New to the site.. Just bought a 91 300CE, been driving it for the last 2 months and today when I was driving to work I notices some smoke coming from my hood... I then noticed my temp gage was really hot and my coolant level light was on.. I quickly drove up to my office and parked the car. I then opened the hood to find that the neck on my radiator had snapped off and my hose was disconnected.... I was able to reconnect it because it still had a bit of a lip left on the broken off part to reconnect the hose to and radiator, I refilled my coolant levels and then drove the car... It seems to be working fine, but I did find some oil in my coolant. My question is where can I find a "Do it your self walk through". I have found a place where I have ordered a new radiator.. but I am unsure if there are any special things I should be aware of before I start this project. I will be removing the damaged radiator and installing the replacement unit. I am aware that transmission fluid lines do run to the radiator, but I am unsure if this is a tricky installation or is it a simple replacement. Any help and advise is greatly appreciated. Thank you all .

Hi MARINE_V,

Here's my 2 cents worth...If you found oil in your coolant, then you most likely have a bad head gasket. When my head gasket went, it blew out the bypass hose from the water pump to the thermostat housing, and there was oil in the coolant. So that is my theory as to why the connector/hose snapped off.
Before you replace the radiator and any associated hoses, you need to verify if the oil in the coolant is due to a bad head gasket.

I also had to replace my radiator a few years ago due to a weak/cracked neck, but it was unrelated to the head gasket problem.

Good luck,

Dave

__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible

thanks for the info..
I believe the oil is transmission oil not motor oil. Are the 2 metal lines going into the right side of the radiator motor oil lines, transmission lines, or power steering lines? It appears all of the other hoses are fine. It was just the neck that busted off of the radiator.. at any rate I am very much concerned that it could be a head gasket, but the car is running fine and it is not over heating.. I am really hoping this is not a big repair job... did you replace the radiator you self or did you have the deal or mechanic do it?
My dealer wants $500 for a new radiator.. and $250 to install it. I found a Nissens Radiator for $175.63 and Behr (Alternate Brand) for $198.69.
Regardless it needs to be replaced.. I just do not know if I should do it and save my self the money or should I just buy the unit and have the deal replace i?

Marine_V, definitely confirm the condition of the head gasket before even thinking of replacing the radiator. Depending on your DIY skills and available tools the radiator replacement is relatively simple. Recommend ordering a new Behr radiator (with metal-reinforced hose connections) online, replace the hoses if they appear original or are in bad shape. The two metal lines connected to the base of the radiator are transmission fluid lines. Be sure to use MB coolant.

__________________
Fred Hoelzle

MarineV, to expand on some of your questions:
The two lines are for the transmission cooler. There is a little tank inside the radiator that transfers heat from the ATF to the coolant. Indeed, if that tank cracks, ATF will get into the coolant (and coolant will get into the tranny fluid!). Replacing the radiator is really straightforward; just unhook the two lines, very little ATF will run out. the radiator is just pushed down on the rubber grommets, and held in place with two clips on the top, very easy.
The upper hose area is notorious for breaking.
The Behr radiator is the original brand, but the replacement is nowhere as robust as the original. But that is all you can find these days, should be fine.

All that being said, yes you should confirm the condition of the head gasket.
Again, a very common failure on these engines, about 100k miles is typical for gasket failure. Also, check the tranny for water/foam in the fluid. If you think the stuff in the oil is ATF, then you had better be sure no water remains in the tranny fluid.

DG

thank you all for your helpful input... OK I have decided to replace the radiator my self.... how do I first check if the head gasket is bad ? DO I need to take it the dealer or mechanic to check it? from what I see there is no oil seeping any where around the motor. it looks pretty much clean. How much should I expect to have the head gasket replaced? Maybe I will have then do that first. Then I will replace the radiator after that..

BTW.. I am going to be taking pictures and posting them along with a walk through... Just so that if any one ever has this issue on this car they will be able to do it themselves and save the money. Any suggestions to this project will be helpful and greatly appreciated... once again thank you all.

Replacing the radiator and hoses is pretty easy, replacing the head gasket is much more involved, but it can be done providing you have the tools and time.
Last August I replaced the head gasket on my '93 190E 2.3, and yes, the 4 cylinder is easier to do, but still takes mechanical knowledge. It was obvious that my head gasket was bad due to oil in the coolant....when the bypass hose blew, coolant went all over the hood pad and engine compartment and the coolant was very oily. The head didn't show any signs of leaking, the head gasket failed internally and there was a break between one of the oil and coolant passages.

