 |
 |
|
|
|
|
This page is dedicated to fixing one of the most expensive and odious problems that the 3.4 suffers from, the dreaded oil pump drive O-ring oil leak. Some of you will be lucky and never see how bad this is, but the rest of you who have been afflicted (like I have, 2 quarts per week) with the dreaded o-ring leak will thank me for describing how to fix this for under $950.00 (what the dealer charges). You must remove the upper and lower intake manifolds to accomplish this task, but contrary to what the factory manual states, you do not have to remove the fuel rail or the rear cylinder head. I just performed this operation myself, so I can tell you that not only is it possible, but it does work just as described here. This is fact, not somebody's "well, I think you can do this and it might work". If you do this all yourself, the parts are going to cost around $200.00-250.00, to do it right. This is what you do:
0 Relieve the pressure in the fuel system.
This site created on 20 December, 2002.
0 Remove the air box and IAT sensor connector, and place aside.
0 Remove the negative battery terminal.
0 Disconnect the upper radiator hose at the thermostat housing.
0 Disconnect the coolant transfer "L" pipe next to the thermostat outlet. It comes out by squeezing the push tabs on the sides.
0 Nut on the thermostat housing that holds the cross-engine coolant transfer pipe in place.
0 Disconnect the IAC, MAP and TPS sensor connectors and lay the harness aside.
0 Remove the two retaining bolts and disconnect the EGR valve and wiring and remove. Leave the EGR down tube in place.
0 Remove the throttle and cruise control cables from the throttle body crank by sliding the metal end out of the crank groove. There aren't any retaining clips, they just stay in by spring pressure pullling the crank back to the rest (idle) position.
0 Disconnect all the little spaghetti lines that carry vacuum to various places.
0 Remove the plastic valley cover w/ the "DOHC" logo on it.
0 Remove all the upper manifold hold-down bolts and set them aside.
0 Remove the manifold hold-down nuts located on the back of the intake manifold. (Not very easy to see, but there are two of them just below the PCV transfer hoses.)
0 Disconnect the heated throttle body coolant transfer hose underneath the plenum (not easy). (You may want to try this before removing the manifold bolts.)
0 Lift the manifold up slightly w/ a 1x3 board and slip a socket under the throttle body to remove the single fuel rail bracket bolt (10 mm, I believe). Use a stubby socket and a thin head ratchet for this. It's not easy, but it can be done.
0 Slide the manifold forward and disconnect the vacuum hose that runs to the power brake booster. This should probably be replaced at this time as it rots out quickly from severe engine heat and is quite difficult to change w/ the intake in place.
0 Flip the manifold upside-down and remove the throttle/cruise cable retaining bracket from the bottom of the throttle body.
At this point, if you've done everything right and I haven't missed any steps, the manifold should lift right off and out. You will get a little coolant spillage as there is an o-ring between the upper and lower manifolds that heats the throttle body. Be sure to remove this as you will replace the o-ring later.
Now, onward we go.
0 Remove the fuel injector electrical connector clips carefully and set them aside. Be sure that the little square water seals inside the connectors don't drop out and get lost. Three of mine fell out.
0 Disconnect the ECT sensor electrical connector.
0 Remove the four fuel rail hold-down bolts and carefully set the rail off to the side (toward the front of the car). Don't bend the fuel pipes too far as they are made out of nylon and may crack or kink. You will probably have to pry the rail out of the manifold carefully w/ the handly dandy 1x3 from the step above. Just a small amount of pressure should pop it free. The injector o-rings get welded to the aluminum from heat and age.
0 Remove all the lower intake manifold hold-down bolts and remove the manifold. Four of the bolts are on the lower ends and are almost impossible to see, so don't fight w/ the manifold if it doesn't want to move. If its stuck, you probably missed a bolt. The forward one under the thermostat housing (front cylinder bank) is the most miserable as it is almost invisible.
Here we are, now you can see your nemesis.
0 cover all openings into the cylinder heads w/ shop towels so no grindings or dirt get into the intakes or coolant passages.
0 Using a Dremel-type rotary tool or equivalent, cut off the lower half of the threaded boss that hangs down over the oil pump drive. Be careful NOT to cut too deeply into the threads that are inside the boss. Just graze them a little.
0 Remove the oil pump drive V-clamp hold-down bolt and pull the pump drive up slightly. It will hit the cylinder head boss but it will be enough. Clean as well as possible all oil and junk residue from around and under the pump drive.
Using RTV red or equivalent (600 degree rated), lay a bead as well as possible all the way around the inside of the pump drive. Push the drive back into the engine until the RTV is slightly compressed and rotate the drive several full turns. This will drag the RTV around the inside and hopefully distribute it somewhat close to evenly. Obtain a Buna-N O-ring about 1" ID and slide it onto and then under the pump drive before the RTV sets up. (This will happen fairly quickly. I had to pry the drive back up to get the O-ring in because the RTV red had already started setting up.)
0 Install and tighten the pump drive V-clamp hold-down bolt. Don't get crazy w/ the torque, just squash the O-ring sufficiently. Between the RTV and the O-ring, you shouldn't have any more oil seepage. The stock O-ring remains inside the engine and between the two, should keep the oil inside.
Installation is mostly the reverse of disassembly, but heed the following:
0 Don't even think about using any of the old parts over again. They are going to be junk from age and heat baking. These are all parts that can NOT be replaced at any other time without ripping all this stuff off again. At the minimum, replace the following w/ GMC/Goodwrench or aftermarket equivalents:
1. Upper and lower intake gasket kit w/ intake manifold coolant transfer O-ring (located just under the throttle body).
2. ECT sensor, it gets baked by ungodly heat under the lower intake manifold and the plastic body of the sensor itself may break when you try to remove the sensor electrical connector (mine did).
