During reinstall of a freshly rebuilt motor we discovered one of bolt flanges (also called dog ears?) on the driver's side heat exchange was cracked at the weld. We decided to proceed with installing knowing that I would need to get it addressed soon. Well ... that flange completely broke off when mounting it.

I have no experience welding nor do I own the welding equipment - my question is can that be welded back on good as new ... or do I have to replace the exchanger?

The heat exchanger is in great shape with no signs of rust or leaks anywhere. So it would be great if I can have it welded vs. needing to replace.

Thanks in advance.

It all depends on how solid the steel really is and the talent of the welder.

I had to do a light weld like that on an old victorian chair wheel caster not long ago. So easy and strong. I have a super cheap 120v Rosin welder from harbor freight (titanium). I also used the same welder on a quarter inch leaf spring hanger and it was more than up to the job. Well worth the 150 dollars

I did weld professionally in a previous life but in my opinion anyone could do the same with that welder.

You didn’t say if you were using stainless steel exchangers, I recently found I had cracked ears on two pipes. I practiced a bit tig welding a couple of stainless bolts, when I felt confident enough I had at it.
I am no where near a pro but I find joining metal together very satisfying. Find a good local welder, they will have the experience to let you know what can be done.

I have had the same issue, in my opinion the heat induced into this area changes the metal (steel or stainless) and does not weld properly. A metallurgist may have more information.

I don't believe they are stainless, BUT ... the gray paint is scratching off and it's shiny silver underneath. Almost looks like the PO painted over stainless.

Was that ever a thing or did older stainless heat exchangers come with gray paint on them?

Can you find a small metal shop nearby? When I was working in a little cnc shop we would always weld stuff up like that for people. No charge. But that was Minnesota. And we did tons of stainless stuff (food grade).

That was going to be my next move if folks think this can be repaired (instead of needing to be replaced).

I was hoping to hear that other folks have been successful in making this repair and that it's enduring (i.e., didn't break again or cause issues like fitment).

My stainless steel set had 3 cracked ones. I had the local welding teacher from the community College in Frederick TIG them up.

Magnet test?

Sharing an update on my repair process so that others don't make the same mistakes ...

I found a metal shop nearby that would TIG weld all 4 ears on my drivers side 2.0 HE for $95 (it's the hourly rate and their minimum). 1 dog ear was completely broken off, 2 were still attached but starting to separate from the HE, and the 4th ear was fine but they wanted to reinforce to prevent it from tearing in the future.

I picked up the HE a couple of days later and got under the car to mount it. Problem: the dog ears weren't lining up with the head studs. They must have shifted a hair when they were re-welded. I instantly wanted to kick myself for not dropping off an old head with the HE.

FIRST LESSON LEARNED: when taking a HE to have the dog ears re-welded, take an old cylinder head with you so that they re-weld the dog ears to line up with the studs.

So I took the HE back to the shop w/ an old head. I was told that my heads were identical (same castings - that the only difference was the PS had the head temp sensor hole) and that it didn't matter which head I took them. They said they wouldn't charge me since the mistake was on their end not putting the dog ears exactly where they needed to go (but how could they know w/o having an old head)?

I waited in the shop lobby while they re-welded HE for the second time. I got the HE home and got under the car to mount it and the dog ears were still not lining up with the studs. They were actually more off than the first time. However, it fit on the old cylinder head I took them (which was a PS head).

SECOND LESSON LEARNED: when taking a HE to have the dog ears re-welded, take an old cylinder head from the same side as the HE with you and make sure it's the right side head for the HE.

Just dropped the HE off at the metal shop for the 3rd time (I'm sure they're going to charge me this time). I'm learning lessons the hard way.

Thought I'd share so that others don't have to endure the same humiliation, waste of time, and expenses.

Refrain from fully torqueing the nuts right off the bat when installing. Increasing the torque value to cure an exhaust leak is a bad idea. Inspect the ear welds BEFORE installing.

Makes sense. Thank you.

For the record, the torn HE dog ears were inherited from the PO. The only thing I did (with the help from kind, generous, fellow 914 owner) was drop the motor and trans to send off for rebuilding. We noticed the torn dog ears when the HEs were off the car.


I will keep your guidance in mind when I get the HE back.

What is the correct torque for the HE flange nuts?

So sorry you are learning this in this way.

Hope the third time is a charm

My saga continues on this damn HE.

The dog ears line up with the head studs now, but … the dog ears are too high up on the pipe and there’s a small but present gap at the top of the pipe where it should meet the washer and head which is obvi going to be an exhaust leak.

I’ve never cursed so loud.

I’m done with trying to have these dog ears re-welded. Need to find a nice used or new HE. Should have done that from the start. Would have saved me $200 at the welder, lots of time, energy, and a ton of gas going back and forth to the welder.

Anybody have a 2.0 driver’s side HE laying around they can part with?

Can you just grind down the ear. You will have less clamping area, but these don't need 35 ft/lbs to install. The reason they were broken in the first place was due to overtightening.

Damn. That’s a great idea.

I would consider trying that, but I’m also noticing that now one of the two pipes on the HE is not a perfect oval (looks bent) so it won’t mate with the oval head port and copper washer … that is also going to cause problems. That must have happened on one of their re-weld attempts.

Man … I’m cursed on this attempt to repair rather than replace the HE.