Finally...Combining TWO 1985 300D's - Page 7 - PeachParts Mercedes-Benz Forum

Diseasel300 · #91 01-19-2018, 12:08 AM

The heater works by passing engine coolant through a small "radiator" in the fan plenum. Until the engine warms up, you have no heat. Nearly all vehicles are like that, some newer ones have heat strips in the ductwork but that's an exception rather than a norm. If your engine takes a long time to reach operating temperature (>5 minutes or so to get to 60˚ on the gauge when driving), you may have a thermostat that's stuck partially open. Once the temperature gets above 60˚, you should start getting a noticeable amount of heat in the cabin.

When in heating mode - or any ventilation mode for that matter - the blower sucks air in through the grilles below the windshield and blows it into the cabin through the heater core, the A/C evaporator, and through the ductwork in the dash. When you're running the A/C (center button on the pushbutton unit), it will close a recirculation flap which shuts off outside air and draws in air from within the cabin for recirculation for better A/C efficiency.

The amount of heat in these cars is controlled by the monovalve. The climate control unit will cycle it on and off to maintain a given temperature at the heater core based on the sensed temperature of the cabin compared to the setpoint on the temperature wheel. There is no "blend door" in the plenum like most modern cars use. For the time, it was a pretty advanced system and when working properly, will maintain a very even cabin temperature. It is worth noting that there is an auxiliary coolant pump that is supposed to help with heating. If it has failed, it can cause the climate control unit to fail as well! It can also cause reduced heating at idle in some vehicles. Luckily my SDL is not one of them, I have the failed Aux pump bypassed with a brass fitting.

300Drestoration · #92 01-30-2018, 11:43 AM

ok folks, so i found the exhaust leak with my new little inspection camera. it's a full half cracked off opening..
heres a very short video.
downtubebreak.mov
and here's a picture showing where this is..
downtubebreak.jpg

After looking up things and finding part number 1234908219 (pictured below), it seems that a replacement of that would do the trick. But how difficult of a job is that going to be for me VS for the shop?

I am going to be replacing just about everything in front of it when the spring arrives. Turbo, flex pipe, and maybe even the bolted bracket thingy between the flex and this downtube section.

Lastly, would i be crazy to just wheel it into the cheap shop a block away, have them lift it so i can put a bunch of exhaust tape around it to get me through the rest of the winter? I feel like that would do the job and save my wallet since i'm already going to be doing the serious labor of replacing the rest and could tackle this section as well, no?

300Drestoration · #93 01-30-2018, 12:03 PM

UPDATE:
contacted the good quality shop around here and they would rather weld it since he says it is around the same amount of labor time.
i'm hesitant to have it welded since i feel like i should just have this whole section replaced this year. I don't believe that it would be the same amount of labor either. He tends to underquote things.
If i could just get the damn car lifted i would use a sleeve and clamps myself. I don't know if i can get under there with enough arm leverage without a full lift.

Diseasel300 · #94 01-30-2018, 06:00 PM

I guess the question boils down to what your short-term plans are. If you are planning to replace the exhaust this spring/summer and you can stand the smoke for another couple months, I'd just let it ride and do the job all at once. On the other hand, if you simply can't stand it anymore or if you're planning on doing the work later on in the year, just get it welded up and move on to bigger and more important jobs.

vwnate1 · #95 01-30-2018, 09:44 PM

Welding it shouldn't be more than $50 or so.....

If he can weld it you'd be good until Spring .

No way should you consider a a welded pipe a permanent repair .

The problem with welding exhaust pipes is ; at least 1/2 the time as soon as the torch touches the hole it grows,and GROWS, and GROWS and you get stuck ~ can't drive it anymore until it's fixed properly with a new part .

300Drestoration · #96 02-27-2018, 12:28 PM

So the downpipe needs to be replaced all together. It's cracked at the juncture where solid metal changes to flex metal. It will never be strong after welding.

I have to order a downpipe, and then when it arrives i can take it to the good shop here and he'll put it in for "around 100$" He means the best but it usually ends up that he's underestimated.

Is it possible for me to install a downpipe myself? Does one need the vehicle to be raised quite a lot for this project?

Simpler=Better · #97 02-27-2018, 03:52 PM

If you have enough lift to change oil, you have enough lift to install the exhaust. There's tons of room.

