Heat Exchanger to Crossover Exhaust Line Gasket Replacement

[hcalvani]

Hi Folks,

For my stock '88 930 (w/ 56k miles), I found an exhaust leak at the interface/gasket on the driver side (1-2-3) heat exchanger and crossover pipe (i.e, exhaust line). One can easily observe the fumes emerging from the interface/gasket area while the car is idling (note that the cross-over pipe and heat exchanger are in good shape - that is, no significant rust etc.)

I went ahead and purchased the Porsche layer metal gasket (part # 930.111.192.06) and the associated factory bolts (900.074.282.02) and nuts (900.910.097-0C) from the dealership.

I was initially planning on replacing the gasket myself, but I am having second thoughts given the (perhaps) more challenging aspect of performing this work w/o a lift, and also given the potentially expected problems removing the original bolts. My approach is to saturate the area with WD-40 and let it sit overnight before attempting bolt/nut removal.

Can folks that have performed this repair (DIY) comment on things to watch out for and provide some recommendations?

Also, I assume that I will also need to remove the cross-over pipe altogether - which in this case, I should also replace the gasket/bolts/nuts on the other end of the cross-over pipe?

Any feedback/guidance would be greatly appreciated!

Thanks in advance and happy Porsche motoring!

Humberto-

[RarlyL8]

No need to lift the car, just jack the engine up enough to give you room to work.
No need to remove the crossover pipe, just pry it apart with a screwdriver and slip the new gasket in.
Yes soak the bolts with kroil or liquid wrench overnight. There are 6 bolts in that tight area, I would change both gaskets and all 6 bolts while you are in there. If the bolts are severely rusted break them off and punch out the remaining studs or use a torch.

[kjchristopher]

Kroil is the dogs ballocks.

https://www.amazon.com/Kano-AeroKroil-Kroil-Penetrating-Aerosol/dp/B005ESIHZI/ref=sr_1_1_sspa?ie=UTF8&qid=1505526760&sr=8-1-spons&keywords=kroil+penetrating+oil&psc=1

[hcalvani]

RarlyL8a and kjchristopher, thanks very much for the feedback!

I ordered the kroil oil as it appears to have an excellent effectiveness record.

When installing the gaskets, do you recommend lubricating them with silicon-based sealant-type products? I have seeing very good reviews for Permatex.

Thanks again!

Best,

Humberto-

[Strygaldwir]

I love Kroil, but did not have much success when removing most of my exhaust bolts and studs. Since all the connectors holding the cross over pipe are bolts, there is not too much worry if you just shear them off. As suggested, just change all the bolts.

I did have more success with heat on the studs. Just heated them cherry red and was able to get them out. But, not applicable here.

Cheers and good luck.

Keith

[hcalvani]

Thanks for the feedback, Keith.

Cheers,

Humberto

[hcalvani]

Hi Folks,

For the record, can someone please comment if the gasket needs to be lubricated w/ a silicon based product (or any other compound for that matter) prior to installation, to mitigate gasket leaks and long-term gasket deterioration?

Thanks in advance,

Humberto-

[Strygaldwir]

I never put silicone on them, I'd think the temperature is too high. I did however put a light coat of anti-seize on all the metal exhaust gaskets.

[hcalvani]

Hi Folks,

Thanks for the feedback on this topic.

To bring the topic to closure and also towards the benefit of other members, can someone please recommend an anti-seize compound to use before installing the gaskets?

If using the Permatex anti-seize lubricant, is the nickel-based version the correct one for this application (i.e., metal based gaskets, in a relatively high temperature environment)?

Is it best to just use the Optimoly TA product that Porsche uses?

Thanks in advance,

Humberto-

[flightlead404]

Originally Posted by hcalvani

Hi Folks,

Thanks for the feedback on this topic.

To bring the topic to closure and also towards the benefit of other members, can someone please recommend an anti-seize compound to use before installing the gaskets?

If using the Permatex anti-seize lubricant, is the nickel-based version the correct one for this application (i.e., metal based gaskets, in a relatively high temperature environment)?

Is it best to just use the Optimoly TA product that Porsche uses?

Thanks in advance,

Humberto-

I use a pure copper product and silicon bronze nuts