rebuild oil leak

[studabaker]

second time this leak has occurred. I have a polished crank and cleaned block with over sized bearings. It seems that maybe oil flow through the engine is being impeded or not flowing right? I replaced the rear main seal which was beyond my abilities as a novice. there were minor holes in the sealing part against the crank. It is dripping from my oil filter which I already fixed from the position sensor. I pulled it and put sealant around it. That has never leaked on me before. I must have put something back together wrong when I rebuilt it my self because I am an amateur at this and going from instructions I am finding without actual mechanic training.

What could I have rebuilt wrong that would cause the rear main seal to pop and the crank position sensor to pop?

 

[jayson427]

Make sure your pcv system is working properly. If you don't install the the rear main just right it will leak no matter what. Google pcv on the 420a other then that torque issues maybe?

 

[studabaker]

thank you,
I got a new stock intake and what i believe is the pcv hose that goes to the intake from the valve cover is stock and functioning properly. The more suspect is my rear main replacement.

can you elaborate on "just right" ?

I used the old one to seat it and put some oil on the inside and some rtv on the outside. It was a tight fit. I barely started it and turned it off. I looked at the engine for a second with no immediate leaks until the next day when there was a pool and some from the oil filter to the transmission. Ill check the pcv more thoroughly.

Could a clgged oil filter cause this? This is what it seems like to me that there is a blockage in the oil system. The oil filter was new. So much easier test than rear main seal. Thats blown again but maybe it wont dump so much?...

Except that the oil filter is before the block in oil system.
could it be that i over sealed my oil pump and caused double pressure by clogging a oil path? Oil is getting to crank maybe not somewhere else?

By " just right" do you mean that if i seated it all the way against the block that it would leak? I need to install it a few mm from being against the block?

 

[VelocitàPaola]

There's an o-ring between the block and bedplate right near the oil filter housing, and of course, there's another o-ring between the oil filter housing and the bedplate. They're both easy to forget, but a leak will result if either are omitted. The oil filter housing o-ring is easy to replace, but unfortunately the bedplate o-ring isn't; you have to pull the engine and drop the bedplate.

Corbin made a really thorough rebuild guide many years ago. You should reference it the next time you rebuild a 420A:

http://www.2gnt.com/index.php?d=A_Proper_Rebuild

 

[studabaker]

That is a good link and I will use it later.
I am going to replace the rear main again because Ive read in several places that by seating it all the way against the block the seal against the crank might not be correct. This post is validated by this not being a common detail, or clear enough and a problem others have had. I very well may have lost the bedplate ring but that would not have cause the 100 ml of oil that leaked from the other side. Short of having the block cleaned again this is my best idea of the solution. To seat the rear main seal such that the rubber is on the crank. The crank has about a few mm between the block and if the seal is flush some of the rubber is in that gap and fails to seal...
I appreciate your advice and may need more if or when I try to put on a turbo.

 

[BoostforBreakfast]

you most likely used the "factory service" diagram about how to apply the red anaerobic sealant between the bedplate and the block. It is actually wrong and shows to apply on the inside of an oil passage near the oil filter when in fact you need to go around the entire passage.
First time I built a 420a-style engine I did the same thing. Gushed oil out of the back. Had to pull the motor and remove the bedplate and redo the sealant

 

[Lou98GSX]

there is a procedure to install the rear main seal . first you don't put any lube on seal . then there is a special cone shaped tool that has a magnet on it that goes on the crank . next you slip the seal on the tool cone then you put the cone on the crank then the metal cup on the seal and slap it in with a hammer . seal has to go in dry .

 

[BoostforBreakfast]

if you use a hard rubber or soft brass hammer and evenly set the rear main with even taps, you should be good. I've never had an issue with that method. U make sure the spring is still in it?

 

[Lou98GSX]

i don't believe that seal has a spring its a different style seal . it has a large lip that seals itself as the crank rotates . i have changed many on 2.0l neons .

 

[BoostforBreakfast]

you're probably right. I think I'm thinking of the cam seal on the sohc's. Its been a few years since I've built one

 

[studabaker]

Pictured is the premium one i used and am replacing with the same. There is another one with more rubber. Never had any problems with it until i installed it flush to the block. The other egine has a bracket which holds the seal away from the block in correct position. It is a tight fit and I actually installed it the first time with the bed plate but not in correct position flush to block. I am confident this is the solution especially given the change to the next generation engine with the bracket holding this seal.
open side to block fyi.

third picture is first bad installation with the more plastic type. It needs to be more flush with the lip on the block than recessed as pictured, which is leaky.

oil between the crank and seal couldnt hurt and rtv on the outer diameter couldnt hurt but mixing those up might cause a problem.
I dont think either is necessary.

 

[studabaker]

So I am still leaking oil. It had to be something in the bedplate with the oil pathways.

 

[studabaker]

I have basically disassembled it and reassembled it. Previously I did not install an o-ring just above the oil filter in between the bed plate and the block which caused one small leak. I am confident that the other leak was from installing the rear main seal improperly. From the picture attached you can see that the end of the crank is about the thickness of the seal and if there is any of the crank exposed on the clutch side then the seal is that much over the inside edge which I believe has caused my leak. I have just installed the engine and am taking a break but I am confident that I have resolved my leaks. The only other issue is that it is recommended to install the rear main seal after bedplate to prevent "pinching" however I have done it this way because I want to be more sure it is aligned than I am concerned about pinching it. This seal is metal on the outside and there is no plastic that I expect might pinch either.

 

[studabaker]

So, wow, its been years and I just started her up again and the rear crank seal is holding and the engine is running good. A little high idle but the basics are there. I still have this dripping oil leak from what I think is a sensor in the back. Maybe causing my high idle as well. I am including a picture of the sensor. I will be researching this sensor and torque specs for installation. Maybe I tightened it too much. it was a pain to get to I remember that much.

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Upon replacing the oil pressure sender thing which is where oil appeared to be leaking from it it again. I had researched that it is a relatively common thing and only ten dollars. It is running funny like fast or high idle. I am looking into that but as soon as the battery was pulled it should have reset so there must be something causing this idle issue. I am going to try an oil gauge aftermarket as well to see if i can get it to hold oil long enough to id any timing issue. or possibly just a bolt. 1 1/16th deep socket gets it out from the bottom, a 1/2" drive ratchet would be easier but not necessary. Once the connector is removed, I have had trouble getting it off as evidenced by the spliced in connector.