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Oil filter adaptor gasket replacement 8th gen 3500/3900

91K views 30 replies 20 participants last post by  Danny09police 
#1 ·
One of the most common oil leaks on the 8th gen v6 is the oil filter adaptor, if underneath your car looks like this
and you have a drip from the filter while the car is running, that's your issue. The part is very inexpensive from the dealer, here is old vs new with the adaptor on the right


To do this job, you will need a jack, jack stands, 13mm and 15mm deep sockets, , 10mm socket, a ratchet, a screwdriver, 3" and 6" extensions, a universal joint, a drainpan, a lugwrench, and a serpentine belt tool if you have one, otherwise you can use a ratchet.


First remove the two 10mm nuts holding the coolant reservoir at the top and move it out of the way, then loosen the belt by turning the tensioner towards the front of the vehicle and sliding the belt off of the power steering pulley.


Next raise and support the front of the vehicle, remove the passenger front wheel. Loosen the lugs before raising if you don't have airtools.


Remove the splash shield, there are 3 clips holding it in place, unscrew the little Philips screw in the center and they will pull out, just push them in when you put them back.


Next remove the nut and bolt holding the AC compressor, shown top (nut) and bottom (bolt) using the 15mm socket


Now get under the car, place the drainpan underneath the filter, and remove the filter. Let it stop dripping, may take a few minutes, but it's better than oil running down your arms. Reach up and unplug the oil pressure sensor attached to the housing. Now look up by the compressor and you will see one more bolt holding it in place, also 15mm


Loosen this bolt, no need to remove it. Now slide the compressor towards the passenger side, it only needs to move a little.


Now you can access the bolt on the side of the housing, there are 3 in total holding it in place. Use the extensions and universal joint with the 13mm socket here. It works best to go in from the front of the subframe, just pull the plastic shield down and you'll have room


Remove the adaptor once all 3 bolts are out, remove the old gasket. Getting the new one to stay put is a little tricky, but you'll notice one of the bolt holes is slotted, start that bolt a few threads first and it will help keep things aligned as you get it in there. I don't use any particular torque spec here, just tight. I would recommend a new oil filter, but you can put the old one back if you want, it won't hurt. Move the compressor back in place and tighten the nut and bolt on the side first to ensure alignment before you tighten the one underneath. Everything else is the reverse of the above steps. Once it's put back together start the vehicle and double check for leaks, shut it down and check and top off the oil, you will have lost between 1/2 and 1 quart. That's it! This process took me 1 hour while stopping to wipe my hands and snap pics, give yourself 2 hours to be safe.
 
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#2 · (Edited)
Gotta get under mine today and do an oil change.
It's a 3.9 and I thought that the filter/adapter etc was a bit further way from the compressor, but will look closer at it for sure.

Why do they fail ? OE gasket a POS, or do they come loose ?

EDIT:
Got under it yesterday and looks exactly the same as the 3.5.
It would be a pita to do I think with my big hands and lack of mobility, but I looked at what you spoke of once under there and it made more sense.
You have probably got it down to 90 minutes by now.
 
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#3 ·
The gasket fails, it stays nice and tight. I'm 6'2" and wear xl gloves, if I can do it so can you! Actually it took an hour, even stopping for pics. The first couple times took me about 2 hours, but a lot of that was trying to figure out what I needed to do. Moving the compressor is quick, and solves most all of the problems.
 
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#4 ·
Is this one of those

"IF IT FAILS" or

"WHEN IT FAILS" type of things.

And !

Why does it fail ? Is the OE gasket a POS or is it because the bolts back out.
Just wondering if I should check the bolts each oil change.
 
#5 ·
The bolts are always tight when I do the replacement, so I don't think thats the issue. The gasket just has a lifespan that gets exceeded.
 
#6 ·
I just did this gasket today, wish I seen this write up before I did mine very helpful, I pretty much did the same thing except I removed the front two cradle bolts and slowly lowered front cradle to give myself some more room, but I think this a common problem on these. Mine started dripping oil so it was time!


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#8 ·
Really good write up ! But on my 07 I ran into a couple of issues. First off my car has an oil cooler and trans cooler. Both those lines ran directly in front of the already pita compressor bolt under the car. Took me forever just to figure that situation out. Now that I got the compressor moved I took the bolt from the side of the housing out pretty easily. But I can't even seem to figure out where the other two are
 
#9 ·
::::update:::: i got mine on fine but i had an extra step than you. i had to take out the driver side oil cooler line going into the adapter housing so i could get the third bolt {the one thats 3 or so inches long} i got everything back together plugged in the sending unit and took it for test. it ran fine. later that day i pulled it out of the driveway in reverse then put it into drive and the very millisecond i stepped on the accelerator i get a reduce engine power warning and the impala started shaking. it wouldnt move at all basically. i shut it down and cycled the engine 3 times. it went back to normal but now its pulling a code.... this cant be the response of a new gasket. also this is the first time ever i pulled the - battery on this car since i had it and it reset the system. gonna try to get a code today any thoughts??
 
#10 ·
be good to know what the code is but in the mean time, if you want, disconnect the battery for a couple minutes and hook it back up again. .
This will however erase the code it has stored, but, if there is still a fault in the system it will return.
 
#15 ·
hello,

First thank you so much for this write up. I have never worked on cars but with this write up I was able to complete this repair.

i did have a follow up question. the gasket I got from autozone does not look like the one in your photo, is that just a difference is supplier?

after getting the car back together it is still leaking from the same spot only worse, do you think this is because the oil filter housing needs the bolts tightened.

thanks again for the write up.
 
#16 ·
thanks for the post and its attention to detail, it is super helpful. Just an alternate method, I found out taking off the splashguard completely gave me enough room with my hands to take all 3 bolts off so I didn't have to touch the compressor. saves you taking the wheel off but you have to mess around with more of those stupid plastic clips
 
#21 ·
I think he may have meant head gasket
 
#27 ·
I need to check mine. My cars been dripping oil. I took it to get the oil changed instead of doing it myself back around November and they said the oil pan gasket was bad that's why it was dripping. Bought the gasket like two months ago just haven't had time to change it. I'll be sure to check this as well.


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#28 ·
An alternate method

I have done a couple of these, did one this morning, but I found it easier to remove the exhaust manifold. It comes out without too much trouble and then you have a wide open shot to the oil filter base. To remove the manifold, 1st remove both heat shields covering the manifold and the crossover pipe, loosen the heater hose tubes below the throttle body to get room to remove the heat shield. Also remove the torque strut closest to the front of the engine, along with the vertical bracket it attaches to. You can now unbolt and remove the manifold and have easy access to the oil filter base.
If you want even more room, take the radiator fan out also!
 
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