North American Turbocoupe Organization



Exhaust down pipe to elbow connection
88 Turbo Coupe Offline
Member
#1
Hi Everyone,

I have an 88 Turbo Coupe with a large exhaust leak right behind & below the intercooler. I can feel exhaust right were the 90 degree elbow connects to the down pipe. For clarity, the other end of the elbow connects to the Turbo. Two vertical bolts hold the elbow and down pipe together.  


From the thread I found, it looks like there is no gasket for this connection. I'm looking for confirmation as my bolts seem tight. The pipe and elbow look to be in great/solid condition (the edges are smooth and uniform)  Car is stored and rust checked each year with 95k km (all stock & original parts). So if a interference fit, how can I have a leak there? 

This line is from the below thread:
 ".....and the turbo to downpipe is simply a tightened down interference fit."

https://turbotbird.com/thread-exhaust-ma...rbo+gasket
88 TC
5 Speed
Custom 2.75" stainless steel mandrel exhaust, cross drilled rotors (KVR), 245 50 ZR Eagle F1 GS-D3 (front & rear). This tire works amazing with the PRC. Wet or Dry! Lowered 1.75 inches
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Kuch Offline
Senior Member
#2
88,
Yes you are correct, there are no gaskets where the downpipe meets the elbow. It is simply cranked tight with the two vertical bolts you mentioned. I would take off the downpipe and add a little copper RTV, just a little, put it back together and see if it helps. Also, when it is all bolted down, does it feel tight, any looseness or wobble to it?
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4 50 trim, ported E6, 255LPH, Kirban, 3" DP dual 2.5" w Hooker Maxflows, MGW shifter, K&N, Gillis valve, RR cam, 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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BradM Offline
Junior Member
#3
Here's a picture that might help. I would suspect the donut gasket at the downpipe over the junction of the elbow to the turbo.


Attached Files Image(s)
   
1965 Mercury Comet Caliente; 1968 Mercury Monterey; 1969 F100 Ranger; 1987 Thunderbird Turbo Coupe
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Jeff K Offline
Administrator
#4
I put some high temp RTV (Ultra Copper if I remember correctly) on the elbow to DP joint many years ago. Zero leaks after 15+ years.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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BradM Offline
Junior Member
#5
Now I remember that there is no donut gasket at the DP for this particular Ford. Drop the DP and wire brush everything. If you see pitting, use RTV. You could also have a DP that is not properly mounted, causing the DP to not align and seat properly. Look at the catalytic converter and make sure it is mounted at the factory location (transmission).
1965 Mercury Comet Caliente; 1968 Mercury Monterey; 1969 F100 Ranger; 1987 Thunderbird Turbo Coupe
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88 Turbo Coupe Offline
Member
#6
Thanks to you all! Appreciate the quick responses!

To answer Kuch's question - it feels tight, very solid like one piece.

I have a question - should I be concerned with the bolts breaking? They are either original or replaced when Ford removed the motor to get at the very front exhaust manifold bolt that snapped off. This happened under extended warranty. So either way, the bolts have some years on them.

I will use some penetrating oil and let it soak in.
88 TC
5 Speed
Custom 2.75" stainless steel mandrel exhaust, cross drilled rotors (KVR), 245 50 ZR Eagle F1 GS-D3 (front & rear). This tire works amazing with the PRC. Wet or Dry! Lowered 1.75 inches
Reply

Kuch Offline
Senior Member
#7
I would not be concerned about them breaking, as you don't have to crank that hard on them to get a good seal. Good idea to let them soak in oil before removing them, if you can run the car a bit first to get them hot, shut off, then spray the oil on them. the heat allows the oil to soak in better. When you get it off, check for surface smoothness, if need to use a file or wire wheel to clean the mating surfaces and use a little copper rtv.
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4 50 trim, ported E6, 255LPH, Kirban, 3" DP dual 2.5" w Hooker Maxflows, MGW shifter, K&N, Gillis valve, RR cam, 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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88 Turbo Coupe Offline
Member
#8
Thanks again Kuch!

I did spay the bolts a couple days back figuring I would get to this on the weekend but did not get them hot first. I will give a turn tomorrow to see if they move easily, if not will go for a drive and spray again after. Will provide an update afterwards.
88 TC
5 Speed
Custom 2.75" stainless steel mandrel exhaust, cross drilled rotors (KVR), 245 50 ZR Eagle F1 GS-D3 (front & rear). This tire works amazing with the PRC. Wet or Dry! Lowered 1.75 inches
Reply

88 Turbo Coupe Offline
Member
#9
So the pipe felt tight at the elbow but I could move it a bit holding it from underneath the car. A bit of penetrating oil and working the nuts back and forth a few times and they became free. I noticed a silver circle around the nuts and figure that was the nut loose on the flange.

WOW these cars are built well! 33 years old and the exhaust bolts came loose with a bit of penetrating's oil and all I did was tighten the two nuts and no more leak!
Figured seeing the silver metal, I would try to tighten the nuts first and if it still leaked would then remove, sand the mating surfaces and then apply the copper RTV. Just tightening stopped the leak!

I did this from underneath with a couple of wobble extensions.

Thanks again for all of your assistance!
88 TC
5 Speed
Custom 2.75" stainless steel mandrel exhaust, cross drilled rotors (KVR), 245 50 ZR Eagle F1 GS-D3 (front & rear). This tire works amazing with the PRC. Wet or Dry! Lowered 1.75 inches
Mikey97D likes this post
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Jeff K Offline
Administrator
#10
Congrats on the easy fix!
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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