MixwizardT

I have a 99 C230 that we've had since brand new - always serviced - all records - has 260,000 miles on it and has been a stellar car. It developed a small head gasket leak 8 months ago and after much soul searching it was decided that to replace the head gasket would spell doom for the car. After research I used K&W Fiberlock as directed in the cooling system and it worked great - no more leak - been driving the car everyday. Over the weekend, the car started to overheat, let it cool, added a little water and drove with the heat on to my destination. Replaced a faulty radiator cap and replaced thermostat. Drained the coolant and added a fresh batch of Fiberlock and a 50/50 mix. Car runs fine - but - it will only stay cool if I run the heater now - which sucks because I'm in Florida. As soon as I turn off the heater - the temp gauge start creeping up until I turn on the heater, then it goes back down. Does anyone have any ideas of why this is happening? the coolant is circulating and there are no visible leaks - no water in the oil - went 80 miles and lost maybe 16 ounces of coolant. topped it off hoping there might be some air trapped in the system, but same deal today. Fans are working correctly. Why won't the thing stay cool now? any ideas or help would be seriously appreciated

taz069

Some goo and bad news. I'm not very familiar with the 230. But your problem sounds so familiar as i had with my 96 c280(inline 6 m104). On the positive side you have had the vehicle since new. Here we go. If you already are experiencing a loss of water it will not get much better. With 260k miles on the motor now a head reworking will not spell doom for the car. A good valve job and a head resurfacing will reawakin some lost pep. If you are not mechanically inclined i personally would not tackle such a task. Now for the temp raise. In adding different stop leaks to the coolant system you are tasking the old radiator even further. I had a 30-40% blockage in the radiator alone. Not to mention when my head gasket did go it dumped water into the oil. The old water pump was on its way out also and mine only had 195k. I have done all the work to mine myself, and it has been a chore!!! New radiator, head resurface, valve job, water pump, water thermostat, ac comp and all other assorted peices and parts. Good luck and keep me posted. Also try club 202. They are a mercedes club for our model cars w202.

aquinob

Is the car still loosing coolant? If it isn't maybe as taz says, the radiator is plugged up and you need the heater core to remove the excess heat. You could try and replace the radiator and see if that fixes the problem.

Longer term, the car has 260k miles. You done a bandaid fix for the head gasket issue which may last a bit or it may get worse (probably). With that kind of mileage the car is probably worth a couple grand so what you have to figure out is if it's worth putting that much money into doing the head. Even if it gets you another year of use, you are probably ahead financially compared to the cost of car payments. Or you could look for another low mile car and go with that. I just picked up a 98 with 68k miles on the clock for 4 grand that I am in the process of getting cleaned up and road ready. Sometimes it does not pay to throw money in an old ride, but that is something you have to decide.