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Intake manifold gasket change

Old 02-20-2010, 12:09 AM
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Default Intake manifold gasket change

ok guys. Im having some issues with my 01 SS. im hoping someone in here can help me out. As of lately my car began to have some issues. these included :
-Low oil light on, but oil level seems ok to me
-Smoke when rev coming from exhaust as well as by passenger side firewall
-Yellowish gunk on inside of oil cap
-NO overheating at all (not a problem, but worth mentioning since headgasket is a thought)
-Hesitation occasionally at low RPM but highway driving seems fine
-Occasional erratic idle, dips low but never stalls out

.. i kno all of these may not be linked together but i wanna make sure this car is driveable as i am pretty much dead in the water without a car. Speaking to some old guns of the car world, they all came to the conclusion that its the intake manifold gasket and not the headgasket.

So, basically what im asking for is your guys opinions on if i should start tackling this job? does it sound like intake manifold gasket? write up for changing this gasket? parts list?

I found a writeup on ls1howto for an intake swap so im thinking of following that.

sorry for the long post but im def jumping into this tomorrow morning and want to make sure im not going through all this for nothing

-adam
Old 02-20-2010, 12:14 AM
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one more thing. how much harder is it to do the head gasket than intake manifold gasket. IM thinking since im defintly ready to do the intake manifold gasket tomorrow, but u guys hypothetically might say its the headgasket, how much more involved am i looking to get or am i way in over my head?

-adam
Old 02-20-2010, 09:26 AM
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Can you be more specific on the smoke coming out of the exhaust - white, dark? Changing the head gasket is quite a bit of work. ls1howto has a writeup of it as well.

>>-Low oil light on, but oil level seems ok to me
There is a low oil sensor on the passenger side of the oil pan, basically a cork float and a switch. I would check the wires and connector going to it. If the oil level on the dipstick is good I wouldn't worry about it.

>>-Smoke when rev coming from exhaust as well as by passenger side firewall
Depends, could be bad or not. Smoke by the firewall could be an oil leak from your valve cover or a PCV line back there dripping onto the hot exhaust pipe/manifold. Could also check the oil pressure sending unit but that's on the back top driver's side of the motor, not the passenger side.

>>-Yellowish gunk on inside of oil cap
If you do short trips in cold weather you will get that gunk in the cap. Moisture in the oil that hasn't gotten hot enough to burn off. But if you change your oil and it looks like a milkshake that's a big problem.

>>-Hesitation occasionally at low RPM but highway driving seems fine
>>-Occasional erratic idle, dips low but never stalls out
These could also be from a PCV vacuum line leak. If you take the intake manifold off it's really easy to inspect all the vacuum hoses. Replace anything that looks cracked or worn. Look closely at the plastic vacuum line junction that links the valve covers in the back, that can crack.

Maybe also carefully clean the wires on the MAF.
Old 02-20-2010, 09:35 AM
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My two cents You didnt list the mileage of the car and thats important...but here is where I would start

-Low Oil light, but level is fine, Replace the sensor in the oil pan, Thats prolly the problem
-smoke when reving could be multiple things, from bad rings to valve seals, But you are isolating the pass side by the firwall so I would check for a bad valve cover gasket first,, Look on the heads and block for oil leakage, when oil gets on the heads and exhaust it smokes, if the smoke is coming out of the tailpipes then you are possibly facing the rings or seals.
-Yellowish gunk on inside of oil cap means moisture has gotten into the engine many different scenarios, change your oil and look for that in the oil, any milky look means moisture, generally a head gasket leaking coolant into the oil. If the oil looks fine, Just replace the cap and keep a close eye on it.
-If you really suspect a head gasket blown you can do a compression/ or leakdown test and look for a big difference, If the car is running fine, not overheating,and the oil looks fine I highly doubt you have a blown head gasket.
-the last two problems you list about the erratic idle and hesitation, The very first thing I would do is replace the fuel filter, if still doing it put a fuel pressure gauge on the rail and see what it is. If its low or erratic your pump may be giving up the ghost, If its fine it may be some dirty injectors or plugs starting to foul out.

the intake manifold leaking would cause a severe Vaccum leak and the car would not want to run at all, and the ecm would prolly send a ses light. Replacing the intake takes me about 40 minutes, I have done it more than a few times its not that bad at all, the intake has no gaskets it uses individual o ring seals, about 20 bucks at autozone. Take a can of starting fluid and spray it around the edges of the intake(where it sits against the heads) generally if there is a vacuum leak it will suck the starting fluid in and cause an increase in Idle RPMS a noticable increase. thats an easy way to check for an intake leak. If you tackle it the only special tool you will need is a disconnect tool for the fuel line (3/8). When you remove the back bolts you cant get them out of the car not enough room. I use rubber bands around the heads and fuel rail to hold them up during removal.
To answer your head gasket question it is a substancially bigger job than the intake. you will need to remove the intake some accesories, exhaust and such. then you will need new gaskets and bolts, the bolts are one time use only.. From what you described I would start with all my suggestions above, they are more than likely the problem and fairly cheap Hope this helps. Personally If your oil is clean I dont believe either of your head gaskets are blown, I also dont believe you have an intake leak, But I am not under the hood so this is just my advice. Hope it helps
Ronnie
Old 02-20-2010, 09:57 AM
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93,xxx miles.

thanks for the input guys. so now im thinkin im gonna pull the intake manifold and see whats goin on. check the valve covers and pcv and replace/tighten as necessary. sound good?

Last edited by TransAm619; 02-20-2010 at 10:32 AM.
Old 02-20-2010, 11:55 AM
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Originally Posted by TransAm619
93,xxx miles.

thanks for the input guys. so now im thinkin im gonna pull the intake manifold and see whats goin on. check the valve covers and pcv and replace/tighten as necessary. sound good?
its a start...
Old 06-09-2010, 05:43 AM
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You know i'm having the same issue on the exception of smoke coming from the exhaust. Only thing is I have no clue on fixing cars. I have white smoke coming inside my car when I excellerate. On top of issues "Hesitation occasionally at low RPM but highway driving seems fine."
"Occasional erratic idle, dips low but never stalls out"

And I don't know how to fix cars.
Old 06-09-2010, 07:21 AM
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I gotta tell you the LS1 is NOT a wet manifold...no coolant runs through it. Nothing to leak.
Old 06-09-2010, 07:48 AM
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moving to external.


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