Car in question is a late-model '79 240D auto.

Hard to start when cold, smokes a lot, and coolant disappears out of nowhere. I'm putting my money on a head gasket failure. Wasn't really expecting this, so what should I do? the thought of pulling the head off scares me, and I don't have the proper tools/equipment to pull this job off. Worst of all, it's her daily driver; she needs it.
I have a HF compression tester that I was planning on using on it, because it's so hard (if not impossible) to start the thing up during these cold mornings. However, going through the trouble may just seem like a moot point now considering all other factors.

Try and fix it? Or sell as a parts car?

__________________
- 1979 W123 240D 4-speed, 390k miles

Hows your fuel delivery ?
How long since you set the valves ?
Whats the condition of your battery ?

240's are pretty easy to work on.

For a $100 or so you can get all the tools you need for DIY fixing
Harbor Freight Tools

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

You may be jumping the gun with this car. Based on the symptoms that you describe, a bad head gasket is not the likely problem. There are a few reasons that the car may be hard to start on a cold morning, and they can appear to indicate a serious problem when acting in combination. Smoke that is smoke, not steam, is not much of an indicator of a blown head gasket. It is amazing how much coolant can disappear if there is a very tiny leak in the radiator that goes unnoticed, more so if you have a faulty radiator cap.

Have the valves been adjusted recently? Had they been adjusted regularly prior to the last adjustment? Are the glow plugs known to be good? Have you tried cycling them a few times before trying to start?

Since you already have a compression tester, it would be a good idea to test. If you have low compression across the board, or a pair of low cylinders that might indicate a bad HG, then you will have more quality information knowing your compression numbers. You should, of course, check and adjust valve lash before you do a compression test. Testing through the glow plug holes will also force you to examine the glow plugs. You might have a bad one, and if you still have the original loop style plugs that would mean that none of your glow plugs are working. For that matter, the problem could be as simple as a bad glow plug fuse.

A pressure test of the cooling system may throw some light on the situation as well. If the system can't hold pressure and you can't find a leak, then you may very well have some seepage at the HG. The point that I'm making is that a decision to pull the head should be made only with a lot stronger evidence than is being presented. OTOH, a decision to get rid of the car may be the easiest way out if other circumstances dictate.

__________________
'79 240D

left coast is simply saying ...dont assume the worst. None of were born with wrenches in our hands, we all learned one bolt/nut at a time

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Couple of things:

1) Adjust the valves, test the glow plugs, take a compression test.

2) Don't be afraid of the head gasket. I pulled an engine this summer after having done nothing greater than change transmission fluid in the Corolla the year before. Most of the work is just "intelligent grunt work" -- follow directions, get the right tools, and you will be fine. You can do it.

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

the chance of a catastrophic head gasket failure on a 616 is extreeemely low.

a friends 240d was getting impossible to start and a new set of glow plugs fixed that problem. i think yr gf's 79 still has the series plugs which makes it even more imperative to check the glow plugs first!!!

__________________
1981 NA 300D 310k miles

There are many possible causes for loss of coolant:
Visible radiator hoses - do an inspection. Look for signs of rust deposition from dried radiator water.
There is a tiny section of radiator hose between the front engine thermostat housing and the water pump I think. It's a regular inch or so length of hose that is hard to see unless you know where to look.
Pinholes in the radiator - look for the signs of water leaking out under pressure.

As for hard starting - glow plugs, glow plug timer, wires. Lack of air flow - check filter for blockage.

Fuel delivery as stated.

Also as suggested, don't jump to conclusions that all is lost. Check the little stuff first and rule it out.

__________________
Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

Thanks for all the replies, guys. I'll get on some stuff tomorrow.

I recently did a valve adjustment on her car; I tend to do them twice a year to both of our cars, if nothing else; once before winter/cold autumn, and one after winter/before the warmer weather. They hadn't changed much from the previous adjustment in May; maybe two had tightened enough that I actually had to do something.

I've been iffy on the battery; it always tests out good in battery checks at auto stores and even my own tests; I use a multimeter and a load tester from Harbor Freight (Alternator/Battery Tester) The part I'm iffy on is that besides the fact that it says Interstate on the back, there's no markings whatsoever on it. Money pending, I've been contemplating getting a new one. I've heard good things about Interstate batteries; got one in my own car and it's awesome.

I did replace the starter motor about 4, 5 months ago with a unit for turbo engines (spins faster I guess) to help alleviate this issue.

