North American Turbocoupe Organization



Loosening turbo exhaust bolts....
Kuch Offline
Senior Member
#1
I had an issue earlier this summer with my 5 bolt exhaust flange coming loose from the turbo causing an exhaust leak, 2 of the 5 bolts were missing and others were loose. A little background, I have a turbo blanket installed , a 3" downpipe, and a T3/T4 turbo, so this is not stock. I replaced the stock bolts that were installed with new ones slightly longer so I could install lock washers also. Everything went together nicely and has been nice until yesterday when I noticed a leak again, with one bolt all the way out sitting in the blanket. I'm not sure why these are coming loose, should I use loctite even on the hot exhaust manifold? I would love to safety wire them but finding drilled bolts or drilling my own would be super tedious with my tools. Any ideas?
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4, ported E6, 255LPH, Kirban, Stinger Exhaust, MGW shifter, K&N, Gillis valve, BP1.5, PIMPx, Koni's
1964 Ford Galaxie 500XL, 390 6V, Big Solid cam, Headers,3.89's, 4 Speed, Vast and fast
1960 Ford Starliner, 292 Y Block, 312 4bbl intake, headers, 3 Speed, slow and low
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hast2307 Offline
Junior Member
#2
My brother and I had similar issues with our SVO's but it was the turbo to exhaust manifold stud coming loose. I saw car show that was having a similar issue with bolts and nuts coming loose and they used Nord-Lock's to fix the issue. When we went to a flange nut and Nord-Lock that cured our issue and I also used them on the 5 bolt flange again using a flange style bolt to provide more clamping and holding power.
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Mikey97D Offline
Senior Member
#3
Loctite will not work at those temperatures seen by the exhaust that close to the motor/turbo.

The bolts you have been using are expanding and contracting at a different rate that the flange. Change the material of the bolt from what you currently use. Search what material bolt either originally came on our cars or what others are using. Otherwise safety wiring is the only other option.
1988 TC, 5 spd, Stinger 3" Exhaust, Schneider Roller Cam, -4° Cam Pulley, Cone Filter, Gilles Boost Control Valve set at 17 psi, Walbro 255 lph, CHE Rear Lower and Upper Control Arms, Braided Brake Lines, Hawk HPS 5.0 Front and HPS (F) Rear, CRES Inserts in front calipers, and '93 Cobra Wheels with General 235/50R17 Tires.   
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anasazi4st Offline
Senior Member
#4
Mikey97D:

I had the same problem, I did research as I too believed that red threadlocker would not work at those temps. Surprisingly I found several forums where members claimed that it would work and that they have been doing that for some time. I installed new bolts and put red threadlocker on them, so I guess we will see.

I have been perplexed by lots of vibration from about 55-70 mph, the rear view mirror shakes so badly that the headlights behind me are a moving blur. I used an unlabeled release bearing and it started making noise right after installation, so in the process of removing the exhaust pipe I saw the loosened turbo bolts. I also saw all the Driveshaft bolts (at the rear axle) were loose—one was missing. There’s the source of the vibration.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 3 T5OD full rebuilds, 6 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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Mikey97D Offline
Senior Member
#5
(10-12-2023, 11:48 PM)anasazi4st Wrote: Mikey97D:

I had the same problem, I did research as I too believed that red threadlocker would not work at those temps. Surprisingly I found several forums where members claimed that it would work and that they have been doing that for some time. I installed new bolts and put red threadlocker on them, so I guess we will see.

I have been perplexed by lots of vibration from about 55-70 mph, the rear view mirror shakes so badly that the headlights behind me are a moving blur. I used an unlabeled release bearing and it started making noise right after installation, so in the process of removing the exhaust pipe I saw the loosened turbo bolts. I also saw all the Driveshaft bolts (at the rear axle) were loose—one was missing. There’s the source of the vibration.

Red Loctite is a very broad selection of Loctites.

If I was going to chance using Loctite it would be a temperature resistant Loctite 242 threadlocker or similar.  Or I would maybe try a cylindrical locker like 680 or 635.  Material prep is very important for Loctite or any anerobic thread locker where you want to use alcohol to remove the grease and etc.   I would avoid using acetone since it does leave a little residue (funny thing one of the Loctite Primers uses it as an ingredient).

