have a 03 gt with 31000 miles on it. Only has bolt ons with the addition of long tubes and a uncatted prochamber. Here is the emails I got from the people at Mac.

ME> I have an 03 Mustang GT that I just Installed Mac long tubes
and un catted prochamber on. The car has 30000 miles on it and aout 100
miles after the install the car started smoking at wide open throttle.
When I installed the headers, I left the egr tube unhooked for about
30-45 minutes and even turned off the egr valve with my diablo predator
tuner prior to starting the car. I am thinking that it is pulling oil
out of the valve covers threw the pcv valve due to the wide open
throttle. I want some answers on why this is doing this. I don't want
to hear that I am going to have to rebuild because of your product.
Please call me, or give me a name and a number where I can
call or have someone with some authority call. I have been reading a
lot of posts where people are having these same problems.


MAC> You need to contact Diablo and ask them to help you get the settings
programmed right on your car. It sound to me like some of the setting
might be conflicting with each other and that is the problem you are
having. Changing header and mid pipe will not cause your car to smoke.


ME> A tuner will not cause an engine to burn oil! I have had this car programmed for about 10000 miles and never has the engine used oil. I put long tubes and a prochamber on, 100 or so miles later, the car burnt one quart of oil. Smoking pretty bad at wide open throttle. I know that I am not the first person to have this problem with your product, due to what I have read on different forums. These people are getting the run around just like you are giving me. I want some answers or talk to someone who knows what they are talking about. I have the resources and the capability to get to the bottom of this. So I suggest you get with some of your co-workers and see if they have had any complaints. I want some straight answers. Please let me know something ASAP.



MAC> I want to assure you that this is not a header problem. Here are some of the reasons this is happening and the remedy. Ford has always had a concern when it comes to the valve guides because we saw this on the early Cobras before they fixed with the recalls on the intakes on the 03-04. At wide open throttle the car is producing at least 110 psi oil pressure and when compounded with the return system of these vehicles the oil is not being returned to the sump quick enough causing this effect. This will also happen on blown cars and when working with Kenne Bell they would always take the PCV off and hold the car and half throttle and see if there was smoke coming out of the valve cover. If this was the outcome then they would replace the valve guides with hardened ones. This problem has always been there but has become noticeable due to the increased scavenging effect the headers have on the motor. Also running synthetic oil or oil over 30w will cause this because it takes longer for it to return to the sump. What Kenne Bell, Vortech and Whipple have done is run a windage tray on the crank to keep oil down in the sump from splashing up on the crank. I hope this has answered some of your questions about this product. I know this can be frustrating and if you have any further questions please let us know.


ME> You know, this is b.s. I don't like driving around in a new car, with 30,000 miles on it, smoking like a freight train. I think this should be advertised by your company that your product could cause excessive oil consumption. My local Ford dealership is going to look into this and I will let you know what they conclude. I do not buy that line about oil being pulled past the valve guide. Most people that I have talked to that has had this problem said that the engine walls were scared and the rings had metal shavings inbedded in them. They think that the EGR is the pathway for slag and other material from the headers. I turned off the EGR with my programmer, left the tube off and let it run for about 30-45 minutes before i hooked it up. Also I run 5w20 Mobil one in the car. I have three mustangs and never will I buy another Mac product. Everyone I talk to, race with at the track, and talk to on forums will know about my experience and your product. I can't believe that a company of your size will not take any responsibility for this. I will being letting you know the outcome.


MAC> When you have 40 years of experience and not some forum opinon then we can talk. If you want to be abrasive then I can’t help you. You can call Art Whipple at Whipple, Mark Sanchez at Advanced engine Management or Vortech Engineering or Granatelli Motorsports. They all have more experience in these cars then anybody and will tell you the same thing. If this was an occurring problem with all of the headers we sent out we would have done something but you had your mind made up before you even talked to us. We stand behind everything we sell and have been in business for 40 years making parts for cars, trucks and motorcycles. If you want to take there advice and not the advice of experts then that is up to you. We have sold over a thousand sets of these headers in a two year period. Also taking a car into most dealerships with an aftermarket off road header will usually void the warranty just a heads up.





ME> First of all, all of the places you are refering to run superchargers. This is a stock gt mustang. I have checked into what you said about the oil being sucked past the valve guides from a few people that has had this problem and all of themsay thatthey have been told the same garbage that you are spouting. They had hardened valve guides and new valve seals replaced and same crap. I am shocked that a company as big as Mac will not take any responsibility for this. I am not talking about a high horse power engine here, I am talking about a stock 30000 mile gt. The reason I bought the headers is for sound basically. I damn sure made a huge mistake. One quart of oil every 200 miles, that is bs. You know that this is a problem. Why not try to get to the bottom of this. There has been several of my friends that sent letters in to a certain Ford magazine about this, so I am sure we will see a write up about it. I will not stop until I get satisfaction on this matter. Bottom line, your product caused the problem. By the way, there is no warranty on my car and the guy who recommended your product installed some on his car and it is also doing the same thing. So we will find out the problem.



MAC> Show me how this header can cause oil consumption without any other underlying problem. We have sold THOUNANDS of these headers and don’t have a problem. If you do found out what is wrong with your vehicle please do pass it along so I can relay the info to everybody else who doesn’t know anything.

I asked the guy togive me his name so I could tell his boss how he is conducting business for his company but still no email. This is crazy. I am thinking about writing a piece and send it to Muscle Mustang and Fast Fords to see if they will put it in there magazine. If there is anyone out there who wants to try to do something about this, please write me

ORIGINAL: oxfordgt

The same thing happened to me but it is not totaly the headers fault. What happens is the headers flow better then any other. To good for a stock mustang with stock cams. What happens is that the exhaust gases want to come out of the heads in the up direction and then down and this is exactly the way the #7 and #8 tubes are designed. During the valve overlap it pulls to much fuel out of the chamber which is ment to cool the exhaust valve seat. Which in turn leans out the cyl. A fuel injected engine can not adjust to this like a carbarated one can. Once the cyl is to lean it gets to hot and detontion occurs. You get broken ring lands which score the cyl walls. That is where you are burning oil. It is getting past the rings.

The way to stop this from happening is to tune it richer before you start the engine for the first time.

I'm sorry to give you bad news but its time for a rebuild. Do a compression test and you will find out what cyl wall is fuked.

I put a warning out on here about a month ago I'm sorry you didn't see it.

I was told this by my engine builder who has tested all of the brands of headers. He said he found that Mac headers do this but its not because they are of poor quality. He uses only Mac longtubes on is race engines. I am rebuilding my engine now because of this. I am boreing it .020 over to get rid of the scratches and stroking it with all fully forged parts. I will be reinstalling the Mac longtubes and have no worries about the new engine.

If you have anymore questions feel free to ask.

ORIGINAL: oxfordgt

No they wont do it because they don't flow as well as Mac. If you have a tuner then it is completly safe to get the mac headers.