Coolant loss and heater smell from C36

[amg kodiak]

Hello all,

I think i know the issue at hand, but I wanted to get some second opinions.

This weekend I drove out to Davis (20 miles east of Sacremento) for a friends graduation. It was pretty damn hot and I drove the whole stretch there at about 80 mph with the AC blasting. The car never really go too hot until I was in town and the it peaked out at about 115 deg C. On the way way home we go stuck in traffic and roasted for about 3 hrs with AC on full and averaging about 20 mph with sections letting us get to 60 mph before slowing to a halt again. On the home stretch (running at 80 mph again) the low coolant light came on. I drove home (the car was running at about 82-85 deg C the whole time with the light on. I added a 1/2 liter of water to the resevior at home after the system had cooled some.

The coolant is darker than normal, I cannot tell if there are drops of oil in it, but the color is more redish than orangish, which to me is a sign that oil is in there. I check the oil and the level is fine, the color is good, but I don' t know how to check if it has coolant in it. Also the heating / cooling system has smelt of coolant (sweet) for the past week or so upon start up.

I know that I should just bite the bullet- pull the head, replace the gasket, timing chain / tensioner and send the head out for a valve job while I am in there, but I am hesitant to do this for a couple of reasons.

1) it is not in my budget to drop 2k on a gasket, TC and valve job right now.

2) I don't have a mechanic I would really trust to do this right now. Anyone have a good one in San Jose?

3) I had some hope of doing the work myself, but given that this is my only car and I have not had to pull the head on a car in about 5 years, I am little gun shy.

Here are my thoughts. I know that the head gasket has a small leak at the rear (got to love the M104) and I am wondering if the leak has gotten worse and is now allowing coolant in the cylinder.

- How can I check this, short of draining the coolant and oil?
- Is it possible that a bad resevoir cap would allow some of the coolant to boil off?
- Is 1/2 a liter a reasonable amount to boil off over the course of a 250 mile, long hot drive with full AC?

What are some of my options?

Any suggestions would be welcome.

Thanks,
~dnm

[mark cummins]

You can Buy some Block check at the Local auto parts store that will test the coolant for Blown Headgaskit/Cracked head,block

Inspect the The Radiator cap seal and Spring If the seal is Shot/Dry or the Spring binds Replace the cap..It helps to pressure check the cap..But since you dont have a Cooling system pressure Pump ..I Would Just get a New MB radiator cap

The Cooling Syetem Should NOT be Down any amount after that drive Unless You have a Leak
You Should Try to see if you can Borrow a Coolant system Testor
many Auto part stores will Loan you one To test The System ..To help you find Leak.

[MikeTangas]

If you smell coolant coming from the heating/AC vents, I would suspect a leaking heater core.