Just an FYI,
I had to replace the water pump on my 92 300E last week. All of the coolent that came out of the pump ended up near the back of the engine on the ground. From what you have stated I would think that the water pump would be the worst case sitution.

boy I wish I would have found this board before today. It appears I have been putting off getting my car fixed for nothing! Once I get it fixed I am going back to that Mercedes Dealer. I have the write up they gave me and it says head gasket, water pump, radiatior. By the way, I think it does say hoses. If I really don't need a head gasket they are going to hear it. This was 3 years ago that they gave me the diagnosis, and I have the exact same symptoms today as I did then. They have not gotten any worse. The only thing that has gotten worse is the amount of coolant that is leaking. I agree with what you said in an earlier post, if I really needed a head gasket I think the overall problems would be worse today.

Get it fixed before you roast the engine at a stop light.

Could be hoses, radiator, water pump or all three. Likely not headgasket.

sounds to me from your description that you will need the following----------fan clutch-----probably radiator-------radiator cap----and depending on the colour of the plastic a new radiator reservoir.it's possible that the water pump is leaking[especially if the leaking happens as the engine is allowed to cool]----the almost instant heating up when you come to a stop suggests that the fan clutch is at fault.when warmed up you can probably turn off the engine but the fan will still be turning for a while?the radiators are made from aluminum and over the years the tubes will shrink so that at idle there is not enough flow-----but as soon as you hit the gas and speed up the temp comes back down.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

david you pretty much have nailed it. Though I would not say the heating up is actually "instant". I would say that it happens at every red light if I am stopped there for more than 15-20 seconds, though I have never timed it. I do notice that the longer I drive the car the quicker it is to heat up at a light.

You are right about the fan still going after I shut off the engine. It does that occasionally, probably because I don't drive it that far anymore. I can say that one time I drove it without coolant was the first time I noticed the fan still going after I shut off the car. I was pretty worried when that happened.

I called Mr. MB Motors in Tarzana today and that is where I'm going to be towing the car to soon. Thanks for your input. Once I have a diagnosis I will come back and post it.

You never said at what temperature the temp guage is getting to.
How high does it gets?
On normal driving , you should see 80+
Stuck in traffic during the summer time, 100deg is not abnormal

I thought I did on the other page. It goes from about 80 to close to the 100 degree mark or just a little over. But then as soon as the traffic light goes green and I accelerate it goes right back down to 80. It probably does that in about 5 seconds or so.

I notice that the longer I drive the car, the quicker it is to heat up at a light. But the temp gauge always goes back down. I tested it a few weeks ago by letting it sit in park for awhile. After it got close to 100 I put the car in drive and drove down the block and the temp gauge went right back down to around 80

The only difference I have seen in the car since the 2 plus years the stupid dealer said I needed a head gasket is that it is loosing more coolant.

Water pump and fan clutch will fix you up.

The viscous fan clutch should engage the engine fan and cool the engine at idle -- it will go up to about 100C otherwise, where the electric fan comes on.

The water pump leak shows up about half way back, because the coolant runs down the engine along the head/block interface and drips off the rear corner of the oil pan sump, it drips onto the block.

The water pump will be expensive, it's a fiddly repair. However, a new pump and fan clutch should fix you right up.

Have them change the coolant to Zerex G-05 or MB coolant at the same time, do not use green antifreeze in that engine, it causes corrosion and will plug the radiator.

Don't be shocked if you also need a radiator eventually, too.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Finding a water leak is not very easy.
The best way is to pressurize the cooling system when the engine is cold. Any good shop must be able to do this.
The engine has to be really cold, best to let it cool down overnight and test in the morning.
Overheating at a stop sounds like a bad fan clutch, my 300SE behaved the same until I replaced the clutch. Also if you radiator has never been replaced it won’t be very effective any more after 16 years.

Rob

I've been using the green antifreeze, I guess I should stop using that?

I replaced my water pump in my Miata about 5 years ago and I know it cost some bucks. That thing failed at my office in the parking garage. I'm glad it did it there instead of on the freeway somewhere.

Thanks again everyone for all of your responses. I am glad I found this board, I have learned a great deal. I will post once I find out what is really wrong with my car, I am taking it to Mr. MB Motors. If I do not need a head gasket, and it does not sound like I do, the dealer that told me I did is going to be sorry they told me that. Even more sorry that they gave me something in writing saying that I needed that, a valve job, hoses, radiator and water pump. They even put in writing that I needed new spark plugs. I found that a bit interesting considering I got all new plugs 6 months before when I had a tune up at another shop.

Awww, really now. You know you'd be better off with all these things replaced. After all, the parts to be replaced are no longer brand new, right? So obviously, brand-new would be better. The dealer is probably just doing an extra-special job of keeping you safe.

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2012 E350
2006 Callaway SC560

It is for me hard to say why the dealer made those recommendations, you did not give all the details; mileage, maintenance etc.

A temperature of 100 degrees is not serious overheating, if the cooling system is not leaking this should not be a problem. It indicates that some parts of the system are not as good as new. For a daily driver that has to endure summer heat in traffic jams I would fix it as soon as possible, but since you only use it once a week this may be different for you.

The water leak has to be fixed! If the water level drops below the head gasket it will overheat and blow out. Also the head my overheat an warp. These are much more expensive repairs than fixing a leak!! Have your cooling system pressurized (when really cold) and have the leak fixed. With the engine warm the water vaporizes making it hart to find the leak. With the engine running the fan will blow the water toward the back, making a failing water pump (front of the engine) look like it is coming from the rear..

If your car has 400K mls without a valve job the guides and seats may by worn, with 40K mls it would be very unlikely.

It is always best to make very clear to a Dealer/shop what you want to be repaired. If they recommend other repairs they must be able to explain why. It is up to you to follow their recommendations or not. You may be disappointed with the dealer if your car would have a problem shortly after being repaired and they did not warn you about it. With expensive repairs a second (or more) opinion is always a good idea.

Rob

I had the same problem you had years ago on my 300, everyone thought it was the head gasket including me, I was leaking coolant bad once it heated up, well It wasnt the headgasket althouht I did need one for the leaking oil, the coolant leak from the back turned out to be a hose that was located in the back of the engine a simple repair.

Thanks for the info Leon!

Rob - my car has about 88,500 miles on it. I bought it used about 4 years ago. I could tell that whoever owned it before me did not drive it much, the interior looked like it hardly had been sat in. I bought it from a place that sells very high end used cars, this one was pretty much the bottom of the barrell in their lot. But it has that old boxy shape that I like so I got it.

I got a tune up after I bought it, replaced the distributor cap, flushed the coolant and flushed the auto transmission, got an oil change. Considering gas prices over the last few years, I have not driven it much and mostly drive my other car. I bought it at around 82,000 miles. Did a car fax check on it. I had my regular mechanic look at it before I got it. I'm driving it once a week so it has a chance to get out and 'exercise'.

I did have to replace the shocks about 2 years ago, found out they were the originals, so I think it is safe to say that maybe everything in there is original. The car only had one owner prior to me and it was an older couple who said that was their 'sunday driving' car. Which probably explains why the low mileage for a car in Los Angeles.

I've got a 93 Miata that I bought new, I always get it serviced on time and right now there is nothing wrong with it.

Just curious. What was the reason for replacing the shocks?

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2012 E350
2006 Callaway SC560