Hi Everyone, I have a big exhaust leak somewhere. Best I can tell, it's at the front manifold behind the ac compressor. I'm just wondering if anyone has had long lasting success with a certain brand or type of exhaust manifold gasket. Mahle and Fel-pro are looking like pretty good to me. I already sprayed PB blaster everywhere and I plan on starting this job today so I want to order studs and gaskets right away. It does seem like someone has been in there before because the dipstick isn't attached and I don't see a heat shield I've read about in other threads. I bought this car in June and theres no way it'll pass smog in CA with this leak. Also, does anyone use copper spray on their gaskets? I use it on my quads when ever I rebuild the top ends but I haven't read of anyone using it on the fieros. I've also used it on my old camaro's engine as well. I like it and it gives me piece of mind. How do you think it will hold up on the exhaust gaskets?
Is likely Not a gasket problem but warps flange(s) or crack manifold. If has warp flanges then any new gasket won't last long.
Don't use any sealer on exhaust gaskets of any type. Heats up and burns then do nothing to seal. Worse, many sealers are Poison to O2 sensor and cat.
Note that Many other gaskets are installed Dry w/o Sealer too. Some like engine oil pan sets need sealer only where has seems. Some time you can use Pematex High Tack sealer/"glue" to hold a gasket in place... Examples: Duke side cover over valve lifters. You only "glue" the gasket to the cover so gasket stays put while installing the nuts. (4 rubber parts on the studs don't need anything.) Most Valve Covers do not use gaskets w/ sealers. But Some covers and other parts are made to work w/o a gasket and mods to use RTV silicone instead.
most OE types are same way... Sealers cause more problems w/ gaskets to fix a problem like Felpro product labeled as PermaDry, PermaTorque and others.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
When you replace your gaskets some people have had success with these VW type. Each port gets its own gasket: Click Here
When you have your manifold off, check for alignment of the three flanges with a straight edge. Patrick references a belt-sander method that a friend of his used to realign the flanges at home and stop the leaking. I searched but couldn't find the actual belt-sander posting itself: Click Here
Thanks for all the input guys. I already ordered the stud kit and fel-pro gaskets from TFS and a Mahle gasket from ebay so I can compare them and see which one might be better. If anyone is interested in the differences, I can post the findings.
QUOTE]Originally posted by Notorio:
When you replace your gaskets some people have had success with these VW type. Each port gets its own gasket: Click Here (Sorry, still trying to figure out this quoting thing)
Thanks! I'm going to look into these and compare them to the other two. I was leaning toward the EMPI's but I'm still trying to find copper ones like pmbrunelle mentioned.
I made a little progress the last couple of days. The Y pipe is removed and I decided to removed the vent tubes and heat shields from the trunk side as well. They looked like they could get in the way. The AC compressor was a real pain. I had to hammer a ratchet with a pickle fork and mallet to break the middle bolts loose while being careful not to slip and break the rear glass. I got two broken bolts on the firewall side Y pipe flange but the Y flange to the cat had to be removed with an impact gun since the damn previous mechanic decided to use a nut and bolt on one side of it. I spun my ratchet on there for a what seemed like 5 minutes until I reliazed I shoud check to see why it's spinning. The nut was frozen so I was willing to snap it with the impact wrench. To my surprise, it came out intact.
Does anyone know if the upper AC bracket needs to come off? I see 3 bolts on the face of the engine. Are there any hidden out of sight?
Congratulations , consider this project as the initiation to being a Fiero owner. I'm 1 of many and I was fortunate to do the job in a garage at home so I could nibble at it at my leisure. 1 guarantee is it will always be the manifold behind the rear window glass. This project turned out to be a terrible experience. Broken manifold bolt became a reality. Bought a right angle drill and special short bits to get into the tight spots, with no luck. Pulled the head but first had to remove 2-3 layers of intake manifolds, injectors, and on & on. Even broke off a spark plug and had to drill that out. At that point I figured I may as well go whole-hog and pull the other head. All this pain & suffering over 1 broken manifold bolt! Ended up buying a drill press and some taps. Replaced the bolts with studs and used VW gaskets. My 3800sc swap was a much easier task. Something to consider...
