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No oil pressure!


divemaster
05-01-2005, 11:48 AM
Hey all!

I just changed head gaskets - lots of oil pressure before but now I have none..

If I take of the oil filter and start the engine - nothing comes out!!! I had a buddy change the oil pump drive shaft o-ring - he said it went fine.... Any way to screw this up???

engine: 3.4 V6
Veh: 1998 Trans Sport

HELP!!!!!!!

LMP
05-01-2005, 11:57 AM
I do not have the specific details for the 3.4 but...this one has no distributor..so I figure the shaft that drive the pump is the same one that normally supports the distributor, except it is probably stubbed just above the gear....and there must be some device that keeps it in place so it does not move up and escape camshaft under screw gear action...So, is it possible that some locking device was left missing and the gear is not in contact with the cam?.....I do not like the idea of removing the intake manifold again for checking this, but I remember a post mentioning there is a cap in this area covering the place where the distributor would normally be....would it be possible to use that orifice to have a glance at the situation under?....I remember you have a borescope....

divemaster
05-01-2005, 12:00 PM
Hey! Glad you are here! There is a cap - I may have to take off the upper intake manifold to get at it but then again I may not.... my buddy said the shaft slid in no problem so I did not even question it..

Do you think I can get away with using the same upper intake gasket again?? Has not gotten hot yet and has only been torqued on for 1 day....

Shane

LMP
05-01-2005, 01:11 PM
My perception is this gasket is not critical to the point it cannot support being reused, specially since it is brand new and will probably not tear apart on removal. There are no components under pressure either..except vacuum . TO me it is a "on condition" item.
I fully agree that the shaft might have "slid in" easily....the problem is I hope it does not slid out the same way....well in fact, if it was that, then too bad it happened, but it would be probably corrected easily..I just wish the lower part of the manifold does not need to be removed......

divemaster
05-01-2005, 02:08 PM
the lower manifold has to be removed too??

What did you meanby "the problem is I hope it does not slid out the same way....well in fact, if it was that, then too bad it happened, but it would be probably corrected easily"??

Thanks for getting back.

LMP
05-01-2005, 04:05 PM
I read your comment in previous post like meaning the oil pump driver shaft had been removed (for the o-ring ) and then put back in easily...so I was thinking if there is nothing to keep it in, like some retainer taht would have been forgotten, it might as easily get out...may be I"m totally out of the track.....I was just figuring out the way it could possibly be.....sorry if I confused you, I was just speculating. And indeed, looking at the diagrams I have here for the 3.1 (the 3.4 is very ressembling) I see no reason why this problem..which has yet to be identified...would not be solved with the upper half removed.
My 3.8 is totally different..the oil pump is on the front of the engine on the crankshaft.

divemaster
05-01-2005, 04:32 PM
cool!! Thanks - I was sweating!!

This is (as you know) one of those jobs that when you are done, you want to turn the key and have the engine roar into life and run smoothly - and when it does not - your heart sinks!!!

I don't know about any retainers inside - the Haynes manual that I have does not really say much about anything.. I am researching online.

It just seems to me that if it went back in with no problems then it should work! I would hate to tear back into it again to find that is not the problem...

LMP
05-01-2005, 06:18 PM
The oil pan was not removed and the oil pump was not emptied so there is no reason it would not deliver oil if it did rotate.....there were allegations in another post - not sure what engine it was - that when the pump is totally emptied, there may be some problem priming it but I'm a little skeptic about that and anyway, I'm convinced it does not apply here. I'd want to be sure the stub shaft does rotate with the camshaft and that it is indeed connected to the pump under it. Why woudn't it be connected, I just wonder.....
In fact, how do you describe the shaft that was removed to change the o-ring? How does that picture
www.avigex.ca/xport/oilpump31.jpg make sense with what you have dismantled?

divemaster
05-01-2005, 07:01 PM
Thanks for staying with me! (and taking the time to find and upload the picture.)

The picture only seems to show one gear - which is what my buddy described.. If this is the case - how does it drive the pump??
The picture is accurate - just not detailed enough.
I have an old 3.1 that I am going out to my shop right now to pull the shaft out of and see what it looks like - I will get back to update this post later this evening.
Any other suggestions??

Thanks! - Shane

LMP
05-01-2005, 07:20 PM
In fact the camshaft itself has also a gear -not shown - that drives the gear you see on the pump shaft.
NO I do ot see anything else, even the hypothesis we evocate looks hairy.....but it seems this is all we have.....how long did the engine run before this lack of pressure was revealed?

cdru
05-01-2005, 07:38 PM
The drive shaft for the oil pump should be able to be gotten to with just removing the throttle body from the upper intake manifold. You shouldn't have to remove either intake manifold.

You can see the top of the drive shaft under the TB. It's looks like a cap that's silverish in color and is held in place by a steel "Y" shaped bracket that just holds it down. There is a single bolt that holds it down. If the silver "cap" is touching the top of the block, it's down as far as it will go. It doesn't get recessed.

The silver cap is more or less directly connected to the gear that turns the shaft. A square drive shaft then goes down into the oil pump. I beleive it's a fairly straight shot, but it might be possible for it to go sideways and not fit into the opening for the oil pump. It's been a while since I did mine, so I don't remember what it looked like when peering down. I do remember the drive shaft having a tendency to fall out of the drive portion so I had to put a little sticky grease on the shaft to hold in in while lowering everything and snapping it into place.

I would start by popping off the TB and pulling out that drive shaft again. Either it's missing, or not installed correctly. Anything more then that, and you probably have much more serious problem somewhere.

Afterthough: Does the car start? That would at least indicate that the camshaft is spinning and that it's not broken or the timing chain snapped...

divemaster
05-02-2005, 08:27 PM
Thanks for the posts!

The engine did start. I have an old 3.1 sitting on the floor of my shop which I took apart to have a look at the system.
it does not look possible for the drive unit to be installed wrong.. however, you never know until you look.
Thanks for the advice - I will take off the TB and have a look. I will also try driving the pump with a drill to see if I can make a mess of my shop floor with the filter off - if this works - that kinda sums it up!!

Shane

divemaster
05-20-2006, 08:40 AM
believe it or not it has been about a year.. I am sorry for not updating the post - but I was very frustrated.

If it helps anyone - the cam shaft was broken in half. I pulled the heads and got the cam shaft out - but the two center bearings had spun soooo bad that the journals were toast. I closed the garage and left the van until last weekend. $1000.00 cdn from the auto wreckers and this weekend I will be changing the engine..

By the way - I was easily able to remove the engine/trans without a hoist...

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