2000 Buick Century Intake Gaskets FUBAR

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JimmyJohns

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Hello gentlemen, it's been a long weekend.

Yesterday we brought in my mothers 2000 Buick Century with the 3100 motor to do lower and upper intake gaskets. Used a full Felpro kit, got her all buttoned up and started her up and theres a knock. We took off the rear valve cover, which was dry, and cranked but there was no oil. Front we did the same and that had oil. Took off the upper intake and it was cracked, went out and bought a new one, installed, started, still that same knocking, sounded like lifters.

Pull it all apart, and pull off the lower intake, and thats cracked in the center, theres indentations from the center of the gasket that looks like it was malformed and caused it to crack, also looked like it caused a push rod to rub on the intake.

Today we went to the junkyard to grab a lower and upper intake, put it all back together with a new set of Dorman gaksets, start her up and same noise, except this time, no oil in the front valve cover either.

What in the schnikes happened, simple intake gasket job just went awry, anyone have any suggestions of what to do? My mechanic is going to test for oil pressure tomorrow, but I just don't understand how we lost oil pressure in the top end from doing intake gaskets. Changed the oil both times it was all buttoned up after pulling the lower intake. Heres an album with some pictures, I'm very curious if anyone has an explanation or has heard of this happening because all of us are scratching our heads.

http://imgur.com/a/dpjkz
 
Did you note that the intake gaskets have small tabs that have to seat in small holes in the head-intake mating surface for everything to button up correctly? Also, oil supply to the head is picked up by the lifters in the valley and pumped up through the hollow centers of the pushrods past the rocker arms. Seems strange you only had oil on one side...
 
I'm not sure about the oil issues, but I thought Fel Pro was the one with the corrected design?
 
It is indeed very strange, and just to note, I wasn't the only one doing the job. My friend is a mechanic with his own shop who has done these countless times, which is not to say mistakes can't be made I suppose. But yes, the gaskets themselves were installed properly both times, I'm not sure if you are able to see that via the pictures.
 
The corrected design I believe is a metal core rather than plastic, which Fel Pro indeed is. Dorman, and Mahle also make updated intake gaskets. The big issue with the plastic gaskets I do believe is that Dexcool has a reaction with them and they deteriorate.
 
Originally Posted By: Trav
Did you get some of the long and short push rods mixed up?
You are truly the master!!!
 
No we didn't, punched 12 holes in a box, 6 in one row, 6 in another, marked front and back of motor, and proper orientation left to right(the order we took them out). The pushrods were not mixed up, that is a sure thing, good suggestion though.
 
Did debris get into the lifters during the repair? Were the pushrods throughly washed in solvent and blown out with compressed air? (They looked a little grimy to me in the photos). Are the rocker arm oil holes clear of debris or sludge?

Were the lower intake bolts and bolt holes cleaned, thread lock applied and torqued to the proper inch pounds and in sequence? Mistakes here could have caused the cracked manifold or leaks later on. Were the gasket locating tab holes clear?

Did the oil filter get replaced in the oil change? If so, was it filled with oil prior to install?
 
I would test the lifters, are they somehow collapsed on one side?

Engine sound like a rattle can of spray paint?
Is everything clean? Sludge? Blockage? Oil pick-up?
Were the parts from the same year? 2000 was a mild redesign on Centurys.

There has to be SOMETHING making the 3100 only get oil delivered to one side. That is not normal.
 
Originally Posted By: JimmyJohns
It is indeed very strange, and just to note, I wasn't the only one doing the job. My friend is a mechanic with his own shop who has done these countless times, which is not to say mistakes can't be made I suppose. But yes, the gaskets themselves were installed properly both times, I'm not sure if you are able to see that via the pictures.


For clarification- The second time you put it together, it went more or less as can be expected?

I'm thinking that maybe one the locating dowels (I believe there is one at the upper part of the center port) may have popped out of the hole in the head (or the hole in the head was full of debris) which caused the gasket to raise up and ultimately lead to the cracking of the lower intake.

As for the oil pressure, did you by chance happen to remove the dummy distributor shaft to replace the leaky o-ring? That also drives the oil pump.



Originally Posted By: JimmyJohns
The corrected design I believe is a metal core rather than plastic, which Fel Pro indeed is. Dorman, and Mahle also make updated intake gaskets. The big issue with the plastic gaskets I do believe is that Dexcool has a reaction with them and they deteriorate.



Contrary to popular belief and all the DexCool haters, it was not an interaction with the coolant that caused them to fail. It was just stupid place to put a plastic gasket! I've seen the plastic gaskets that were installed pre 95 or 96 (whatever Dex's first year was) look just as terrible. Further if the material (PA66) and Dex didn't play well then there would be tons of radiator tanks failing left and right- because they are made out of PA66 too, as are t-stat housings, coolant nipples, and so on.
 
I just looked at your pictures, are you sure those gaskets are not on backwards or are they side specific? Its been years since I did one but something looks wrong with those pushrods to me.
Try installing the lower intake with the pushrods out, make sure the short ones are going to intake and long to exhaust. I looks to me like the lower manifold got damaged from hitting a pushrod. I have no idea but that's what I would be looking at.
Just go through it and double check everything, that's all you can do.
 
Trav they aren't side specific and they appear to be installed correctly, though I would have liked to have seen the cylinder head and cylinder head side of the gasket too.
 
Indeed in the pic they look suspiciously close. My way thinking is that if the pushrod got in the way it'd have been really obvious when the intake was installed- that thing would have been a teeter totter and there also should have been a witness mark. I do see a mark on the side of the port, but that's towards the bottom and I don't think it would have caused the break up top.

I'm focusing on the witness mark on the center of the port where the break is- I think that the gasket was held up a little somehow which caused the lip of the intake port to crack. But if that were the case there should have been a corresponding mark on the head- and we don't have any pics of that.

It will be interesting to hear what the o/p has to say in regards to whether the second lower intake and Dorman gaskets went on okay. It would also be nice to hear what he has to say about the possibilities brought up by everyone so far.
 
I was there with JimmyJohns and our friend mechanic.

Originally Posted By: zzyzzx
Did you remove the rocker arms or use the pushrod tool?


Loosened the rocker arms.

Very strange why when the car came in, it had oil to the heads. After, nothing.

The pushrods were clean inside. I find it super hard to believe that no oil whatsoever would travel through them if there were debris in the lifters. At the very least, not all twelve... I'm sure we would've seen something.

Filter was replaced second time around, pre-filled by yours truly with some 5W-30 Supertech.
 
All of the valves were moving real nice, up and down. Cranked it with the VCs off to look.
 
Idiot light for oil pressure never lit. Bottom end sounds like its getting lubrication.
 
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