seal again? Hmmm.. Anyway, You may want to try checking the oil pan bolts again. I remember having an issue once with the ones in the rear of the pan which go through those metal "supports" (I guess that is what they are), that is if you used them... Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted June 22, 2004 Share Posted June 22, 2004 I agree that you should check the oil pan bolts again... and again... etc. If you use a torque wrench and tighten them to the 5-7 ft/lbs as called out in the FSM you will find that by the time you get back to the first bolt it is no where near the correct torque. The reason is that the oil pan gasket compresses a lot. I would Highly Recomend that you use a torque wrench and tighten them again and keep on tightening them until you achieve a consistant 5-7 ft/lb reading on every bolt. If you need to change your rear main seal again the best way (you will hate this part) is with the crank out of the engine, the second best way is with the transmision out of the way and the rear bearing cap removed, and the worst way (most common) is rip the old one out and hammer the new one in place then cross your fingers and hope you did not damage it. However you decide to do it be sure to put a thin film of oil on both the inner and outer side of the seal (inner contacts the crank shaft and outer contacts the block and bearing cap), think of this film of oil just like the one you put on the seal of your oil filter when you change it. A quote from one of my engine building books "if the engine is for racing any oil leak on the exterior is un-acceptable". You may not consider your engine a race engine but if you don't want a trail of yuck all down teh underside of your car you will get that taken care of. Dragonfly Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted June 22, 2004 Share Posted June 22, 2004 FWIW.... In adition to torquing to the correct spec each pan has its own pattern in which to tighten them. Kinda like how you would use a star pattern to tighten a wheel. When I worked for Ford we had a book which outlined the correct pattern for every type of pan beit oil / tranny etc for every make of Ford. Some of the patterns made no sense but seemed to work. Rufus Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted June 23, 2004 Share Posted June 23, 2004 On the pan - I am using the two metal support 'brackets', and I have retightened the bolts twice now. The reason I'm 99% sure it's NOT the gasket this time as I was last time, was that when it WAS the gasket, the oil would leak down all over the front plate of the bellhousing as well, and of course on lip of the oil pan, before finally pooling up on the bottom edge of the bellhousing. This time it's ONLY on the bottom edge of the bellhousing, there is none built up around the lip of the pan, none on the plate between the bellhousing and block. I didn't know there was a specific torque pattern for the pan bolts... was wondering about that but didn't see anything in the haynes manual about it. Should I NOT have used the two metal brackets? I dunno but I'm really sure it's not the pan this time. No I didn't replace the rear seal when I replaced the bearings. I replaced the bearings with the motor in the car, and didn't replace the rear as I was advised against trying. There was really no way to replace the seal at the same time w/o also pulling the tranny. And I didn't think I needed to replace it again even if I could have as it was just replaced a couple months ago when I replaced the clutch. Quote Link to comment Share on other sites More sharing options...
