Just want to say first that you guys are great! I just bought a 1974 Maverick 4 door. This is my 4th Maverick now, the last one was back in 1981 when I owned a 1975 Maverick powder blue 4 door (kicking myself for selling it). At any rate after a long absence of having a Ford Maverick, my mid life crisis took over and well now I'm the owner of a 1974 4-door automatic transmission 250 cid Maverick. The problem I am having is with a exhaust valve gasket (I think). It needed to be replaced and upon buying the car I knew it due to the tank noise from the exhaust area. Well to make a long story short I took the car to a mechanic friend with a new exhaust valve gasket in hand and we found that the head pipe to the mainfold was cracked and a small chunk was missing. Even with putting the new gasket on the noise persised (no suprise). I took the car to local muffler shop to replace the first 24 inches of the head pipe and that went okay but the car STILL made the noise!! The local muffler shop says that it is the interior gasket in the manifold that is causing the problem. They say they could not detect the leak anyway but agree that the noise is still there. So..... Is there an interior gasket inside the manifold on this car leading to the exhuast? If so how hard is it to replace? How expensive would that be? I have another problem with the car flunking emissions. Too much Carbon Monoxide from tailpipe on 40mph test. What would be the first place to look to correct this? I just had the car tuned up so I know that is not it. Engine and trans have 24k on them since being rebuilt. Does the carb need to be "leaned out"? PCV valuve? As you know 74's do not have a smog pump or catalic converter. Any help on these issue would be appreciated!! P.S. Post with photo coming this week - getting car painted white tomorrow (was puke green).
I don't see any exhaust leak. I'm not sure if it is a sticky valve or lifter as the noise is very clearly from where the head pipe goes into the manifold. I just need to know if the muffler shop is pulling my leg to get rid of me by telling me that there is an interior gasket there. I don't want to go pulling it off to find out otherwise. BTW - No carb work was done when we did the tune up on the emissions problem.
i have a 73. with a 250. no emmissions testing. but anyways, i have sooo many rust holes in the tailpipe. it's the only real rust on the car.. makes it sound like a v8.. well more like a desiel..i know it does not help you.. sorry.. just well.. i dunno
Its hard to come up with an idea of what your problem is from what you describe. The only exhaust gaskets I can think of would be the exhaust manifold gasket (goes between the exhaust manifold and exhaust ports on the head). The donut gasket (between the front pipe and exhaust manifold). With it failing emissions, youcould have a valve problem. To my knowledge, there is no such thing as an exhaust valve gasket or interior manifold gasket, unless they are describing in different names what I have described. Mabey a compression check is in order here; that being based on failed emissions and (precieved exhaust noises?). Good luck and keep us posted. Jan
I have seen these exhaust manifolds warp so that they dont seal right. I had this happen on several cars over the years. If this is your problem, you could remove & examine the new gasket that you just put on. You should be able to see a burned mark where the exhaust is leaking by. If so, you can take the manifold to a machine shop & have them set it on a table belt sander and it will true it up.
Thanks! I will take off the exhaust pipe and look at the gasket. I think what you may be saying is true as the clasp that holds on the head pipe to the manifold is not completly snugged up (but tight as can be). Do you know of an interior gasket? Sounds fishy to me. On the other problem. Do you know if this year Maverick has a PCV valve? A carb guy says that perhaps the car is dumping too much gas in the carb that would cause excess Carbon Monoxide. I would like to try the simple things first to see if I can get it to pass emissions before I start spending a bunch of money to a mechanic.
Interior gasket? The only 2 gaskets as you were told are the donut a the manifold and pipe joint and the one where the exhaust manifold meets the cylinder head. Mavaholic is telling you the truth. There is such a mass of metal in that exhaust manifold that they can often get hot and warp. Resurfacing them at a machine shop is the only fixit there. Interior gasket? Maybe they are referring to the one at the cylinder head. Unless it was in a state that didn't require one, and I don't think there were any by '74, it should have a PCV valve to allow circulation of exhaust gasses back to the carb. Does your state/county require a 'sniff' test on a '74 vehicle? I thought I lived in a strict county but mine does not require it on cars without catalytic converters. Try running some carburetor cleaner through the gas tank, a couple of cans. I did that in my '94 Taurus (injector cleaner) when it would not pass, loaded it up with high octane gas, went back and it passed the next time. Seth
Yes Arizona requires the sniff test even on the 1974 models. I did put a bottle of STP gas treatment in it when I drove the car back to Phoenix from Albq. NM and did have high test in it when tested. I also had it tuned before the emissions test. The only good thing is that for 1974 and earlier cars you only have to spend a max of $200 and if it still does not pass they let you register it anyway unless it is double the allowable standard. I think the best bet is to have my mechanic friend possibly adjust the carb and use some spray carb cleaner on it as well. Anyone know if this year car has a PCV filter? If so I'm thinking that may need to be replaced as well. I will also look to see if the manifold gastet has any burnt spot on it to see where it may be still leaking. Thanks to all for the advise!
there isn`t anny pvc filter , U mite as well replace the pvc valve they are only 3.oo - 4.oo dollers in front on top of the yalve cover
I just had a thought, just something to check. On my I6 200, i had an exhaust leak for the longest time that i could NOT find anywhere. It turned out that what had happened is on the middle two cylinders, they had blown out the choke tube that ran down the middle and it was leaking exhaust out through the heater tube. Very difficult to detect and very obnoxious...i never found it till i finally yanked the 200 and put a 302 in.....
Also, if you really can't pass emissions, run your tank down really low and put a couple bottles of Heet in (the yellow one--methyl). You can pass just about any car by doing this (not that i condone cheating on emissions tests, but you gotta do what you gotta do...)
Thanks CACollo! I will be having a mechanic work on my car this Tuesday. He will probley adjust the float on my carb as it is dumping too much gas into the engine but I will remember your advise on HEET (actually never heard of it). On the exhaust leak, Where exactly is the heater tube? Do you have (or anyone) have a photo of where the heater tube is? If the leak is still coming from the exhaust valve gasket area the mechanic thought that perhaps putting on a second gasket there would work to quiet it down.
as mentioned above, I think by 74 all cars had PCV valves. If the PCV isn't connected the carb should have a stronger vacuum signal to the carb, which would make it dump more fuel, which won't help emissions testing.
No problem! The tube goes in the exact middle of the exhaust manifold, right up against the cylinder head. I don't know exact details of what Mavericks have it and which don't, but my '70 200 did. It is just a little hole that goes all the way through from top to bottom. It's worth checking.