3. The entire PCV vacuum hose kit including the "S" shaped flexible hose that connects to the oil gallery tray (right behind the power steering pump, under the lower intake) (Mine was so heat baked that the inside of the flex hose had turned to a composition resembling bakelite and shattered as I tried to remove it).
4. Vacuum hose assembly from the fuel pressure regulator to the intake manifold vacuum manifold (right under the MAP sensor) (If this rots out or snaps you don't get any fuel pressure higher than base idle (45 PSI) and will not get maximum horsepower; and can risk engine damage from running lean at WOT).
5. TPS if your engine has more than 50K miles on it. It's much easier to do it now. It can be done later but the IAC is in the way.
6. Heated throttle body coolant transfer hose. (You probably destroyed it getting it off anyway).
7. Fuel injector tip seal O-rings. They will be heat rotted and the factory replacements are now an upgraded blue material. This is a running change service kit issued by Goodwrench. The bag has like 50 of them in it (A slight exaggeration but there are more than plenty to replace the upper and lower rings and still have some spares. Not sure why they give you so many.) Lube them with clean motor oil before pushing the injector/rail assembly back down into place.
8. Power brake booster vacuum hose, if rotted or heat dried (hard and brittle).
9. 180 degree HyperTech thermostat. Why not, you've already got the stat housing out anyway, gain some performance at the same time. The stat is O-ringed too, so no messing with gaskets or goop, only two bolts. Very cool.
10. RSM Motorsports oversize upper intake or Extrude Hone?!!! This one's your decision. 15 to 25 HP, from what I hear but pricey. ($199 RSM, $700+ for Extrude Hone upper & lower).
To get the throttle and cruise cables back in place, place a rolled up piece of cardboard or a small block of wood inside the throttle opening under the throttle plate to hold it partially open. It will be almost impossible to complete this operation w/ the throttle plate completely closed.
The lower intake is wierd. There are rubber/plastic composite rings around all the intake bolts and the intake gaskets are plastic composites w/ integral O-ring type seals cast on. I've never seen anything like these, but they are great (no gasket scraping). However,:
Install the four lower end intake hold-down bolts (the invisible ones), then set the intake back on the engine. You will never get them back into their caves after the intake is on the motor.
To seat the lower intake correctly, you MUST obtain two bolts about 1-1/4" - 1-1/2" long that fit the metric threads in the cylinder heads. There are two bosses that sit flat in the valley of the intake for this purpose. Most likely, they were empty when you removed the intake. You will NEVER get the intake on straight and avoid SEVERE cylinder head damage from cross-threading if you don't do this. You will have to jack the intake around very slowly, a quarter to half turn at a time until the strange rings that hold the intake bolts in place line up properly. When everything aligns correctly, you will be able to tighten the retaining bolts most of the way in by hand pressure only. DO NOT FORCE THEM. Back up if they won't go in and do it again. ABSOLUTELY DO NOT DRIVE them in. This part is tricky and time consuming, so don't be in a hurry and if you're already tired come back and do it later. This is absolutely the one part that CAN NOT be rushed. Leave the alignment bolts in place. At this point, they have no further purpose and you might need them later. They will just ride around w/ the car.
The lower intake manifold bolts MUST be tightened to 18-22 LB/FT in a criss-cross pattern starting at the middle. Work up to this torque in two steps.
Be sure to remember to open the coolant bleeders when refilling the cooling system, or SEVERE cylinder head damage will result from air locking.
Go slow and think everything through. There may be a few small things that I missed here, so use some intelligence and less force and the project should work out without any permanent damage to yourself or any of the car parts. Keep in mind that this information is provided for educational purposes only, and Midtek Industries does not warrant that this information is complete or 100% factual. Apply this knowledge at your own risk, and always put safety above every other priority.
We have had
visits since 13 September, 2002.
© 1996-2003, by Midtek Industries. This site created by Midtek Industries, who is solely responsible for its content. No portion of any information presented here may be reproduced or stored in any paper or electronic form without prior express written permission. The General Motors logo, names 'Pontiac, Grand Prix, Oldsmobile, Cutlass Supreme, Chevrolet, Lumina Z34, GNX, Syclone, Typhoon and Trans Am' and all other badges, insignias and indicia are the copyright and trademark properties of the General Motors Corporation. 'Harley' and 'Harley-Davidson' are all trademarks of the Harley-Davidson Corporation. 'Sledgehammer' original score by Peter Gabriel.
All other corporate and trade names mentioned in this site are copyright and trademark protected and licensed by their individual corporations. No affiliations or endorsements by any other corporations are expressed or implied by Midtek Industries. All information contained herein is correct to the best of our knowledge, but as verification of sources can be difficult, we assume no responsibilities for erroneous information.
All 3.4L line art represented here is courtesy of General Motors Corporation and Helm Publications. This art is reproduced here only in the interests of education.
This page was created with the Hot Dog Pro Web Page Editor
Go There!!! Check the current prices on used W's at Kelly Blue Book.com, the webs largest and oldest automotive valuation company.
Go There!!! Order the factory repair manual for your exact year and model from Helm Publications. This is the company that actually publishes the repair manuals under contract for General Motors, and these are the exact books you will see in the GM dealership service bays. They aren't cheap, but they're the best. Trust us, the owner of the company used to do work for them.