Use PB blaster when removing.

Use copper or nickel antisieze when installing.

300Drestoration · #98 02-27-2018, 09:24 PM

Quote:

Originally Posted by Simpler=Better

If you have enough lift to change oil, you have enough lift to install the exhaust. There's tons of room.

Use PB blaster when removing.

Use copper or nickel antisieze when installing.

Well, i did an oil change flat on the ground easily. So, not sure how the relates to a downpipe. Probably need to lift it some?

vwnate1 · #99 03-01-2018, 01:01 PM

" Is it possible for me to install a downpipe myself? Does one need the vehicle to be raised quite a lot for this project? "

IIRC you're in salt country so maybe, maybe not .

I'd give it a go but then I like challenges and have had tools in my (greasy) hands since I was 4 or 5 Y.O. .

300Drestoration · #**100** 03-01-2018, 01:05 PM

Quote:

Originally Posted by vwnate1

" Is it possible for me to install a downpipe myself? Does one need the vehicle to be raised quite a lot for this project? "

IIRC you're in salt country so maybe, maybe not .

I'd give it a go but then I like challenges and have had tools in my (greasy) hands since I was 4 or 5 Y.O. .

That's enough for me to hear to toss the project into the shop. He seems to think it's simple for them.

Yep i'm in NY. But what does that have to do with me trying to replace downpipe? Getting salt all over me?

vwnate1 · #**101** 03-01-2018, 01:18 PM

No ;

Heat and corrosion make exhaust works the very worst of all .

I grew up Down East and hated the endless, myriad broken bolts etc. that can halt you dead unless you're in a well equipped shop .

300Drestoration · #**102** 03-13-2018, 10:31 PM

I'm finally ordering the downpipe, which will be installed by the good spot in town.
Are there any relavant o-rings / seals required for re-making the connections to either the top/front end of it or the tail end of it going down under ?

I couldn't find any info pertaining to this on any parts sites...

Diseasel300 · #**103** 03-14-2018, 12:08 AM

There is a sort of gasket that goes from the downpipe to the rest of the exhaust system. Pelican shows it on their parts list:

https://www.pelicanparts.com/More_Info/2024920181.htm?pn=202-492-01-81-M183&SVSVSI=3304#

Not sure about the top end coming off the turbo, the W126 has a bellows there with no gasket, just a clamp.

*EDIT*: Pelican shows another gasket: https://www.pelicanparts.com/More_Info/1074921409.htm?pn=107-492-14-09-M183&SVSVSI=3304#

Hope that helps a little bit!

vwnate1 · #**104** 03-14-2018, 09:31 AM

The gaskets, special bolts and myriad other little things are what makes or breaks a proper repair and you're wise to ask .

Best bet is to copy and save one of the many different Electronic Parts Catalog links offered here and always take some time to search and look closely at the diagrams as they'll show you those little parts and give the correct part numbers too .

Often the Enthusiast DIY'er has no idea they might need something until the job is 1/2 done .

300Drestoration · #**105** 03-14-2018, 07:39 PM

All right i'm confused.
The downpipe part# is 1234908219 which i ordered the improved ANSA version of which i'm not going to doubt about being correct. Done deal i think. It's their own proprietary part number but whatever, everyone says it's way better than the OEM.

I also ordered 202-492-01-81 to connect the bottom of downpipes to center exhaust pipe...

....But some people show this part as a rubber ring https://www.ecklersmbzparts.com/mercedes-seal-ring-22439.html and some people show it as a substantially chunky metal ring.

This diagram here has no appearances of metal rings, and shows just the one rubber ring at the bottom connection. https://www.ecklersmbzparts.com/diagram/view/index/id/156

But then you discover that there might be a part that connects to the top of the downpipe as well, 107-492-14-09
, which here at pelican you can see looks identical to the one at the bottom of the downpipes https://www.pelicanparts.com/catalog/SuperCat/3306/MBZ_3306_EXHPIP_pg1.htm shows them both next to each other. Clearly pelican thinks there are two rings, and they are both metal.

So, are there rubber rings involved? Or not? And do i need two? And do i actually need two metal rings AND two rubbers rings?? Sigh. Pelican shows no rubber ring at all!! And why are we sharing part numbers ?? Part numbers are not for sharing !!!

What would you guys do?