Lower Intake Gasket Replacement
#13
Senior Member
True Car Nut
May I ask how many miles are on the car?
If over 60k, and the lower intake manifold gaskets are the old nylon 6,6 ones, then I'd highly suggest going ahead and changing them out with the aluminum ones, if you unsure if they are already aluminum you could test them with a DVOM.
When you remove those coolant elbows they typically break if they are old elbows, so I am not convinced that is your only possible leak.
If you already replaced the coolant elbow, and you used the Dorman Help ones, I'd recommend replacing those o-rings, see the thread below for info on problems with those failing, there are supposed to be elbows out that they fixed the o-ring problem, but I am not buying it, I will only use the ones that come with the Fel-Pro LIM Kit I recommend, or the AC Delco ones listed around the last page of that thread.
http://www.gmforum.com/showthread.ph...t+elbow&page=1
Make sure to clean those holes well where the elbow goes in, I used some steel wool myself, you want to ensure the bores are as clean as possible, or the new o rings can possibly fail.
Some suggest a little RTV on the o rings for the elbow, it never hurts, but I found if you use the right o-rings that is not really necessary.
It is only a matter of time before the nylon gaskets will fail, typically around the coolant ports, and also around the upper intake manifolds egr ports, that can be remedied with installing a reduced diameter EGR Stove Pipe, it comes with the Fel-PRO aluminum LIM Kit I recommend.
An even better remedy for that failing and leaking would be a new upper intake manifold from ineedparts, they sell one with a steel bushing to help the reduced egr stove pipe keep that area cooler.
You could put the bushing in yourself if your UIM is still good, but I find just replacing the EGR Stove Pipe enough to keep that area from ever leaking.
I recently did my LIM gaskets and found they were almost disintegrated, it was only a matter of time before I would have had a hydra-locked motor, which means you could possibly throw a connecting rod, or ruin bearings, which means you need to rebuild it, or get another motor swapped into it.
If you would like I could provide links for all the parts I suggest, I usually get most of them from rockauto, as they have good prices.
If over 60k, and the lower intake manifold gaskets are the old nylon 6,6 ones, then I'd highly suggest going ahead and changing them out with the aluminum ones, if you unsure if they are already aluminum you could test them with a DVOM.
When you remove those coolant elbows they typically break if they are old elbows, so I am not convinced that is your only possible leak.
If you already replaced the coolant elbow, and you used the Dorman Help ones, I'd recommend replacing those o-rings, see the thread below for info on problems with those failing, there are supposed to be elbows out that they fixed the o-ring problem, but I am not buying it, I will only use the ones that come with the Fel-Pro LIM Kit I recommend, or the AC Delco ones listed around the last page of that thread.
http://www.gmforum.com/showthread.ph...t+elbow&page=1
Make sure to clean those holes well where the elbow goes in, I used some steel wool myself, you want to ensure the bores are as clean as possible, or the new o rings can possibly fail.
Some suggest a little RTV on the o rings for the elbow, it never hurts, but I found if you use the right o-rings that is not really necessary.
It is only a matter of time before the nylon gaskets will fail, typically around the coolant ports, and also around the upper intake manifolds egr ports, that can be remedied with installing a reduced diameter EGR Stove Pipe, it comes with the Fel-PRO aluminum LIM Kit I recommend.
An even better remedy for that failing and leaking would be a new upper intake manifold from ineedparts, they sell one with a steel bushing to help the reduced egr stove pipe keep that area cooler.
You could put the bushing in yourself if your UIM is still good, but I find just replacing the EGR Stove Pipe enough to keep that area from ever leaking.
I recently did my LIM gaskets and found they were almost disintegrated, it was only a matter of time before I would have had a hydra-locked motor, which means you could possibly throw a connecting rod, or ruin bearings, which means you need to rebuild it, or get another motor swapped into it.
If you would like I could provide links for all the parts I suggest, I usually get most of them from rockauto, as they have good prices.
#14
Senior Member
True Car Nut
Wish I could edit...
When I said you could put the steel bushing in the UIM'* egr port yourself for extra heat protection, I forgot to mention it involves some JB Weld and a little grinding/sanding if I remember correctly, the ineedparts UIM costs a bit, but is less of a headache than doing it yourslef, I also forgot to mention you can block off the throttle body coolant ports as some do, but you may have hard starts when cold, and you will lose coolant flow, so you'd typically want to remove the coolant water bypass cover and bore that area inside out a bit to add some flow back.
I wish I knew more and could explain better, but I am still learning a bit, I am getting to know the 3800 Series II fairly well, and hope to learn all that I do not know yet, which is why I am here.
When I said you could put the steel bushing in the UIM'* egr port yourself for extra heat protection, I forgot to mention it involves some JB Weld and a little grinding/sanding if I remember correctly, the ineedparts UIM costs a bit, but is less of a headache than doing it yourslef, I also forgot to mention you can block off the throttle body coolant ports as some do, but you may have hard starts when cold, and you will lose coolant flow, so you'd typically want to remove the coolant water bypass cover and bore that area inside out a bit to add some flow back.
I wish I knew more and could explain better, but I am still learning a bit, I am getting to know the 3800 Series II fairly well, and hope to learn all that I do not know yet, which is why I am here.
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