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3.8 liter Mustangs

09-17-2009, 10:20 PM
All Mustangs with the 3.8 liter engine are susceptible to a cracked exhaust pipe on the passenger side just before the catalytic convertor. This is caused by the evaporator core drain for the a/c just above the exhaust. When the engine is to temp and the exhaust is nice and hot, you're running the a/c because it happens to be blistering hot outside. Well the moisture drips exactly on the exhaust right at the weld where the pipe and catalytic convertor meet. This causes a heat and cool effect working it like a coat hanger being bent back and forth. Eventually it cracks and keeps getting bigger. Makes an awful exhaust leak noise. At our shop we just drop the y-pipe assembly and weld the crack and send the customer happily down the road. Watch out though... some shops will say they cannot do it unless the y-pipe assembly is replaced costing in the realm of $400-$600. It is an easy fix, costing no more than $175. Got some pics, enjoy!

09-17-2009, 10:55 PM
Pretty neat Fix! and I'm all for fixing vs replacing so great advice and your shop is obviously doing it the right way for the customer. Great to see that sometimes...

09-18-2009, 06:21 AM
Does any thing get done about the ac dripping onto the exhaust? If not wouldn't the weld crack again in a few years?

09-18-2009, 06:43 AM
Hi All,

My friend had the same problem with a 2000 v6 3.6L mustang. His had a dual exhaust which actually caused more stress on the manifold. The crack sounded very loud as if he had a V12.

To fix did run him a a few hundred.


09-18-2009, 09:56 AM
Yeah it probably will crack again. But the rubber elbow from the evap is hard access. The elbow installs from the inside off of the evaporator case. The only true way is to fix is to remove the dash then the evap case and try to fit another or modified rubber elbow. Most people don't want to pay to have their dash and evap R&R'ed. It has been tried in the past where a tube has been fitted inside the rubber elbow to reroute the drip. Unfortunately it is a 50/50 that it will clog from moisture and dust elements catching on the inside lip. I have had to clear those too. I have seen about a gallon of water drain from these when unclogging them. And yes Simon it does sound raspy.

09-19-2009, 09:44 PM
The fix looks much beefier than the original weld. Should last a bit longer the second time. Maybe a shroud or shield could also be welded on to deflect the A/C drip?

09-20-2009, 11:44 PM
Maybe a shroud or shield could also be welded on to deflect the A/C drip?

Good call... I will keep that in mind next time one comes in.

Just for the record we haven't had one come back yet for the same issue.

09-27-2009, 10:36 PM

Good to see there are still some shops around with the customer's best interests at heart. - - Kudos to you - I wish you were in my area!!

Art R.

09-28-2009, 10:18 PM
Art the shops are out there. Very few it seems anymore. Ask alot questions and there should be no grey area in the answers. If something doesn't sound right, ask more questions. You will find that alot of shops do alot of double talking, the good shops will be straight with you. If you find a good shop, stick with them. Repore from a customer is just as important as repore from a shop. You will know if someone is treating you right. Thanks for the Kudos.


10-25-2009, 10:00 AM
The fix looks much beefier than the original weld. Should last a bit longer the second time. Maybe a shroud or shield could also be welded on to deflect the A/C drip?

I agree, the fix looks much beefier. Nice job on the repair.

01-08-2010, 09:48 PM
Looks good great weld job!!! I will be doing a 3 inch straight pipe on my Bmw e30 turbo soon!! I will post pics up soon!!!

03-19-2011, 11:55 PM
Good job on the repair; hope it lasts a long time.

04-19-2011, 12:24 PM
Good job, I have a 2001 that needs the same repair I guess its more common an issue than one would think. When I get the garage back up I'll attempt the job.