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
Congratulations , consider this project as the initiation to being a Fiero owner. I'm 1 of many and I was fortunate to do the job in a garage at home so I could nibble at it at my leisure. 1 guarantee is it will always be the manifold behind the rear window glass. This project turned out to be a terrible experience. Broken manifold bolt became a reality. Bought a right angle drill and special short bits to get into the tight spots...
Other than not having the luxury of a garage, this sounds very much like my adventure several years ago, posted Here. It was by far the worst experience I have ever had in over 50 years of working on my vehicles.
I wound up taking off my A/C bracket, but i do not remember if it was in the way for anything. There are only those 3 bolts.
I decided to remove the bracket, too. I figured since this is my first time doing this job, I should get as much out of the way as possible. It will make it easier to assess every option to any problem (hopefully none) that might arise. Thanks.
Other than not having the luxury of a garage, this sounds very much like my adventure several years ago, posted Here. It was by far the worst experience I have ever had in over 50 years of working on my vehicles.
Hey Spoon and Patrick, thanks for sharing your horror stories with me. I'm hoping to avoid the same issues but at least I know that if I do run into prolems, I can reference all your previous solutions. Oh, and now I'm petrified to even get started with the header removal, lol (and shaking in my boots).
I'll let you guys know how it goes. I'm waiting for a few things to get delivered so it may not be until next week.
I was able to remove both manifolds without breaking any of the bolts. That's the quick part.
The long part: I noticed most threads on removing the bolts only suggested spraying PB Blaster multiple times for a few days and letting it soak in with a few hopes and prayers that none of them would snap. Well, I decided to do whatever I could to give myself any advantage over just crossing my fingers.
A Little Backstory: A while back I was rebuilding the suspension on my Ram truck. It's an '04 and I bought it new. The ball joints were shot and needed to be changed out. That means the rotors and hubs, and spindles had to come off. I knew that the brake rotors had never been removed because when it finally came time to do the brake jobs, I could never remove the rotors , they were welded in place from all the rust that accumulated for 18 yrs. I fought them, hammered them, heated them, and cursed at them but nothing worked. I was just about to give up and go to a shop when I came across this video.
I already had a cheap air chisel from HF that I used to changed some A-arm bushings on my camaro, so all I needed was the hammer head and the HF water sprayer. A quick search on Amazon and they were delivered in a couple of days. The driver side was the toughest and took about 10-15 min but it finally came off. The others were a little easier. That video is the real deal.
Back to the Fiero: I decided to try this method out on the manifold bolts. I had already sprayed penetrating oil for about 4 days. It could have possibly been the reason I didn't snap any but I wasn't going to leave it up to chance at the time. Besides, I had already broken two off at the manifold to Y-pipe flange using just the oil. So I grabbed my air chisel and started going to work on the trunk side bolts being really careful not to damage the tubing. After about 20 min of quick hammer pulls and water spraying, I decided to check the bolts. THEY WERE LOOSE. It took no force to spin them by hand with just a socket on an extension. I thought to myself, either this method really works or they were loose to begin with and that's why I had an exhaust leak. I really should have checked them first. Anyway, I chose to believe that it worked and went ahead and started planning my attack on the firewall manifold.
First a Disclaimer: This is by no means a tutorial or "How to". This is only a "this is how I did it and probably got lucky".
You can cause major damage to your manifolds, scratches, dents, or even holes.You could break off a bolt head if you don't hammer them squarely. The bolt heads will get deformed and you might not be able to get a socket or wrench on them. I had to use all my arsenal, 6-pt, 12-pt, and even spline sockets to be able to grab onto some of the heads. I also had rounded nut removers ready just in case but lukcily I didn't need them.
