Hi all, just wondering what the silver flexible tube or hose that runs from the front to the rear or my engine compartment by the alternator and oil filter. I noticed it's broken and I am not sure if I should be driving it until I get it fixed. Thanks in advance, Franco79 '79 245dl 217k

Mine had rot/holes in it. I fixed the damage with aluminum tape, the 2" wide
stuff aka furnace duct tape - sticks very well to the metal tubing.
Hopefully yours is salvagable.

I believe your talking aboutt EGR, or Exaust Gas Recirculator. It does what the other posts have said about heating the incoming air. Mine has a decent gap in it and no problems for me so far. Just my 2 cents.

Mines off and I'm lovin' it!!!
--
Simon 80 240 285k 17 years.

Unless you need to fake the Orwellian emmisions gestapo, dump it. If you have F/I, you are inviting a fried AMM.
--
D.P. Mulvey in Central VA.

In some states that preheat tube is an emission test check item, so no tube = no pass.

Inside the air filter box is a big flap valve that is supposed to close off the inlet from the preheat tube and open the inlet from the front air. In your case, there may be no difference either way.

In cars with an Air Mass Meter, when the air box valve controllng thermostat ($35 item, new) fails, and the AMM gets only heated air, the AMM gets fried, ($100+ item, used) so it's a bigger deal for 1983 and newer bricks.

Older is so much simpler, sometimes.

Good Luck,

Bob

:>)

I think that it's called a "pre-heat" hose. It takes warm air conducted off of the exaust manifold and sends it to the air filter box. It's supposed to help warm cars up in cold climates. It also helps emissions. Mines been missing since I owned my car and never got around to replacing it, but it's always passed emissions w/out it. The weather here is pretty warm, so I'm not sure if I need the hose? Maybe someone will recommend it to me.
--
Michael 'Street'... one AZ '85 244DL 191K miles

Here in the UK, emission tests are always done with the engine fully warm, so the pre-heat tube from the heat stove on the manifold to the air filter box doesn't come into the equation. It is meant to aid cold starting by supplying warmer air at the start or when the manifold warms up which is pretty quick, but when the engine bay reaches a certain temperature, can't remember what temp, it's redundant. Just make sure the valve in the air filter box closes it off when it should, if you are going to use it.
--
'86 740 GLT 2.3 injection 7 seater estate, '89 740 SE 2.0 injection saloon, '87 BMW 316 carb Coupe