Oh man, this cant be good... COOLANT LEAK M103 - PeachParts Mercedes-Benz Forum

Rahulio1989300E · #1 05-12-2006, 10:43 PM

Hello,

My name is Rahul, and I have been a member here on the forums for quite a while now...

I came back from college this summer to take classes at a local university... While I was gone I missed my car a lot, glad when I came home, get to drive all the time now!

When I left for college last summer, I noticed that my car was using a bit of coolant, the resivour needed to be topped off about once every 4 weeks. I suspected that the head gasket had maybe cracked, so I checked the oil and kept and eye on it by looking under the cap and inspecting the dipstick every night. I also kept an eye on the color of the coolant, to see if any oil was mixing with the coolant. But, the oil was never milky brown, and the coolant kept its color.

As I was gone, my father would use the car often, especially on weekends, when I would come home on certain weekends, I would always top it off.

I never let it get to the point where the cluster light would come on, I also made sure that there was at least 2 inches from the bottom in the resivour. Kept a 50/50 mix in the trunk just in case.

Then I noticed one weekend that there were water marks around the cap of the resivour, I immediately purchased a new cap and installed it. But the problem continued. Coolant was still leaving the system from somewhere...

THEN TODAY, EVERYTHING WENT NUTS!!!!!

I drive back to home, park in the driveway in front of the garage... since I have come home, I have always parked in the garage... anyways, I go into the garage to check if I have some cleaning suppiles. When I return, I notice a PUDDLE OF COOLANT ALL OVER THE CONCRETE! My heart drops!

I crouch to see under the car, to see if I can determine the leak, I am getting real nervous at this point.

I see two places that the fluid is dripping from, right from the center of the oil pan and off the cross bar behind it. This tells me a relative location of the leak, but still is very broad. The leak starts after switching off the car from a operation temperature state, the leak stops as the engine bay cools.

I suspect 3 things,
1) HEADGASKET FAILURE! Crap, this is like a $2000 job, my father would not agree to that price! My car is gone...

2) HOSE FAILURE! Easy fix, lot better than headgasket, I buy the part, take it to a garage, fix it myself. No sweat...

3) ENGINE BLOCK CRACK! Very unlikely but still possible, car is gone...

I am going to take it to a friends garage on Monday and put it up on a lift so that I can take a better look at it, it is dark here now, and not much space to work or even see, I am going to take my camera now and set it on a towel on a timer and let it take pictures of the underside of the engine in an attempt to see the problem.

My main question to you all is, are there any coolant hoses that run along the intake manifold side of the engine block?

The car is a 1989 300E, 193,300 miles M103 engine, I have put so much work into this car, I would get really depressed to see this car go away... I have refinished the zebrano wood pieces, rebuilt the front steering and suspension components, installed new speakers in the front, cleaned and polished the entire car, replaced a lot of rubber in the engine compartment, OVP, cleaned ICV, installed 94-95 turn lights, etc... Lots of money and hard work!

If it is a headgasket issue,
Are there people in the Arlington, Dallas, or Fort Worth area, who have experience with replacing the headgasket on an M103 that are willing to meet me for a weekend to replace the headgasket? It would be awesome to meet a group of enthusiasts who all want to learn about this operation, it could be kinda like a class for DIY M103 headgaskets. This way I could afford to keep the car I have worked hard on and keep it on the road. My father and I would be willing to take the people who help with the work to dinner and even pay a small stipend if you require it.

Please help, I am afraid it is the headgasket since it was replaced at 70,000 but not since then, thank you.

Really depressed,
-Rahul

duxthe1 · #2 05-12-2006, 10:52 PM

2 words....water pump.

Not an easy fix but nowhere as bad as the head gasket.

wbain5280 · #3 05-13-2006, 12:58 AM

I think that new car did it. Check for a bad water pump by looking for coolant dripping on the drivers side of the oil pan.

If so, there are instructions on this web site for changing it. I did it on mine a few years ago in January in 35 degree weather.

Hit Man X · #4 05-13-2006, 01:17 AM

I live in the DFW area... in Arlington.

rickpark · #5 05-13-2006, 03:53 AM

and make sure it hasn't cracked.

