Cadillac CTS-V - OBX headers leaking-- what to do?

Hello All,

I'm hoping to get some feedback from you guys, given how much accumulated experience there is on here. I had my OBX headers installed by my local mechanic. Everything was fine for two days, then I started noticing a drop off in throttle response. I popped the hood and heard the tell-tale sound of a header/manifold leak-- that thhhck thhhck thhhck sound that increased with revs. Upon shutting off the engine, I heard a sucking sound like there was negative pressure being equalized.

This is only on the driver's side. Like I said, it was fine for a couple of days before the leak started. The mechanics used the gasket that came with the OBX headers. I realize now this may have been a mistake. I also don't know what kind of bolts they used-- I assume OEM.

When I noticed the leak, I was late for a meeting, and didn't have time to remove CAI and plug wires, so I couldn't get to all the bolts. I tightened the bolts I could get to. I could got a quarter turn on 3/4 of them. This diminished the noise, so I guess diminished the leak.

Today, I'm gonna remove the wires and CAI so I can get some room to work and try to tighten the remaining bolts. Hopefully, this will take care of the problem. However, I'm not hopeful.

I want to be prepared to replace the header gaskets and bolts, and this time I want to use the best available. My wife uses this car to transport our baby, so I want to minimize the chances of a leak as much as possible.

I found this awesome illustrated post on headers installation on cadillacfaq that was written by StealthV. I can see now why he is so missed around here: http://www.cadillacfaq.com/faq/answe...ers/index.html

In that thread, he recommends "Percy's Seal4Good dead-soft aluminum exhaust manifold/header gaskets were used, part number 66032", and "ARP stainless steel exhaust header studs, part number 434-1301". I plan to buy these, unless any of you guys have any different recommendations.

So, what do you guys think of the above? I'm slowly easing my way into doing my own work on the car, and I think this will be a good next project.

Thanks!
DAC

I took one look at the gaskets that came with the headers. Put the stock gaskets back on with no issues.

Hello All,

The mechanics used the gasket that came with the OBX headers.


silly mechanics...

I'd have the guy u paid fix his fuck up

silly mechanics...

That was my noob mistake. I thought that was clear from my post. Now I know to use (or have my mechanic use) a good gasket.

The ARP hardware is tits.

However, after losing a few of the 12 point nuts and more after the Monster clutch fiasco, I got smart and used these:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400178033051&ssPageName=ADME:L:OC:US:1123

No more loose headers.

I've had lots of trouble in the past with blown header gaskets and backing out bolts so when I did my headers I used these and have been thrilled with the results. Zero issues with leaks!

GM MLS Gaskets:

http://www.texas-speed.com/p-387-gm-multi-layer-steel-exhaust-gaskets.aspx

Stage 8 Bolts:


http://www.ebay.com/itm/330768202186?hlp=false#ht_1443wt_1031

Any bolt is fine really just put a little antiseize on them if you replace them. I used Fel Pro header gaskets after I had to replace the kooks gaskets, and then brand new GM MLS gaskets becuase they all leaked. I have used fel pros ever since and never had an issue.

BTW replacing thegaskets while the headers are on the car is actually very easy.

Thanks, gents. Am I OK driving around with a small leak for a week or so till the new gaskets come in?

Probably, but just remember to take it easy. Your fuel mix is probably off and if you'll probably run a little rich. If you drive like a gentlemen (3k rpm or less) you shouldn't have any trouble while you're waiting for parts.

I reused my stock gaskets after knocking any carbon deposits off with some steel wool and carb cleaner. OBX cardboard gaskets found their way to the trash.

Stock gaskets (even used ones) and OE bolts. Not surprised you got 1/4 turn on all that you could reach, they are only torqued to 18 ft lbs.

Easy way to replace them...
1. Get new GM exhaust manifold gaskets
2. Remove everything required to get to the header bolts (plugs, wires, etc)
3. Remove all the bolts on both headers EXCEPT for the two bolts at either far end of the headers...leave them loose so the header kind of hangs there.
4. Take the new GM gaskets (ensuring they are for the correct side) and snip the two end bolt holes down, so the gasket can hang on the two outside remaining bolts while you start all the other ones.
5. Torque to 18 ft lbs (just get it close, you seriously do not have to be all too exact here if you cannot reach them well enough)
6. Spend the money the you would have used on ARP header bolts for two tanks of gas.

New headers need to be re-torqued after they have been heat cycled a few times. The same goes with new gaskets, especially if they are not a MLS style gasket. Even so, new MLS gaskets need to be re-torqued even if you do not hear a leak.

Use GM or aftermarket (Fel-Pro) MLS gaskets and factory hardware. Header studs suck and are not necessary.

I have had a set of MLS gaskets with 170,000 miles on them with no issues. If you have a leak with MLS gaskets, then the header flange is warped. It's not an uncommon thing for the cheaper headers to have this issue. Sometimes I take them to a belt sander to ensure they are flat. If you see uneven spots from just a quick run on the belt sander, then you need to continue further until they are flat. Sometimes a straight edge is not the best method for checking if it is not warped to extreme. Kooks and American Racing take this extra step to prevent this issue. IMO, its not a big deal and no reason to go to the more expensive header.

Stock gaskets (even used ones) and OE bolts

^This^

I'm doing heads/cam swap right now, and went with the ol' trusty OEM gaskets and OEM bolts.

I've had my headers off more time than I care to remember, but have never had any problems with the OEM stuff. I only replaced the bolts this time around because I've had them off so many times.