I'm not sure how I would check fuel delivery...I keep tabs on the fuel filters, though. Just replaced the pre-filter about a month ago and the spin-on about 2, 3 months ago. Haven't had a chance to inspect the tank screen, however. I caved a while ago and bought the 'special socket' from y'allknowwhoSource to replace mine on my car, so I have the resources/know-how.

Same deal with a radiator pressure test, checking the glow plug box/timer...elaborate how-to please?

The engine on this takes the later-style pencil glowplugs. Like I said, it's a late-model 79, almost 80. Mine is an early model, stamped 1978; it has the older, larger holes that I upgraded to a parallel system. However, I have little history on her car so for all I know the engine was swapped from another car.
Now, I've seem some posts on here detailing glow plug testing on these pencil plugs using a multimeter to measure resistance and whatnot...I got lost. I should just take them out and test to see if they even get red-hot first?

__________________
- 1979 W123 240D 4-speed, 390k miles

This is the best way IMO to test them. Use a set of jumper cables and a good battery to test them, the tips on all of them should get bright red.

If your worried about a head gasket leak, however unlikely it is, buy a cheap diesel compatible leak tester. They fit in where the rad cap goes and test for combustion gasses in the cooling system.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

Don't waste time...

Take the car to a repair shop for a cooling system pressure test.

If there is no external leak = 99.9% odds the head gasket is bad.

If you continue driving with a bad head gasket = begging for more damage or catastrophic failure.

*************

After 34 years, the head gasket is IMO an expected maintenance item.

The DIY requires few special tools.
Untitled Document


If you share your (CITY) location, a local member may be able to help you.

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Home Made Special Tools, This is where members can share how they made special tools
Home Made Special Tools, This is where members can share how they made special tools


Cavitation
Cavitation

1980 240D CRACKED cylinder head + cavitation damage
1980 240D CRACKED cylinder head + cavitation damage

1985 300TD head gasket repair
1985 300TD head gasket repair

240D (616) # of cylinder head bolts? (how many of each length)
240D (616) # of cylinder head bolts?

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<


If this is a critical vehicle that can't be down for service, I suggest you:

#1. Call me = check your PM for my number. Note: You also have E-mail.

#2. Buy a good used cylinder head
Mercede Benz W123 240D 616 Engine Head 4 Cylinder Diesel Non Turbo 616 016 14 01 | eBay

#3. Take car and spare cylinder head to a repair shop.

#4. Pick up and pay for the completed vehicle in a few days.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

For some reason that special tools link isn't working.

My location is Marysville/Everett, WA. Anyone know of a reputable shop around this area that can/will do an old Benz? Also...roughly how much is a head gasket replacement job from a shop?

I did fail to mention that I am getting some leaking from underneath the IP... it looks like oil but to the touch it's way too thin to be oil. A coolant/oil mix, perhaps?

Also, check your email...

__________________
- 1979 W123 240D 4-speed, 390k miles

Try this..... http://www.peachparts.com/shopforum/washington/183891-everett-sno-co-gp-automotive.html I'm in SW Washington, about 3 hours away. If I had time off work I would give you a hand checking it, but it sounds like you have a good handle on it!

__________________
2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Here are direct links to the service - repair manuals:
FYI If you have problems accessing these documents, try using Internet Explorer..

The DIY requires few special tools.
Untitled Document

Here are direct links to the service - repair manuals:
FYI If you have problems accessing these documents, try using Internet Explorer..



Mercedes Benz (EPC) Electronic Parts Catalog
EPC-net Online

Remove all versions of JAVA on your computer using add or remove programs or programs and features in the control panel.

Go to Where can I get the latest version of Java 6?

Download the 32 BIT version of JAVA, version 38, install and retry EPC.net.

32 BIT is required for EPC.net and version 6.

Version 7 or 64bit versions are not supported at this time.

***************************************************

For those of you who are unaware, Mercedes has posted up all the service manuals for our favorite cars on their Star TekInfo website, no need to login at all.

STAR TekInfo

Click, MB Workshop Resources -> Service Manual Library CD/DVD

Here are direct links to the service - repair manuals:
FYI If you have problems accessing these documents, try using Internet Explorer..

124:
Model 124

107:
Model 107

123:
Model 123

126:
Model 126

201:
Model 201

Hope this helps!

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

I can confirm that startek does not like Firefcx, even the latest version.
Seems like IE is their 'preferred' browser for full operation.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Stab in the dark but I would say $1000-1200 for the HG.

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."