Here we go: The first thing I did was get some protection for the manifold. It was tough to stay square to the bolt head and not slip off. I knew that I was going to be in awkward positions and would not be able to secure the air hammer confidently with two hands. I went to Lowe's and got a couple of steel plates from the construction area, I only used one of them though. Next time I might just get one the length of the header and maybe 1 inch or so less on the width. I wrapped it in duct tape so it wouldn't scratch anything too much. It seemed to work out ok. Zip ties were used to secure the plate in place.
I also needed a short barrel air chisel/hammer(could be called either) due to the tight space between the firewall and engine. I ordred a Cambell hammer from ebay but I got antsy and didn't want to wait 2 more days so I took a shot at HF and they had a one for like 15 bucks with a coupon. It ended up being the same length (5.25") as the Cambell. I also used my shortest hammer head. Total length was just hair above 7 inches, which was just barely short enough to get in there. One more inch shorter or one more inch of space would have been way better. Cylinder #2 bolts were the most difficult followed by the top stud on #6 due to the added length. I had to use a small squirt bottle to spray. Another set of hands would have been really nice so they can spray the water for me. Having to get my hands and arms in and out every couple of minutes to spray, hammer, spray, and then hammer again was very tiresome. I ended up with a ton of scratches on my wrists and forearms.
The Findings: All kinds of bad found on the heat shield. I don't see why anyone would install this, especially without gaskets on both sides. Horrible design IMO.
The bolts were in pretty bad shape. A few of them had a lot of rust and one of from the trunk side was even missing some threads. I feel some probably would have broken off if I had left it up to chance. Again, maybe it was just luck and not the hammering but I would definately use the hammer again if I felt the need.
Thanks A_Lonely_Potato. I checked over the manifolds. The trunk side header looked pretty good.I didn't see any signs of leaks or cracks. The flange seal areas didn't show any obvious signs of leakage.
The firewall side, on the other hand, wasn't as pretty. There's a really ugly previous repair that I'm going to have to grind off. It's just too ugly. t doesn't look like it's leaking but it's possible that all pressure was already exiting from the heat shield areas. You can see the crack on the inner flange weld. My plan is to grind off the ugly weld, weld all the flanges and then port the insides. I'm still waiting for Rodney's header jig so I'll have to play the waiting game for a few more days before I can get started.
quote
Originally posted by A_Lonely_Potato:
check those logs for cracks!
Is there anything else I should be looking for? Any common areas that are notorious for cracking?
Originally posted by MaxxPower1968: All kinds of bad found on the heat shield. I don't see why anyone would install this, especially without gaskets on both sides. Horrible design IMO.
Originally posted by MaxxPower1968: Is there anything else I should be looking for? Any common areas that are notorious for cracking?
So the Fiero 2.8 manifolds are plagued with problems; I would say this is because they are long straight tubes fixed rigidly to the cylinder head with short stub pipes. As the exhaust warms up the manifold, the manifold tries to expand (that's what temperature does to most materials), but it is kept from expanding because it is restrained to the cylinder head. So something ends up giving...
If there are no exhaust/emissions visual checks you must pass, I recommend retrofitting bellows couplings in your Fiero manifolds to reduce the stress (which causes cracks).
Hey pmbrunelle, yeah the bellows are pretty nice and they do a great job at absorbing vibration. I work at a big rocket company in Hawthorne and we use bellows on many tubing assemblies to deal with expansion, vibration, and variations with extreme temperature changes. Unfortunately, with living in California, I wouldn't be able to get away with a modification like that on a smog required car.
A quick update on the situation: I grinded off the ugly weld from the firewall side manifold and, just as I suspected, there were leaks in the seal. So I'm going to have to reweld it correctly. I had both manifolds hot tanked at my local machine shop to try to minimize contaminants getting into the welds. Hopefully I can get it done next weekend.
[This message has been edited by MaxxPower1968 (edited 11-11-2022).]
