Intake manifold gaskets
#21
12-23-2006, 07:41 PM
RE: Intake manifold gaskets
ORIGINAL: swartlkk
swdockter, you really can't pin it down to a leaky intake manifold gasket right off the bat. I would suggest you do a coolant flush and refill, changing out the t-stat and the radiator cap (both very cheap items). You should also check the weep hole on the bottom of the water pump for signs of seal leakage. If there is dampness on the crank pulley or lower, then you are probably looking at replacing the waterpump not too far down the road.
As for your temperature hunting around like that, you may have air in your system. If you do, it needs to be removed and fast. Dexcool is a great coolant, but it doesn't coat the internal passages like the ethylene glycol (green stuff) does. As a result, air that may become trapped in the system is allowed to oxidize the metal it is in contact with, creating the sludge that has given Dexcool its bad rep. I have found that the new Prestone All Makes, All Models extended life antifreeze ('big yellow') to be excellent and with the same extended life properties of Dexcool, without the down side of air issues, it is a no-brainer.
swdockter, you really can't pin it down to a leaky intake manifold gasket right off the bat. I would suggest you do a coolant flush and refill, changing out the t-stat and the radiator cap (both very cheap items). You should also check the weep hole on the bottom of the water pump for signs of seal leakage. If there is dampness on the crank pulley or lower, then you are probably looking at replacing the waterpump not too far down the road.
As for your temperature hunting around like that, you may have air in your system. If you do, it needs to be removed and fast. Dexcool is a great coolant, but it doesn't coat the internal passages like the ethylene glycol (green stuff) does. As a result, air that may become trapped in the system is allowed to oxidize the metal it is in contact with, creating the sludge that has given Dexcool its bad rep. I have found that the new Prestone All Makes, All Models extended life antifreeze ('big yellow') to be excellent and with the same extended life properties of Dexcool, without the down side of air issues, it is a no-brainer.
I now get gurgling in the heater core. I assume Ihave air and it should take some time to remedy itself. I'll keep an eye on the level and keep it full.
As far as any wetness anywhere...I only seen a small amount in the valley just under the intake. Not a lot but it sure doesn't give me any warm and fuzzies. I recently degreased the engine bay so everything is pretty clean andthe tiny little puddle was pretty visible. I sprayed carb cleaner on the area and I'm going to keep an eye on it and see if it reappears.
Thanks for all the help, this site is becoming one of my favorites.
#25
12-24-2006, 01:47 PM
RE: Intake manifold gaskets
Been searching around, there is a how to write up with pix at automotiveforums.com. Looks like you need a foot pound torque wrench, and an inch pound one. It looks like they were using RTV on the front and back of the manifold where it meets the block.I though i remembered my older chevys having rubber gaskets there. I keep going back and forth on whether I should do this myself or not.I worry about getting stuck and leaving the vehicle disabled. My Monte Carlo is not registered at the moment, so we would be without a car. This could be a good excuse to buy some tools 
.
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#26
12-24-2006, 02:59 PM
RE: Intake manifold gaskets
This could be a good excuse to buy some tools .
^^^^^^
You need an excuse to buy tools? You must be married.
One of the best modern day tools is a digital camera. A white paint pen is also a good idea. Just mark the position of the distributor etc.. and take a picture before you remove things. You can also use labelled bags for things like coil mounting bolts, distributor hold down, mainifold bolts etc... if you take your time and labell everything, it makes life easier.
. ^^^^^^
You need an excuse to buy tools? You must be married.
One of the best modern day tools is a digital camera. A white paint pen is also a good idea. Just mark the position of the distributor etc.. and take a picture before you remove things. You can also use labelled bags for things like coil mounting bolts, distributor hold down, mainifold bolts etc... if you take your time and labell everything, it makes life easier.
#27
12-24-2006, 04:51 PM
RE: Intake manifold gaskets
Correct, on the older engines GM did use a rubber gasket in the front and back seal. However they were known to leak. A nice bead of RTV is the preferred method.
Check those torque numbers, I could swear mine where in foot pounds. Also realize that one of the rear lower intake bolts has a higher torque then the rest.
As for best gasket. I prefer Felpro...
Here is a pic of my lower intake mainfold gasket. Notice the RTV on both the front and rear sealing surface. You need to put RTV around the water passages , and under the tab on the end of the gasket (where it meets the front and rear seal). Do that and you will have a good seal. One other thing, GM blocks off the rear water passage either on the intake. Some gaskets come with it blocked off and some dont. This one isn't. REgardless you need to put RTV around it as well.
Here is a closer pic of the area thats most important. See the RTV around the water passage, under the tab, and along the front seal?
Check those torque numbers, I could swear mine where in foot pounds. Also realize that one of the rear lower intake bolts has a higher torque then the rest.
As for best gasket. I prefer Felpro...
Here is a pic of my lower intake mainfold gasket. Notice the RTV on both the front and rear sealing surface. You need to put RTV around the water passages , and under the tab on the end of the gasket (where it meets the front and rear seal). Do that and you will have a good seal. One other thing, GM blocks off the rear water passage either on the intake. Some gaskets come with it blocked off and some dont. This one isn't. REgardless you need to put RTV around it as well.
Here is a closer pic of the area thats most important. See the RTV around the water passage, under the tab, and along the front seal?
#28
12-24-2006, 05:01 PM
RE: Intake manifold gaskets
Lower Intake Manifold Bolt[*]First Pass in Sequence
3N·m
27lbin[*]Second Pass in Sequence
12N·m
106lbin[*]Final Pass in Sequence
15N·m
11lbft
Upper Intake Manifold Stud[*]First Pass
5N·m
44lbin[*]Final Pass
9N·m
80lbin
#29
12-25-2006, 03:04 PM
RE: Intake manifold gaskets
The Victor gasket set I got from NAPAincluded a packet of the gray RTV sealant. I didn't get the whole set, just the lower intake ones for around $16. I removed the whole intake as an assembly as there is no need to take everything apart to replace just the lower gaskets.
The only torque wrech I used was an inch pound one. I also found that to get the lower power steering pump bracket bolts out (to move the pump and bracket forward for clearance) was to take the lower section of the air box out. I could then get those bolts out from the top alot easier than from below. I also cut the heads off a few bolts thatI had that treaded in where the manifold bolts go to use as guides for putting the manifold back on.
The fuel pressure and return lines at the back of the manifold are, or at least on mine, 5/8", not metric. My flare nut wrench was too long and hitting the firewall, so I useda 5/8" stubby wrench for those.
The only torque wrech I used was an inch pound one. I also found that to get the lower power steering pump bracket bolts out (to move the pump and bracket forward for clearance) was to take the lower section of the air box out. I could then get those bolts out from the top alot easier than from below. I also cut the heads off a few bolts thatI had that treaded in where the manifold bolts go to use as guides for putting the manifold back on.
The fuel pressure and return lines at the back of the manifold are, or at least on mine, 5/8", not metric. My flare nut wrench was too long and hitting the firewall, so I useda 5/8" stubby wrench for those.
#30
12-25-2006, 08:51 PM
RE: Intake manifold gaskets
I thought you had to take the manifold apart. In this article, it looks like there are bolts inside that have to come out. http://www.automotiveforums.com/vbul...d.php?t=486234
Coincidentally, my brother just picked up a truck cheap that needs intake gaskets.
Coincidentally, my brother just picked up a truck cheap that needs intake gaskets.