I would still use a different material bolt.
1988 TC, 5 spd, Stinger 3" Exhaust, Schneider Roller Cam, -4° Cam Pulley, Cone Filter, Gilles Boost Control Valve set at 17 psi, Walbro 255 lph, CHE Rear Lower and Upper Control Arms, Braided Brake Lines, Hawk HPS 5.0 Front and HPS (F) Rear, CRES Inserts in front calipers, and '93 Cobra Wheels with General 235/50R17 Tires.   
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anasazi4st Offline
Senior Member
#6
(10-12-2023, 11:48 PM)anasazi4st Wrote: Mikey97D:

I had the same problem, I did research as I too believed that red threadlocker would not work at those temps. Surprisingly I found several forums where members claimed that it would work and that they have been doing that for some time. I installed new bolts and put red threadlocker on them, so I guess we will see.

I have been perplexed by lots of vibration from about 55-70 mph, the rear view mirror shakes so badly that the headlights behind me are a moving blur. I used an unlabeled release bearing and it started making noise right after installation, so in the process of removing the exhaust pipe I saw the loosened turbo bolts. I also saw all the Driveshaft bolts (at the rear axle) were loose—one was missing. There’s the source of the vibration.

I just installed a new (to me) T5OD that I successfully rebuilt using a Craigslist one I purchased on the West side of Phoenix for $150 (!!). There was a catch: no input shaft or its hardware (spacers, shims), and no front bearing retainer. I got an input shaft from eBay; new Timken bearing and race; the rest I already had from a Mustang T5OD I got about 10 years ago. (This is the 4th T5OD that I have rebuilt.)

I was very fortunate: the inside was almost brand new—a sticker on the case said it was rebuilt and under warranty, but the date is worn off. New(er) barely worn shift fork pads, bearings and races (also hardly worn), minimal wear on the fiber clutch rings. I purchased a premium Rebuild Kit for last year’s work, and had replaced good serviceable parts then with ones from that Kit. Those were now put back into service. I did get all new Timken bearings and races, except for the front countershaft one and its bearing cup, both of which showed minimal wear. (The cup has a sealing o-ring attached that can be tricky to install.) All the others were probably okay as well, but bearings rarely wear out if cared for properly—and they are inexpensive.

I only put 6000 miles on that one before swapping it with this unit. Replacing a transmission is not on the top of my favorite things to do with my TC—I actually think swapping engines is probably less work, but I will let you know that when I get the replacement one rebuilt and put it in next year. The reason for this project was, as I mentioned in a previous post, a noisy clutch release bearing and a lot of vibration above 55 mph.

The release bearing was unbranded and part of a clutch kit—at the time I thought it was likely a bad idea to use it, but the NOS Motorcraft one I got from eBay spun unevenly—the grease seemed to have mostly dried out. The unbranded one seemed to be a better idea. I’ve since learned that the National branded one that I researched—614014—is, according to several forums I read, the same one that Ford used for its Motorsports line. (You have to be right on this, else it’s pull everything apart and replace it.)

Fortunately the pilot bearing was still intact (never saw that before!), so no removal of the bellhousing and clutch assembly was required. I removed the old bearing just fine, but had to remove the pressure plate/release bearing fork to install the new one, and getting that thing back on isn’t any fun either.

As Mikey97D suggested, I used high temp Red Threadlocker on the turbo exhaust flange plate, and replaced the remaining two bolts with 10.9 grade ones. I replaced the driveshaft bolts with Dorman ones that already had a red thread locker on them. Inspecting the old ones, I noticed the threads in the middle were worn down. Good call to replace them.

In the end I was very pleased. Smooth clean crisp shifting. No more noise or vibration—after about 15 minutes the old release bearing was swish-swish-swishing. I got on the 202 Loop and drove for 53 miles! This is the best it has driven in 20-some years or more. There was always something —poor engine alignment due to driveshaft coming apart, leading to poor clutch operation and shifting (fixed with two 1/4” bar stock pieces bolted on as braces, for support); sub-average charging issues; leaking transmission (??); etc.

I like things to be a certain way, and I can usually find things that I either need to try and fix, or overlook. For this drive I was enjoying everything working properly, for what seemed in a while.

Next on the Project List is a new replacement for the used left window motor I installed a couple of years ago when the old one quit. While getting that done I will also replace the rubber weatherstripping on the upper door and inner door panel with some NOS that I got from eBay a while back. (I’ve already completed the right side when I replaced that window motor a couple of months ago, when it too quit working).

Hopefully that’s it for a while.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 3 T5OD full rebuilds, 6 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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