I have a set of the FEL-Pro from TFS, a set of MAHLE and a set of VW Empi gaskets. I haven't had a chance to do a comparison inspection yet. I want to see what the differences in materials, thickness, and maybe post compression. I'll post photos if anyone is interested. I still have a ways to go before I can get around to installing. I have to decide what I'm going to do about the heat shield. From what I've read, it's more of a splash guard to keep oil from causing a fire. Anyway, mine is all pitted and damaged from the exhaust leaks. I tried to grind it smooth but it's a little too thin to do both sides.
[This message has been edited by MaxxPower1968 (edited 11-11-2022).]
The V6 Shield are for both... Helps keep oil leaks away from the exhaust. Helps keep exhaust IR heating the valve covers that tries to prevent Cover Gaskets/seals cooking causing leaks.
If wreck, make replacements out of many types of sheet metal.
Yeah, I was thinking about making one out of stainless or aluminum. I haven't decided yet. Has anyone had good results with either material? What thickness?
GM didn't think that the RH valve cover needed a similar shield for protection from exhaust manifold radiation.
The valve cover gaskets are silicone; in my experience they seem to stay soft/pliable, as if they are not damaged by heat. I don't run this shield on my Fiero.
If you do want to make a replacement shield, you should have equal or greater sheet thickness than stock. Thickness is key in setting the shield's natural frequencies so that it doesn't vibrate itself apart.
Steel is heavier (by about 3x), which makes it more vibration-prone, but steel is also about 3x stiffer than aluminium (which reduces tendency for vibration), so overall the two effects balance each other. Neither steel nor aluminium is more likely to vibrate than one another.
Since you are stuck with this huge failure of a design, there is either cracking, or sliding somewhere (on gasket surfaces), with thermal expansion of the manifold.
Because of the potential for sliding, I would choose stainless steel, because I think it would hold up better to sliding than aluminium.
GM didn't think that the RH valve cover needed a similar shield for protection from exhaust manifold radiation.
The valve cover gaskets are silicone; in my experience they seem to stay soft/pliable, as if they are not damaged by heat. I don't run this shield on my Fiero.
Were the fire problems only isolated to the early 2.5?
As far as I know, the 2.8 never had issues with connecting rods punching holes in the block (which would then allow crankcase oil to spray all over a hot cat).
IMO, there's very little chance that a shield mounted on the forward side of a 2.8 will ever be of any use. However, there's a much higher probability that it'll contribute to an exhaust leak. I purposely left it off both my '86 GT and '88 Formula.
IMO, there's very little chance that a shield mounted on the forward side of a 2.8 will ever be of any use. However, there's a much higher probability that it'll contribute to an exhaust leak. I purposely left it off both my '86 GT and '88 Formula.
I'm really leaning toward not using the heatshield. If the rear doesnt need it, then I'm thinking the fwd side doesn't need it either (I coudl be wrong). I might make a new one and perhaps think about reinstalling it in the future. I think I may just use some type of insulating shielding on the wiring to add some protection and run with it but monitoring things between oil changes. I'm going to work on porting the manifolds and welding them up in the next few days.
+1 for chuck it, never had issues without it on mine, DEI makes some nice products for heat including some formable heat shield material that you could put over the manifold if you were worried about heat.
Or go ahead and weld some studs to the manifold to attach a make -it-yourself heat shield to.
Or make a new heat shield or modify the one you have to attach to the exhaust manifold bolts on the other side instead of being sandwiched between the flanges and head.
If you are worried about oil dripping on the cat, I think a heat shield over the cat attached to the exhaust would be a better solution. Can also wrap the cat in DEI products, whether the insulating lava wrap or the formable heat shield material I mentioned.
I would not recommend wrapping the manifold in the lava/titanium wrap though, works well but makes them corrode quickly.
Porting the manifolds definitely makes a noticeable difference in power, they are quite restrictive.
If you have a polished countertop or glass table surface, you can take some sandpaper and tape it to the surface and run the manifolds over that to flatten them, I like to use WD40 on the sandpaper, makes it slide easily. Get good sandpaper or it will disintegrate. Or use a belt sander if you have access to one.
... but some people <cough, cough> toss 'em.