If this is the original radiator with the plastic headers, you may have a developing or completely cracked neck on the top of the radiator that is being held together by the hose clamp but leaks under pressure of running and with temperature. Loosen the clamp and attempt to pull off the hose. If the neck comes off, you'll know (and it won't come off if the neck is sound.).

This happened to me - I found out by pulling on the upper hose and the radiator neck came off. The plastic rots over time and fatigues with movement. Many others have posted similar experiences. What is perverse is what you are experiencing - no obvious sign when the car is turned off, and the coolant often evaporates from the engine heat while you're driving.

You are lucky if you find this is the case and can replace the radiator which is not too expensive and relatively easy to do. As an interim fix, there is usually enough of a stub left to clamp the hose on to until you can get home. It doesn't sound like coolant is leaking through the gasket, and the M103 block is pretty robust so if the engine hasn't been abused, it should be fine.

You are trying to diagnose the leak by looking where it runs-off to the ground when the source is likely higher up.

Attached is picture of my old radiator (original from 1990 300SE)

Rahulio1989300E · #6 05-13-2006, 11:02 AM

Thank you all for your suggestions, I will try inspecting the water pump and radiator neck. I will post back after I have done this! Thank you so far!

HitmanX, gimme an intersection!

Hit Man X · #7 05-13-2006, 01:06 PM

Division/Bowen area.

hihosilver · #8 05-14-2006, 01:18 AM

there is also a heater hose on the intake side in the rear of the engine, also the top of the radiator has a smalll hose and fitting with a oring, also the hose between the head and thermostat housing

AF300E · #9 05-15-2006, 04:50 AM

And the heater hose that goes into the head at back of the intake. (but the coolant generally runs off the bottom of the bell housing in that case)

AF300E · #10 05-15-2006, 04:51 AM

And the heater hose that goes into the head at back of the intake. (but the coolant generally runs off the bottom of the bell housing in that case)

Rahulio1989300E · #11 07-18-2006, 05:57 PM

Hello again everyone,

I have been busy with school and work.

Anyways, I replaced the waterpump, upper and lower radiator hoses, valve cover gasket and all that stuff related. Refilled with Zerex G-05 50/50 mix.

However, I still have the leak, I am not upset about the work I already did, its expensive insurance, plus, the impeller in the water pump did not look healthy at all and the shaft did move a bit when I applied pressure on it.

The leak is very weird, I drive my car every day, some days it leaks, some days it does not leak, I just dont get it, it does not matter what temp my coolant gets to.

It does not appear to leak when I am driving, only when I turn off the car.

Though it never leaks if the I just move the car around the driveway. (Engine never reaches operating temp) (Maybe hits 60C)

I isolated the leak to the back of the block, I found some white speckled water spots on the oil filter and rear heatshield. (Something is spraying!)

Tonight when I get back from school, I will take my trusty Canon SD300 and sneak it under the intake manifold to attempt find the leak.

DOES ANYONE HAVE A DIAGRAM OF HEATER HOSES NEAR THE INTAKE MANIFOLD OF AN M103???

Rahulio1989300E · #12 07-18-2006, 05:58 PM

BTW, I checked the heater hose at the very back and top of the cylinder head, its fine, no leak.

softconsult · #13 07-18-2006, 06:55 PM

My '92 M103 has had a headgasket leak for 130,000 miles. It used to be a combination of coolant and oil. Then I switched back to dino oil from Mobil 1 and the oil portion mostly stopped. I can crawl under the car with it idling and see the leak. It is very minute, but kind of spits from on point about
2/3 rds of the way back from the front of the block on the passenger side.
Requires topping off the coolant about every 400-500 miles. I have no oil in the coolant reservior.

Crawl under there with the engine running. Shine a strong flash light around the engine. Maybe get a telescoping mirror. I can't believe that you won't find it. Look at the bell housing of the transmission. Do you have any oil dripping on it.

Steve

PK ENGINEERING · #14 07-18-2006, 06:59 PM

Check coolant seal ring, lifting eye, rear left-side cyl head.

Remove oil filter for access.

seal ring part #: 012 997 51 48

Good luck.
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post script: I appreciate the fact that you are keeping the '89 Benz on the road. She has lots of miles left in her.

mad1 · #15 07-19-2006, 01:10 PM

Have you tried pressure testing your cooling system for leaks?