I'm pretty sure Maxbumpo means the tan triple line holder in the upper left corner of the picture. The current clip is broken and not holding the lines against the rubber pad on the gold anodized bracket.



Are the engine mounts in good condition?

Have you checked that you have a new style vacuum pump?

Have you checked if the crank pulley damper is wobbling at idle?

Sixto
83 300SD

Parts are on order!

However, yesterday my low coolant light came on. At idle, temps went just above the 80 mark on the dash gauge. While moving temps were normal. Is this something that would be related to the belt not spinning efficiently with the worn shock? I refilled with fresh coolant last night and came out to a puddle this morning while the car was warming up. (Admittedly, I did probably over fill a bit, so some/all of it could have been overflow).

Thoughts?

I'd figure out where your coolant leak is coming from.

Do you have a helper? With the engine cool remove the radiator cap, block the wheels, and set the parking brake. Start the car, let it idle for a bit, put the car in D, and have the helper brake torque it. Does a lot of vapor / smoke come out of the coolant tank? If so that points to a bad head gasket or head.

I doubt the belt flopping around some would cause the water pump to stop working totally.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Definitely need to spend some time finding the source of the leak today. I was running late to the office this morning so I jumped in my AMG to keep myself out of a potentially bad situation with the 350.

I can get a helper, but generally I'm solo with the tinkering.

I watched a few of your youtube videos the other day, actually. Looks like our cars are nearly twins, down to the Virginia tags! You wouldn't happen to have plans to be in VB this weekend, would you? :-D

Just saw this post. I see the piece you're talking about now, in my earlier picture.

Engine mounts are something I'd been thinking of but I'm not sure what their condition is. I know the PO had a new injection pump installed sometime somewhat recently, and that's the extent of the maintenance history that I have. I intended to have the car looked over by my old tech while I'm in VA this weekend, but I don't believe I'll be taking the 350 up.

What do I need to look for to determine which style of vacuum pump I have?

I have not looked into the crank pulley damper. I'll do some reading on it.

Pretty sure that the '91 has the bolted-cap vacuum pump as OE, the one you don't want has the lid crimped on around the perimeter, do want has several pan-head bolts holding it to the vacuum pump body.

Even with a new one, if you're in there it is a good idea to remove the pump and inspect the bearings for feel and play, and IIRC you want the later caged bearings.

Go here: http://www.w124performance.com/docs/mb/OM60X/ and click on Dave's Pierburg Pump link for more info.

__________________

Gone to the dark side

- Jeff

Thanks for this info. Same applies to the '90 like mine?

I do not know where the break-point was for the crimp-to-bolt cap, if you see the little button-head bolts you have at least the 2nd design.

Some have had problems with the bolted design also, it apparently does not mean that the bearing is the latest, nor that the bearing is in good shape. The best way to find out is to remove the pump.

"Common wisdom" here is to replace the pump every xxx,xxx miles, personally I am just as happy with the remove/inspect method on the pump as condition matters, miles are a poor predictor of failure/condition of this bearing. If the later design is installed without the proper oil-dam gasket (going from memory here) it will apparently have inadequate lubrication and fail.

__________________

Gone to the dark side

- Jeff

Thank you for this info. I will do some additional reading on this.

I put the car on ramps this afternoon to look for the coolant leak. Without pulling anything off at all I could see a stream of coolant running along a lip at the bottom of the radiator, backside. I took the clips off the fan shroud to get a better look around it, and I can't see anything that set off alarms. It looks like the coolant is coming from further up the passenger's side of the radiator, but it's heaviest and most apparent on the driver's side. Most of it pools at the very edge of the rad and empties out on to the bottom engine cover. Again, I topped the resevoir off before doing this and did run over the max fill line, so some of it could be overflow?

I ended up with this much on the driveway after a few minutes of running:




And video:

https://youtu.be/cplG6G8o0OA

https://youtu.be/gMM4MbAys0c

I've never replaced a radiator before, and I'd really prefer not to have to. I don't imagine the radiator stop leak products are highly recommended either. Any thoughts where this might be coming from?

Don't use any stop leak.

Replacing the radiator in the W126 is fairly easy. The only real worry is unhooking the auto trans cooler lines. If you remove the fan it lifts right out.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Is there any sort of way to determine if it is in fact the radiator leaking, before pulling it? Something I could do from from my driveway with ramps or jack stands?

If the '93 (W140) radiator is the same you may have mine for free, just come and get it.

__________________

Gone to the dark side

- Jeff

As far as I know W126 603 radiators are unique to the W126 603 cars.

If you've never had it out I'd say now's the time anyway. You can clean out all the gunk that accumulates between the rad and ac condenser.

One thing that comes to mind... the radiator drain valve is on the driver's side as I recall. It's a blue plastic screw.

Also, you shouldn't be using green coolant in a 603. Stick with Zerex G05, which is a light gold color or the new MB stuff which is blue.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I haven't had a chance to look at the car since Wednesday night. Is the blue plastic screw on the radiator easy enough to inspect from under the car with the engine cover removed?

Additionally, I did some more reading the other night. My idle is right at 500RPM once the engine is warm. Looks like it should be close to 650-700 or so. If I hold my foot on the pedal and bring the engine to that speed, the noise and vibrations go away. Seems like maybe the engine is just idling too low. I looked for the adjustment knob that's supposedly near the firewall on the driver's side, but I do not have one. What can I do to adjust the idle speed on this car?

Thought I might provide an update, should anyone be interested.

The car ended up leaking quite a bit of coolant last week. I called a local indy and they told me they could get an all aluminum replacement in for a pretty good price. I dropped it off at the beginning of last week and the part should be in tomorrow or Wednesday. I'm likely going to have the indy replace my tensioner pulley/arm/shock and belt at the same time.

Will report back when the car gets home.