Intake manifold October 17, 2012, 08:41:21 PM Well, this is the third time I have replaced the intake manifold gasket and I'm still getting coolant in the oil. First try the I used the wrong RTV. second time I only used a little on the valley gaps (dry otherwise) and this last time I put a little Permatex ultra blue around the coolant ports on both sides of the gasket. This last time I also put four 3" all thread in the four corners to make sure it guided the manifold straight down. I don't think I could have a cracked head, I haven't even ran it much since I started working on it. Maybe a warped manifold? I think I'll run a straight edge along it this time and see if I can see anything. If that's my problem do I get it milled? Quote Selected
Intake manifold Reply #2 – October 17, 2012, 08:47:28 PM Sorry, 1986 cougar 5.0 engine w/FI. Quote Selected
Intake manifold Reply #3 – October 17, 2012, 09:15:38 PM Are all of the bolts torqued? Did you tighten them in the right sequence? Did you let the sealant set up a bit before running it? Are you using quality gaskets? Quote Selected
Intake manifold Reply #4 – October 17, 2012, 09:21:10 PM All the bolts were torqued at 7 lbs., 15 lbs. then last 24 lbs. in the sequence according to my manual. I did not try to start the car until the next day (about 18 hours later). I've only used fel-pro gaskets. Quote Selected
Intake manifold Reply #5 – October 17, 2012, 10:15:31 PM have you ran a compression test to see if you might have a blown head gasket? Quote Selected
Intake manifold Reply #6 – October 17, 2012, 10:35:54 PM Good idea! That's one thing I can do without running the engine. Wouldn't that have been a problem before I started to work on it? Would having two dead fuel injectors and the rest dirty really add enough pressure to take out a head gasket? I guess if they are 26 years old, anything is possible. Thanks! Quote Selected
Intake manifold Reply #7 – October 17, 2012, 10:58:26 PM its one more thing that could put coolant in the oil and easy enough to check. Quote Selected
Intake manifold Reply #8 – October 17, 2012, 11:14:48 PM I am glad that you used dowel pins (made of allthread) to locate the manifold. It makes it a piece of cake to install. However, all felpro gaskets are to go on dry, with the exception of cork valve cover gaskets, but even then, the adhesive is just to hold the gasket in place and not used in an attempt to seal anything, because the cork can easily do that all by itself. The RTV should ONLY go in the corners of the front and rear seals at the intersection of the heads and the block. Only then, do you install the front and rear seals and then the intake. I didn't take pictures when I assembled the 5.0l in Dad's Exploder, but no leaks and it fired right up the first try. You said that you used felpro gaskets, does that include the silicone front and rear seals? If so, these should also go on dry, with the exception of the ends being set into the bead of RTV(oil, gas, coolant resistant) at the corners. Here is a picture of what I am talking about. I also noted the location tabs that intersect with the head gasket tabs. I seriously doubt that the manifold is warped, though I suppose anything is possible. More likely is blown head gasket or cracked head. That flourescent kit I was telling you about sure would come in handy right about now, eh? Quote Selected
Intake manifold Reply #9 – October 18, 2012, 12:18:30 AM Quote from: Crazy88;400694I am glad that you used dowel pins (made of allthread) to locate the manifold. It makes it a piece of cake to install. However, all felpro gaskets are to go on dry, with the exception of cork valve cover gaskets, but even then, the adhesive is just to hold the gasket in place and not used in an attempt to seal anything, because the cork can easily do that all by itself. The RTV should ONLY go in the corners of the front and rear seals at the intersection of the heads and the block. Only then, do you install the front and rear seals and then the intake. I didn't take pictures when I assembled the 5.0l in Dad's Exploder, but no leaks and it fired right up the first try. You said that you used felpro gaskets, does that include the silicone front and rear seals? If so, these should also go on dry, with the exception of the ends being set into the bead of RTV(oil, gas, coolant resistant) at the corners. Here is a picture of what I am talking about. I also noted the location tabs that intersect with the head gasket tabs. I seriously doubt that the manifold is warped, though I suppose anything is possible. More likely is blown head gasket or cracked head. That flourescent kit I was telling you about sure would come in handy right about now, eh?This is how I did my intake when I swapped on Edelbrock Performer heads this spring. The alignment rods help A LOT. I just used some bolts I cut the heads off of instead of all thread. I used the Felpro MS95952 intake gasket set for EFI GT40 intakes. It has graphite/steel gaskets and the blue rubber end seals. I just put the gaskets on dry, put a strip of Ultra Black RTV in the corners, put the end seals on, put another strip of Ultra Black on the corners, lowered the manifold on, and the torqued it to spec in three steps. On the final torque step keeping going around till the bolts stop moving. I had to go around my lower intake 4 times at the final torque spec till all the bolts stopped moving. I fired the engine the same day I put the manifold on (about 6 hours after doing it) and it was fine. No leaks no problems.Also a FYI on the alignment rods: the thread is the same as the thread in the bolt holes for the upper intake manifold. You can use them as alignment studs there to keep the upper to lower intake gasket from moving around. Quote Selected