Sean73 Posted June 23, 2004 Share Posted June 23, 2004 Did you replace the side seals on the rear main cap? Sean 73 240ZT Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted June 23, 2004 Share Posted June 23, 2004 Those metal support pieces are not going to cause you any problems and you can leave them in place (they're braces). But I was thinking exactly what Sean73 said "did you replace the side seals on the rear main cap?" it is important that they be replaced as they get abused pretty bad by the removal of the cap. When those seals are replaced they should also get a thin film of oil, but it is also very important that the seal is pushed all the way down into the slot then the remainder cut off flush using a sharp razor blade, you then carefully drive the metal shim (that comes with the seals) between the seal and the bearing cap (the two small lips on the seal should face the block and the flat side of the seal should face the bearing cap). I also use gasket sealer on the pan gasket where it meats the rear main cap and cap seals to help ensure no leakage. Dragonfly Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted June 26, 2004 Share Posted June 26, 2004 sorry guys I should have been more clear. What I meant to say was, I did not replace the rear main bearing, as I was advised against trying with the motor in the car. Hence, I never removed the rear main cap, and didn't mess with the side seals. I did use copper spray on the oil pan gasket, to act as a sealant, as was advised buy a few guys here. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 27, 2004 Share Posted June 27, 2004 I have two things to add to this topic: 1) Did you LUBRICATE the seal upon installation with a smeared grease or assembly lube in the lip groove on the seal? If not, it's possible that it started DRY, and quickly smoked on startup, leading to a quick leak after initial startup. You can easily salvage a grooved shaft using a Chicago Rawhide or Federal Mogul "Shaft Saver Sleeve" which is a .003" think sleeve that is driven over the shaft while in place, with loctite on it's inner bore. They were designed for automotive harmonic balancer initially, and many shops now install them on NEW cranks or reground cranks so the seal area is a highly-polished precision sealing surface that is easily renewable at teardown whithout removing the crank or machining at all. It also adds .006 diametrical thickness making for more seal face pressure adding to sealing integrity (theough some argue more seal wear). Many people do not install seals correctly, and the faces of a rubber (say Viton) seal may reach temperature of over 400* well short of 15 seconds after startup due to the combination of seal face pressure and dry running straight on the shaft. This is also a good reason to pre-lube the engine with oil under pressure as opposed to cranking the engine with the plugs out until oil pressure comes up. Even cranking at 300 rpm can burn up an un-lubed seal. LUBE YOUR SEALS AS RECOMMENDED BY THE SEAL MANUFACTURER! 2) CHECK YOUR CRANKCASE PRESSURE! You may have excessive blowby or inadequate PCV action exacerbating seal leakage. The rear main is the closest to full pressure oil continually bathing the seal, and if there isn't adequate negative pressure in the crankcase, it will leak like a pig from day one, regardless of how well it's sealing. A single lip seal normally will seal up to 5psi differential, which sounds like a lot, but any installation deformity for misalignment can kill off that efficency. You may consider the possibility of a similarly sized seal with a dual-lip design if it's available. The Federal-Mogul catalog is immensely helpful in searching out compatible seals. The big thing is having the same outer diameter, inner diameter, and width. Usually width is "negotiable" and in some cases if a dual lip seal isn't available at say a 10mm width, it IS available at 15mm, and if the seal bore can accomodate the added depth of installation (or if it will tolerate a seal sticking OUT from the seal surface by 5mm) you can use it. Sometimes it's only a 1 or 2mm width difference that allows you to use a double-lip design over a single lip. Just some food for thought. Good Luck and keep us all posted on what you find. Were you at any of the convention activities last week? Saw John C at the Willow Springs Event.... Quote Link to comment Share on other sites More sharing options...
Guest Millerlife Posted March 17, 2007 Share Posted March 17, 2007 Is there a trick on replacing the rear main seal?. I already messed up one seal, and was hoping I can get an idea of an easy way of installing this new seal i purchased. Quote Link to comment Share on other sites More sharing options...
jrd Posted April 10, 2007 Share Posted April 10, 2007 I was having trouble stopping the oil leaks on my daughters Volvo. I replaced front and rear seals and numerous gaskets then a friend told me that a common problem on that engine is that the flame trap in the crankcase vent plugs up and the positive pressure in the crankcase will blow out the seals....sure enough, the crankcase vent was plugged. I cleaned it out and the thing quit leaking oil..... Joe Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 10, 2007 Share Posted April 10, 2007 Is there a trick on replacing the rear main seal?. I already messed up one seal, and was hoping I can get an idea of an easy way of installing this new seal i purchased. Yeah get a main seal installation tool. It's usually just a big round rubber stopper looking thing that you line up on the seal and tap with a hammer and it slides in. Also try using some oil around the seal while installing it. Quote Link to comment Share on other sites More sharing options...
Careless Posted April 15, 2007 Share Posted April 15, 2007 Yeah get a main seal installation tool. It's usually just a big round rubber stopper looking thing that you line up on the seal and tap with a hammer and it slides in. Also try using some oil around the seal while installing it. or you could buy some PVC pipe about the same size of the seal and just round off the edges. ive done that before. works ok =) Quote Link to comment Share on other sites More sharing options...
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