I removed the head and had it resurfaced at a machine shop along with a valve job and new valve guide seals, all new rubber hoses due to oil in the coolant contaminating the rubber, new engine mounts, along with anything else that looked worn or defective.

It's been a year now and no problems. If your car was mine, I would do it myself.

*NOTE*...If you decide to just replace your radiator, inspect the coolant real close when you remove the lower radiator hose. Mine was very oily so I had to flush my almost new radiator extremely well along with the engine block and reservoir tank before installing the new hoses and adding coolant/water.

Good luck,

Dave

__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible

Marine_V, my daughter just paid $2,000 for a head gasket replacement on her 1991 300CE. It's a time-consuming job and best to use a hoist to remove the head. Certainly a skilled DIYer can handle it, provided you know how to reinstall the timing chain tensioner and get the overhead cams aligned correctly. Do a "Search" on head gasket ... there is lots of information available. The Haynes Repair Manual gives a comprehensive description of the head gasket replacement.

__________________
Fred Hoelzle

Here is a list of the parts I have order for my project. I am hoping to get the new radiator installed by Wednesday.
Thanks guys for all of your input. With your help I feel confident I can do this my self.

Fischer & Plath
8mm Copper Seal Washer; 8x14x1mm
$0.30

Fischer & Plath
8mm Copper Seal Washer; 8x14x1mm; 8mm Copper Seal Washer; 8x12x1mm
$0.20

Elaplast/CRP-Contitech
Cooling/Coolant Hose; Bypass Hose from Water Pump to Cylinder Head/Pipe to Cylinder Head Flange
$8.25

Elaplast/CRP-Contitech
Cooling/Coolant Hose; Elbow Hose from Crankcase to Oil Filter Housing
$6.26

Behr
Radiator
$198.69

Metzeler/CRP-Contitech
Radiator Hose; Upper
$11.35

Meyle
Radiator Mount/Installation Kit
$6.91

CRP-Contitech
Serpentine Belt/Ribbed Drive Belt <<<---- (I figure while I have the room, I may aswell replace the belt while I am at it.)
$24.54




Ferdman-That is half the prince I paid for the car.. wow The timing chain and overhead cams alignment is what really scares me, but I will see if I can handle this project I can see if I can tackle the head gasket in the future.

Marine_V, I guess you realize that you need to remove the water pump to install the bypass hose between the water pump and the head. That's a challenging job itself ... wait until you replace the head gasket to replace the bypass hose. It would also be a good idea to buy a new O-ring for the water pump/head connection to avoid a potential leak.

__________________
Fred Hoelzle

To be honest no I did not know that..... but yes you are right I need to get that o-ring while in the dam thing.. there is no point in doing the job and not doing it right. At least the parts are not very expensive.

So, Marine V; when you replace the radiator you should have a good chance to determine if you have ATF in the coolant, rather than motor oil.
When you remove the old radiator, you can easily remove the end cap and take the ATF tank out. Then just examine it for leaks, and that should tell the tale on the ATF. But, also check the fluid in the tranny, just to be safe. Best way would be to pull the pan and look for water in the bottom, but if there is much water in there, it should show up as foam on the stick after driving, or you could pull the pan drain plug and drain out what you can (approx 2 quarts) and let it sit awhile. The water will separate out I think.
If neither of these checks indicate ATF mixing with coolant, then you most likely have a head gasket issue (very very common, while ATF tank leaks are much less common).

The guys are right about the head gasket R&R; time consuming and expensive for a mechanic to do; but pretty straight-forward and easily doable at home, if you take your time and reference all the info available here on the Forum. Jump in there; the guys here will keep you straight.

DG

S-Class Guru- Will do.... how long will a head gasket job take? Is it a weekend thing? or could I accomplish it in one day... keeping in mind I am a newbie to MB cars. I mean, I have replaced and installed the fuel injection system and wiring harness on a Mazda RX7.. not quite the same car, but I feel confident that if I take the time I can do the head gasket my self. As I stated before I am only concerned with the timing chain and overhead cams aliment. Maybe I should have read more about the the car before I bought it hehehehehe.. the problem is I really really like the car.. I just want to fix it up. Little by little I am going to get it running perfect. I have already replaced the front disks and pads.. I had the rears and pads ready to be install when this radiator thing happened.. I have a new set Carlson staggered Replicas ready to install too but that too will have to wait till I get this pressing matter resolved first.. It is one thing after another with this car. As I stated before I am very grateful for all of your input and information.

You should also rebuild the head. If you take it to a machine shop yourself, it should not be much money and the work would be the same.

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J.H.
'86 300E