Hey fulcrum, you still with us on this? Any news?

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Ran the car last night and this morning the hose was soft.

It was hot today (100 F out) This morning I drove to work on the backroads and then the highway (Very little stop and go) The light came up towards the end of my trip. When I got to the parking lot I opened the hood, released the cap and watched as the coolant level rose when I did so.

On the way home the light stayed off on the highway, but then came on as I hit stop and go traffic. Temp went up a little bit but again one of my fans isn't working and even with the light on it didn't overheat.


My friend is next door right now, i'm going to sneak the lower pressure cap on right now and see what tomorrow brings.

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

Do you have 50/50 mix? Check it if you are not sure. If you have more water than antifreeze, you will have a lower boiling point. Are you slowly loosing coolant? You have to find where it is leaking! As for the ligh and overheat, you have to lose all the coolant in the expansion tank + more to overheat. Add more antifreeze to bring up the level to max and that should take care of the intermittent light till you lose more coolant.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

What you describe here is completely normal.

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Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Not 100% sure what the mixture rate is but it shouldn't be too far from 50/50

I do believe that I am no longer loosing coolant (Before it was leaking from the edges of the radiator) However now the area around the pressure cap has been developing residue.

Car doesn't overheat, only gets somewhat hotter in stop and go traffic (One fan is not functioning and the other only wants to engage when the AC is switched on)


Put the new cap on (120 KPA) and went for a drive while the car was still hot and with 94 degree ambient temp. Light flicked on and stayed on for a while....went to a Panera bread with two friends and the car sat around for a good two hours. (9:15 when we left and much cooler out)
On the drive home the light did not come on at all and the hose was a bit stiff but overall not too hard. Will update in the morning.

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

You very likely may need a new coolant reservoir! Over time the metal filler neck will separate from the plastic of the tank body to which it was from the factory originally fused. You may very well be able to grasp the metal filler neck and detect movement, if not when the coolant system is under pressure from driving somewhere spray some soapy water around the seam where the metal neck meets the reservoir’s plastic body. If the system is pressurized and there is air in the upper portions of the reservoir you should see bubbles.

This leaking can result in a failure to maintain pressure and lead to a lowering of the coolants boiling point resulting in the engine running hotter. When driving around coolant getting up to that area will get pushed out under pressure showing up as wetness or residue. This leak can also prevent coolant from the overflow tank behind the fender from being drawn via vacuum back into the reservoir as designed.

All that being said with regard to your coolant system you should rent the cooling system pressure tester from Auto Zone, pressurize your system and see how long it will maintain pressure; a rapid depressurization means a leak somewhere. Holding pressure is a good indication that the system is tight.

With regard to elusive SDL coolant leaks, here’s a thread from 8 ½ years ago of one I had and found just by luck:

http://www.peachparts.com//shopforum/showthread.php?t=33244

As far as the pressure in your system when the car is in operation from reading your posts so far you really have no empirical data on coolant system pressures and whether they are too low too high or just right. For $20 you can get a T hose bib, a length of hose and a gauge, and then install it into the line with runs from the top of the radiator to the coolant reservoir, that way you can run the hose with the gauge into the passenger compartment and observe the actual pressures and any fluctuations as you are driving. It would be some peace of mind at very little expense!

With regard to the coolant level indicator, the float has been compromised by leaking and as a result has lost some of its’ buoyancy that makes switch ultra sensitive because the float will move easier than designed under acceleration or when turning sharply. Replacement is the cure don’t forget a new O ring if you want to prevent it leaking.

It only fits one way with the float pivoting downward!

Just went outside to test the upper radiator hose. It's hard again (Not rock hard but there is definitely pressure on the system) Some nights it does this and others it doesn't? (will confirm this over the next few days)

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

What's wrong with the fans? They are critical when stuck in traffic to bring the temps down. Aluminum heads do not tolerate overheating well.

You really have to do some of the tests that's been suggested.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Only one of them is engaging and even that one will only to turn on when the AC is engaged. (They used to come on all the time....I've been told a new sensor will fix that) I tried to remove the fans to fix them but they seem to be stuck in place
http://www.peachparts.com/shopforum/showthread.php?t=281657

dieseldan44 is going to be kind and bring his tester by sometime in the next few weeks.

I get the feeling though that this entire debacle is partially reliant on the ambient temperature. The past two nights while driving the light hasn't engaged once yet during the day it would kick on without hesitation.

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

dieseldan44 was good enough to come by tonight and brought his tester with him. We did the test and he was also kind enough to give my brother some information on veggie cars.



There is gas in the coolant system Already called my indy; car is going in tomorrow to have the head pulled (HOPEFULLY its just a head gasket. I think i'll be alright since i've had no issues with overheating)

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

Very unfortunate. These later aluminium heads were less prone to failure. There is a slight chance of a head gasket hopefully. But a serious search for the crack will have to be made if not immediatly obvious.

The crack in your case may be very very small. Symptomatically it is a crack remember. I would pre locate a replacement head at least before tearing the engine apart. That way if one is required you will both have a source for it and semi control your costs.

Proper weld repair of a newer series head by the right shop might be considered.If you were doing the job yourself at home. With paid for labour I doubt I would risk it. Also you have to get access to a really good shop for that particular weld repair anyways.

Most areas do not have a truly competent place locally. On the older series heads preceeding yours. That approach would not be a good ideal even with no outsourced labour. In todays world any of these cars can develop into a serious money pit if all labour is sourced out.

fulcrum,

pleasure stopping by today and meeting up with you. wished i could have hung around longer but we had to get back to boston.

i also wish i could have given you better news than that the head has to come off

i have no personal experience with them, but I'd stop at nothing less than getting a Metric Motors head for the car. I haven't heard of any machine shops, at least in the Boston area, that reputable indy's send their MB diesel work to. but then again I have no experience with a 603 and their aluminum heads so I'll retreat to the sidelines

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I know I'm going to get flamed for this, but have you considered this? I've seen this stuff work on Cadillac Northstars, and have revived one myself using this.

http://www.rxauto.com/faq.htm

Since yours is so minor I imagine it would be successful. This is not the cheap parts store stuff that you just pour in, leave, and allow it to clog up your cooling system and heater core. No real harm is done if it doesn't work.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

I've had a couple of engine heads repaired by competent machine shops which were able to weld up cracks in aluminum heads, but it's definitely not something I would attempt at home.

Done properly, it requires preheating the head, welding the cracks while the head is still hot, and then being cooled at a controlled rate, before machining the weld and possibly correcting for warping of the head during the welding.

My vehicles that it was done on were Isuzu engines that were prone to warping the head, and then causing head-gasket leakage, as well as valve seat cracks.
How this compares to where or how the MB head developed a leak, only the tear down will show.


Best of luck, and hopefully it'll prove to be a gasket alone, not requiring any major work to remedy beyond that!



On the topic of the stuff Tyler mentioned, does anyone know anything about it? It looks a lot like WaterGlass, currently notorious for being put in the lubrication systems of the Cash4Clunkers programs victims.
That chemical was previously used for cooling system patching, but I don't know what brand names it's marketed under...

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...

I dropped the car off at my indy this morning and there is a machine shop right next door to his shop that he uses (My indy actually owns the entire building so I guess they have a pretty good working agreement)


I haven't heard from him yet as to what will actually be needed (Just head gasket or entire head....) I'll post as soon as I find out.

__________________
1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."