95 E320 M104 What pump is this?

[HCH]

The pump is on the passenger side of the engine just below the exhaust manifold. It is on the front of the engine and is driven by the poly/multi belt.

It has a U shaped hose that points down and is open (air intake?) and another hose with a valve/thermostat on the back of it.

I think it's the air injection pump.

The car wouldn't start and I kept cranking it. It eventually did start and promptly started smoking under the hood. Switched it off, popped the hood and observed a smoking belt/pulley combo on said pump. The pulley was tilted to one side. Not sure if it was the belt (which is 5000 miles old) that was smoking or the pump or both.

Would it make sense that the car wouldn't start if the pump was failing? Or perhaps it was putting enough resistance on the belt to mess things up?

Your suggestions and advice are my happiness. Particularly along the DIY angle.

Thank you!

EDIT: I'm almost certain it's the air pump. A remanufactured one is about $200 on ebay. Has anyone here replaced one before? How much stuff has to be moved to get to it?

[engatwork]

Good diy'er type of job to replace which it sounds like yours needs. Did you watch it while it was running/smoking to ascertain where the smoke was originating? Sounds to me like you have a bearing gone bad. This type of stuff happens and it is usually based on mileage. How many miles are on the car? Keep in mind that if someone were to install a new belt and it was too tight then it will cause premature bearing failure.

[HCH]

155000 miles almost exclusively highway. Well maintained and drives like new (at least to me).

I didn't get a clean look at exactly where the smoke was coming from. There was no squealing or other unusual noises. The belt doesn't look any worse from it. I kind of figured when the new one went on that it was going to tweak anything that was on the edge.

I'm a pretty competent DIYer but don't want to have to pull too many things to get to some hidden bolt on the unit. Haven't we all said "looks like just 2 little bolts and it comes right out" only to have it take half the day?

But the car is in front of the house so that means paying the tow truck + $500 for the pump + $88 hour in the shop. It's not running anyhow so I think I'll take a crack at it with the $200 ebay pump.

Any mechanics out there who would advise otherwise?

[A264172]

http://home.comcast.net/~martin.carney/14-7251.pdf
Hope this helps.

[HCH]

That helps quite a bit, thank you!

So assuming that removing the viscous fan clutch isn't a problem (prerequisite) I should be good to go. Another post said this about the belt:

"On the 94 & later cars the tensioner has a built-in spring & that keeps the tension at pre-set amount. There is a place on tensioner to place socket & move tensioner to release tension on belt. Very simular to "American" style tensioners."

So how hard could that be?

I need to get that repair CD. I bought one on ebay but it turned out to be a fairly generic and very useless Mitchell repair guide.

[A264172]

Viscous fan clutch thread:
Fan Clutch
Viscous fan clutch:
http://home.comcast.net/~martin.carney/20-3120.pdf
Fan shroud:
http://home.comcast.net/~martin.carney/20-3400.pdf
That may not at all be necessary though. Best to loosen belt at tensioner and see if you can work around the fan. Just pay close attention to belt routing or leave it mostly on other pulleys as it may not be intuitive.

[HCH]

Excellent! Many thanks.

[HCH]

EDIT: On this later M104 engine you just put a 15 mm socket on the tensioner pulley and turn clockwise. Tension is released both from belt and owner. Remove fan shroud first.

Tensioner Belt discussion was here:here.
----

I've finally gotten around to doing this. Problem now is loosening the belt via the tensioner. I've read all the posts I could find and cannot for the life of me relate what I've read to what I see in my engine.

The fan shroud is pulled.

Re: other threads: I don't see any nuts that are pointing up, I see no keyed allen bolt on a pulley. None of the pulleys are 19 mm hex heads.

This is a very late 95 E320 (May 95) engine # 12 090072

Pulley Diagram mine is the lower right.

Atop the tensioning pulley is nothing much. A combination bracket basically. It DOES NOT look like this:

Tensioner

Another post mentions just tightening the tensioner pulley bolt until it moves in, but that's on a 96 104.

I think I'm missing something basic - it's been hours of staring at the engine and checking posts here. I'm not a total idiot (usually).

Any help with this tensioner setup would be grand.

[HCH]

To follow up:

Installed a rebuilt pump. You do NOT have to remove the fan/clutch to get the pump in and out. It's a bit of a tight fit and the fan blades have to flex some to let the pump by. If you have the tools for the job be sure to remove the fan as it will make things a lot easier and you won't risk damaging the fan.

If it's not obvious already you will need a decent socket set with a selection of extenders. I just barely had the right combos.

Working the bottom bolt on the pump is not that hard. Just feel for it.

The check valve should be tested. I didn't do this.

Since the belt had a burn spot from the frozen pulley I purchased a new one. Got a Napa auto parts one and I just could not get it on no matter what. It's fairly cold out which could have affected its stretch. I don't know but I suspect since it was a stocked part it is more universal in nature and isn't quite to spec.

Put the old belt back on and will have the shop replace it if I have to.

That's it for the technical part, now I get to complain about the logistical aspects.

The independent shop wanted $600 for a rebuilt pump + labor. Call it $800 total by the time I'm outta there. Car was in front of my house so I would have had to pay $150 for towing to the shop. $950. No way.

Junk yard wanted $275 for a pull. They had 2 e320 hulks on the yard, one with 84,000 miles and the other with 155,000 miles. They didn't know which one it came out of (really?). A rebuilt one is available from many local suppliers for $50 more but they wouldn't budge on their price. Clueless.

Rebuilt one on ebay was $220 or $190 if I had had time to bid instead of buy it now. Shiny and nice.

That's my story. Thanks for all the forum help you just saved me $700!