W115 220/8 Coolant, Radiator, and a Leak.

[Coastal220]

Hi All,

So I have a couple of questions here relating to my radiator and a coolant leak. The leak is worrisome.

1) How does the inside of my radiator look? Does the deposit buildup seem normal for a radiator of this age? I notice some little white chucks about 2mm in diameter inside. And I know this is a much discussed issue, but what type of coolant should I be using here? I only acquired the car about 6 months ago, and it appears to be the usual neon green stuff, I can't be more specific than that.

2) Coolant seems to be spilling out the hole in the picture (see red arrow) right from the base where the fan is mounted to the engine. What would this suggest--do I need to do some troubleshooting or does this indicate a particular problem? It does not seem to be a huge leak, yet, but it is concerning.

Any and all details, especially about the leak, would be so appreciated.

Thanks,

Trevor

[Frank Reiner]

Trevor:

The leak you have indicated is from the water pump; the seal is failing.
The fix is to replace the pump. For most of us mortals the seal is not field serviceable; the pump is not expensive.

The white chunks I have seen in any number of vehicles of all makes.
The coolant (as with all coolants) will continue to provide temperature protection almost indefinately; the anti-corrosion properties degrade in 2-3 years.

Before you change the pump, use an off-the-shelf cooling system cleaner, and throughly rinse the system (3-4 changes of rinse water).

[Coastal220]

Frank,

Thanks for this, I'm glad to know it's just the pump.

Do you recommend the cooling system be cleaned by running the engine up to normal operating temperature before draining each flush?

You have to let me know how the winter resurrection goes in your shop sometime--I haven't forgotten about the upgrade but like you I'm in no rush.

Cheers.

[dirtyharry]

Geez Trevor, you seem to be having a really hard time with this 115, blow-by, carb issues, coolant leaks, was this thing neglected or what.... I guess I'd be really frustrated with it by this point. I hate dumping money into cars you can barely enjoy because your worried about breaking down the next time you drive it. although I dumped a lot of money into my W108, and it left me stranded one day this past march, I actually had to sleep in it. Here is my 114 below.. It has a flat... this picture was taken today.. you can see all the salt and cold here in MN

[Coastal220]

Hahaha, the car is actually a bit of a gem, I think--every mechanic that looks at the thing tells me what unusually good condition it is in--and this is in the Bay Area where there are a lot of nice older Mercedes.

The blow-by issue was posted by a different member here in the forum, and the carb issue was just my the fuel shutoff solenoid having a bad connection. Overall I really like the car and I don't think it's been abused at all--it's very tight all around.

I will admit: I am a furniture maker who is pretty fastidious about the fit, appearance, and condition of things, so I tend to notice small things and fret over them. Which means the car gets a lot of attention if only for issues that might not always require it. Though I am not a mechanic of the sort many of these guys are... The water pump of course is truly necessary replacement.

I'm glad to be in good, knowledgeable company with everyone here.

[Coastal220]

And sorry to see the flat and cold! Though I do miss the snow--not in situations like that, of course.

[dirtyharry]

the flat's not a problem.. I'm just too lazy to air it up. it has a slow leak... sorry for the mix up... its kinda hard to keep people's car problems all separate especially when its all so similar.. maybe I'm just tired, we are 2hrs ahead of the coast here in the Midwest..

but its good that you pay attention to the little things even if they aren't necessarily broken.. preventative maintenance really goes a long way...

[Frank Reiner]

Trevor:

Re: Cooling system cleaning
Do bring the system up to temp with the cleaner in it, drive it around for 15-20 min. When subsequently rinsing the system, it will help to get it warm enough that the thermostat opens and you can see circulation in the top tank before each draining.

[Coastal220]

Sounds good on the flushing. Does anyone have recommendations on what to use on these old radiators--aluminum friendly?

[Palolo]

Old radiators are aluminum- (and plastic-) free.

You'll have aluminum in other parts of the engine, but flushing with mild acids to help dissolve some of the scale (alkali/lime/mineral buildup) is safe enough, since you would be doing at least one or two pure water flushes afterwards to neutralize the acid flush.

You can use citric acid (available in powder form from farm stores, seed suppliers, health food stores, etc) others have used vinegar (large jugs from Costco) or other diluted acids. The common theme is that the acid breaks down the scale. Like using lime-a-way in a kettle.

A garden hose popped in to the top radiator hose (wrap duct tape around the hose to build up a "plug" to fit) is easily strong enough to reverse the flow of coolant for a "back flush" of the system. If your engine is hot when doing the back flush, start with a gentle stream of cold water at first so you don't shock cool the engine. City water at this time of year can be quite cold. I ran my engine at idle with a garden hose and used a "fertilizer mixer" in line to introduce the acid flush into the water stream. It just siphoned the solution in to the hose.

Make sure the cooling system has an outlet though... (the open top port of the radiator...don't be tempted to block it) City water pressure is slightly higher than your cooling system is designed for.

Since you're doing all that, may as well clean all the bugs and seeds out from between the fins of the core, too. Spritz the radiator core with a degreaser, let it sit, then apply gentle water from the engine side to push all the crud out the front. Even with an A/C condenser ahead of it, it is amazing how much stuff gets trapped between the fins. There were parts of my core that I could not see light through.

[Coastal220]

Would you guys also change the thermostat while at it? I know it's easy to get to when it fails, but they're pretty cheap.

[Palolo]

My vote: yes, why not?

============

I'm a belts and braces type.

Waterpump shows signs of failure and I change the thermostat, top & bottom hoses, and flush before I put the new pump in.

The way I look at it, the old pump has to come out, so the fan is off, and that gives me access and space to do the related bits at the same time.

[Shortsguy1]

Regarding the thermostat, be careful about snapping the bolts. I have read many here who started the thermostat swap as a "fast side project" with it turning into a major ordeal. Some folks recommend heat and others recommend using a penetrating lubricant. Just don't use both at the same time! I vaguely recall someone suggesting a quick strike on the wrench to break them loose, but don't hate me if I am wrong about that advice. I was in a similar situation to you on a similar car quite recently, and I chickened out regarding the thermostat. I just didn't want to open a can of worms if not necessary. Good luck.

[Coastal220]

Thanks Shortsguy1. Excellent advice.