Intake manifold Reply #10 – October 18, 2012, 12:39:10 AM Quote from: thunderjet302;400699I just used some bolts I cut the heads off of instead of all thread. I used allthread since it was $1.34 for two feet of it and was more than enough to make my own set of 3" studs. On the final torque step keeping going around till the bolts stop moving. I had to go around my lower intake 4 times at the final torque spec till all the bolts stopped moving.[/QUOTE]I use a 'click' type torquewrench and I click once, back off just a bit and click the second time. I never, ever try to get the bolt to stop turning, as it is entirely possible that stretched bolts can continue to turn and suddenly snap... making for a really bad day... Quote from: thunderjet302;400699I fired the engine the same day I put the manifold on (about 6 hours after doing it) and it was fine. No leaks no problems.I actually waited until the next morning, but that was only due to the extra reassembly necessary for the engine swap. Quote from: thunderjet302;400699Also a FYI on the alignment rods: the thread is the same as the thread in the bolt holes for the upper intake manifold. You can use them as alignment studs there to keep the upper to lower intake gasket from moving around. I knew that, but it is a good tip, if you can use it. On the Exploder, you can't do it due to the way that the upper manifold nestles in just under the cowl. Quote Selected
Intake manifold Reply #11 – October 18, 2012, 01:03:46 AM I did the intake gasket just like you said the first and second time. I would be willing to bet it's either a cracked head or a blown head gasket. Hopefully, just the gasket. I need to check out the heads and make sure they are alright. Gives me an excuse to clean them up as well. I guess I will be adjusting the valves, been a while since I've done that. I might polish up the valves also being they will be available. If I can get them to not leak with a little elbow grease, why not. Looks like shop class is off to another chapter. I can't wait to see what I find! Quote Selected
Intake manifold Reply #12 – October 18, 2012, 06:42:57 AM I install studs and leave them in!!!! This also holds the side gaskets nicely in all the hole positions.Then i use a flat washer with a split washer then a nut. Use a stud with course threads on one side and fine on the other . This way you get more consistent clamping. No need for the alignment studs as you already covered that part with studs installed permanently. I personally never use the front and rear gaskets on the block to manifold seal. A thick bead of silicone is the ticket for that. I think i invented it as i have been doing it since i was 15. Not only on FORDS. But all other engines that have this setup. It works much better. 88 is correct no silicone on the side gaskets. Fel Pro does not recommend it. Just a thoughtNote make sure the manifold gasket is not slipping down. Normally i use HIGH TACK to hold them in position and that works great. I know the tabs are their for that. But sometimes they dont work correctly are are missing on an old engine. Quote Selected
Intake manifold Reply #13 – October 18, 2012, 07:30:10 AM Have you spent any time looking at the timing cover? Quote Selected
Intake manifold Reply #14 – October 18, 2012, 10:44:37 AM Tom, What I did was after I put in the all thread, I put all the other bolts in place (just snug), then I took out the all thread and replaced them with the original bolts. Every time I have taken the manifold back off the gasket has been right where it should be (under the tabs and no movement). I think I'll try the bead on the front and rear of the manifold next time. I did not put any RTV on the end gaskets other than the top four small cracks. I also took my time the last two times I replaced the gasket and I was very cautious, that's why I would bet something else is going on. TFYK,Honestly, no the timing gasket never crossed my mind. I take it the only way to check it is to replace it? I don't see any leakage from it. I will be taking my heads off today and hopefully I will know more. Lately, I've been buying stock in that liquid gold, five quarts at a time. If I find out the head gaskets are shot, I will put the intake back on dry except for the valley cracks. Either way the intake and head gaskets are going to be replaced. Good news is that the first start up the car sounds solid and runs smooth.... then comes the smoke. Quote Selected