Heat exchanger issue

[Targatogo]

Hi - my heat exchanger has a small movement between the body and the pipes that leave it - should that be the case? On accelerating there is a burbling noise as if exhaust leak. Is this where it could be coming from? When running a constant speed there is no burbling noise!

[75 911s]

There should be no movement. The HE should be rock solid tight to the engine. Can you post a video on youtube and link to here of the movement? The gurgling could definitely be an exhaust leak.

[DRACO A5OG]

OP, it sounds like you have an exhaust leak, +1 post a video or pictures.

[Targatogo]

Hi - link is https://youtu.be/98fRdVVy-BM

You can see the body of the heat exchanger moving up and down the inlet tube. The exchanger tube is secure to the engine as I have checked all the nuts.

Thanks for you help......

[Targatogo]

Hi - posted here https://youtu.be/98fRdVVy-BM
Not great quality but you can see what is happening.

[cabmandone]

What year is your car?

[Targatogo]

1982 - I have posted a video, just waiting for the mod to clear it......

[cabmandone]

Okay. You can have some movement in the metal on the H.E's but that would be a tinny rattling sound. In some cases an off exhaust note can indicate a broken head stud. Does it make the noise more under heavy acceleration?

[Targatogo]

Yes - more noise under acceleration. Can't hear much when running at a constant speed. Engine was rebuilt 30 months ago and new heat exchangers installed.

[Flat6pac]

Sound of head studs loose or broken because the 82 uses inserts into the heads so exhaust leaks aren’t like burned out exhaust gaskets of the thin flange heat boxes.
Bruce

[Targatogo]

How easy is it to check the studs?

[cabmandone]

Originally Posted by Targatogo

How easy is it to check the studs?

Take your lower valve covers off and you'll be able to see the usual suspects. If the engine was rebuilt I doubt it's broken studs since they most likely would have been replaced.
If you're still using a 2 out 1 in exhaust I'd suggest checking all the joints and verify the exhaust barrel nuts are torqued appropriately.
If you can get the car up on a lift or on some jack stands, I'd get under it and look for any carbon deposits from a leak. If you've put any miles on the car, it should be pretty evident where the leak is.

[Targatogo]

Ok - thanks for your advice. Something to get my teeth into during the week.

[cabmandone]

OOPS! I meant two H.E's into a single point on the muffler, not two pipes out from the muffler. This is why I shouldn't post until after my second cup of coffee. Good luck! I hope you track it down.

[Targatogo]

Have a look at the issue...https://youtu.be/98fRdVVy-BM

[cabmandone]

HOLY SMOKES that's a lot of movement! The old rusty pair of H.E's I had didn't have that much play in them.

[Targatogo]

I know - the other side is rock tight. The rusty one I have in the garage is rock tight too. So .... is that the cause of the exhaust blow rather than a broken stud?

[DRACO A5OG]

The stainless steel shroud does not get any exhaust, it just radiates and keeps heat from the pipe in so when you open the heater flaps it can blow in hot air to the cab.

Most likely the weld that held the HE in place broker off and taking pipe material with it.

Search for a good used one. Block off outlet and pour water into it, if it does not leak you will be good to go.

Sorry time to remove HS and replace. Make sure you get new nuts and gaskets, Might as well do both gaskets and inspect the other side for rust too.

[cabmandone]

Originally Posted by Targatogo

I know - the other side is rock tight. The rusty one I have in the garage is rock tight too. So .... is that the cause of the exhaust blow rather than a broken stud?

I'm wondering if what you're hearing isn't a rattle. That shroud should never have exhaust gas in it since it's what delivers heat to the cab. Take a few finish nails for wood trim and place them between the exhaust ports and the shield just to hold the shield tight and then go drive it. I would find it hard to believe you have a head stud issue unless the original studs were used rather than replacing. Could still have a bad exhaust doughnut somewhere but I'd start by temporarily getting the shroud tight and see if the noise goes away.

[Targatogo]

Ok - tomorrow I will tighten it up with some exhaust putty and then go for a run to see what happens then. It could be that the HE is rubbing up and down on the pipe and making a noise (there is some noise in the video when I was moving it up and down). Be annoyed if I had to replace as this one was fitted new 30 months ago! Once again, thanks for your comments and advice. I will update asap.