Hi guys,
I've been having trouble with my 2003 300M recently. Not sure if all these are related, but here's what's happened.

1. Climate Control panel quit displaying the screen, so I got replacement from junkyard. It didn't work either. In fact, it also seemed like I couldn't control the heat very well anymore. I'd hit the up/down arrows to change the temp of the air, but it didn't seem to do anything consistently...just intermittently would work.
2. A few days later, the car overheated. At first, the temperature would go up and down from 1/2 to the red zone. After about 5 minutes, it stayed in the red for a full minute so I pulled over within 1 mile and shut off the car.
3. When it cooled down, we put water in it and took it home. Husband replaced the thermostat.
4. After new thermostat, we discovered water pump leak.
5. Took the car to the shop to replace water pump (and timing belt while in there since the car has 153,000 miles). Still getting hot on the way, had to pull over and cool down every 5-10 minutes.
6. Shop did the work, I picked up the car, it was still getting hot right away (within 5-10 miles).
7. I took the car back to the shop. They did a block test and they said my car failed the test. They said they had done a test the day before but my car had passed then. So now they are saying it is a blown head gasket, maybe more...

So my questions are...
1. Can a block test be negative one day and positive the next?
2. Anything else it could be?
3. Is my car worth fixing? (no other issues, but it has 153,000 miles so I don't know if my car will keep having issues after this or not) I still owe about $4,000 on it. From most of the things I've read about 300M's overheating and replacing head gaskets, people seem to keep having trouble after that.

Any help is appreciated...thanks!

 

More then likely the heads are warped from an over heating issue as for as the valule of U doing the work that's complacently up to u do U like the cars blah blah also can u afford a new one and all its issues or a monthly payment that's all on your end .

 

I was having over heating issues. Changed a bunch of crap and I was told it was this or that and it ended up not fixing the issue. My boyfriend decided to fix it himself. We started by using only the best antifreeze (no half & half) get the full stuff and do it 60 antifreeze 40 water and make sure uget all the air out thru the bleeder valve. The mechanic said to bleed it drive bleed it drive it and so on till u get all the air out but thats insane, to much work. He just got all the air out by holding the bleeder valve open as he poured the antifreeze in , so it pushed all the air out up thru the valve till antifreeze comes out. We ended up replacing the radiator, thermostat, thermostat gasket hoses, coolant reservoir tank and few other thongs that never fixed the issue till we did this. Hasnt overheated since. Hope I helped some. I have a 99 300m

 

So you bled the system and that was your fix? or fixing the heads was your fix?

 

Yes bleeding the air out and putting the 60/40 coolant/water fixed our issue

 

Didn't have to fix header

 

mmm not likely for 2 reasons 1 there is no air in the system unless you have a leak or created a leak.

2 simply bleeding the air out is not a fix it should have been done after any coolant related repair.