Overheating problem solved - PeachParts Mercedes-Benz Forum

Capt Kirk · #1 01-21-2002, 08:40 PM

Well, I just got back from the Road Test, looks like I fixed my over heating problem.

http://www.peachparts.com/shopforum/showthread.php?threadid=28308 (covered there)

Seems like the problem all along was a bad Thermostat, all 4 of them.
Here's the story that lead up to this discovery:

Yesterday I replaced the Waterpump with out a problem and filled up the system with 1.5 Gallons of MB Antifreeze. That helped a little, about 3C

. So it was back to the drawing board considering I had replaced every major component in the coolant system and also flushed it god knows how many times (once with MB citric acid powder). The only component that I couldn't say for sure was working right was the Thermostat. Also the way the car was acting pointed to the thermostat as well. I decided that Monday I would get another T-stat to try out.

Now comes Monday, I first went to my local MB dealer (where they know my name - that maybe a sign) to return the old waterpump core. But since I had already returned the first T-stat there I didn't feel right buying another one. As a result I drove down the Park Place since I also had to return a set of Subframe mounts I bought extra (a subframe mount kit comes with both sides). While there I bought another T-stat, Antifreeze and 2 bottles of Citric Acid. When I got home I tested the T-stat - it opened at 200F (91C - concurrent with my problem). I drove back to return it, this time I brought my testing equipment with me to try out thier T-stats since it takes an hour to drive out there and back.

Cutting to the point - the 4th MB Thermostat was also bad, I went to Autozone I purchased a Whaler T-stat from them witch works. I also called MBNA to tell them of their bad batch of T-stats.

I'm also thinking of writting a letter to them telling them of my whole problem that stemmed from a batch of bad T-stats.

Capt Kirk · #2 01-21-2002, 09:16 PM

Yes I put the Thermostats in correctly. I also Boiled them in water, thats how I know when they were opening.

And it was 4 bad Thermostat's from MB. The 5th one is from Autozone made by Whaler.

be459 · #3 01-22-2002, 06:27 AM

Kirk,

When you boiled the bad t-stats in water, what was the tempurature they started open? Was the tempurature off a lot?

David

Capt Kirk · #4 01-22-2002, 08:35 AM

They started opening around 190-200.

The one from Autozone started opening around 170-180.

be459 · #5 01-22-2002, 02:32 PM

I don't mind 190 degree but 200 sounds too high for a t-stat rated 180.

Thank you for the reply.

David

Capt Kirk · #6 01-22-2002, 04:49 PM

well you could see it was more open(by just a hair) then at lower temperatures, but it didn't "spring" open until 200.

Ken300D · #7 01-22-2002, 05:46 PM

Man.

I wonder if that run of bad thermostats is selling any radiators for the dealers?

"I'm sorry sir, we can't take a radiator back once its had antifreeze in it and been hot."

I got one new off the shelf once that was "sticky". It wouldn't open up until near redline - then it was fine and would sorta regulate temperature. Sometimes ya just gotta try the part again. Especially if it runs cold with no thermostat.

Ken300D

Capt Kirk · #8 01-22-2002, 05:59 PM

I figured that putting it in warter on the stove all the way up to boiling would unstickyfy it.

I also boiled them 2-3 times each (except for the 2nd one, I boiled that after I put the Autozone one in, I figured that MB T-stats would work)

Ken300D · #9 01-22-2002, 06:41 PM

Oh. Let me clarify. It would stick closed every single time when it cooled off. To use the vehicle you'd have to run it briefly up to near redline to unstick the thermostat - THEN for the rest of the time the engine was warm it was fine.

Let the whole engine cool off, and it was RED LINE again!

I lived with that for at least a year - a backup/snow 4WD vehicle.

Such a pleasure to not sweat the red line anymore.

However - you are set now - a cool machine...

Ken300D

william rogers · #10 01-22-2002, 10:15 PM

It's real common to get one after another bad thermostats for American cars but of course it real common to get one after another bad American cars......
William Rogers....

#11 01-23-2002, 12:28 AM

I've found it to be not just small items like a thermostats. Last month while trying to get my cruise control fixed we, the service manager,mechanic, partsman, and I, went through 3, thats right, 3 new out of the box amplifiers before finally robbing one from a car on the lot that we knew worked. There were some annoyed people that day.

Bill.

240 Ed · #12 01-24-2002, 05:58 AM

Well, that's just great.

We can't even trust OEM thermostats

I have always told people never bother with an aftermarket t-stat, get an original. I had this problem with a 280ZX turbo and solved the same problem with an OEM part

....so I dunno...

Capt Kirk · #13 01-24-2002, 08:38 AM

it was probably a bad batch. The lesson Learned here is to always boil the T-stats to make sure they work.

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