Q: My 1985 Mercedes 300 SD is over heating and the new cooling system is only 6 mo old?

asked by on October 05, 2017

6 months ago I began to over heat a lot. I took my car to my mechanics shop where he determined I had a clogged hose and as a result I cracked my radiator. He replaced my radiator and clogged hose and restored the coolant.For 5 1/2 months it ran great. 2 weeks ago it began to overheat and i put water in the reservoir. It ran fine for 10 days. 2 days ago, out of nowhere my car shot to high 100 mark indicating I was overheating. I had only drove to the store and it happened on my way home. I have not driven the car since that happened 2 days ago. The car has more than cooled down, and i have a galleon of water I am about to pour into the reservoir. My question is.. What do you think the problem can be? Please note I owned my car 5 yrs & I drove the car 4 years without ever putting any water. Now I have a new cooling system that is 6 mos old and i am having issues. Also, should I consider adding radiator fluid again or what? My mechanic is on vacation and unreachable, what do you think?

My car has 125000 miles.
My car has an automatic transmission.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I use the steering wheel audio controls?
While you can use the buttons and knobs on the radio itself to change the station, cycle through tracks, adjust the volume and more, doing so while you’re driving can be very distracting, which is never a good thing. You...
Smart Entrance Control Module needs replacing
The SECM may be ok. It may have a power issue due to a blown fuse or relay. The SECM is an expensive part and may require factory level programming. I suggest having a qualified technician fully inspect your vehicle's...
Having problems accelerating at high speeds causing jerking feeling...this happens when slightly pushing gas pedal
This problem of a slight jerk feel is what is known as a lean tip in surge. The cause can be an indication that the engine is running lean and may be caused by dirty injectors, throttle body, air filter,...
Won't shift out of park 2000 Chevrolet Silverado 2500
Some vehicles have hidden shift lock solenoids. These are particularly on the vehicles that have a column shifter. It is possible that the steering column trim will have to be removed in order to access it. I would recommend having...
My car is spitting coolant from the overflow tank
Hi and thanks for contacting YourMechanic. Check the coolant strength to see what the protection is. A good protection will read 164 degrees Fahrenheit. Check the radiator cap to see if the seal is torn or if the release valve...
I replaced my battery now the starter motor makes a clunking sound and starts after a few tries
Hello there, many faults will cause your 2003 Land Rover Range Rover to take multiple tries to start. It is great you have already replaced the battery as this is a very likely cause in most cases. There are many...
how often do i change my oil
My service manual says to change oil and filter every 13,000 miles or 12 months. You should verify this in the owners manual and with a local dealer just to verify.
I start the truck it runs but has no power when I start to move
This kind of reaction is often a sign of low transmission fluid (https://www.yourmechanic.com/services/transmission-fluid-service) or a faulty transmission control solenoid. As you know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car's...
2007 terrible gas milage - replaced cylinder head - ignition coils - and soark plugs - I'd it worth it to replace fuel filter
Hello, thank you for writing in. The fuel economy is going to lessen over time for many reasons. If you believe there is something mechanically wrong with the vehicle, start by scanning the vehicle for diagnostic codes (even without a...

Related articles

A Buyer's Guide to the 2012 Mercedes-Benz GL-Class
In In the world of full-size SUVs, Mercedes-Benz has made a name for themselves by offering unrivaled luxury in a field where the size of the engine is often the most important metric. While the 2012 Mercedes-Benz GL Class definitely...
How to Source Parts For a Classic Mercedes-Benz
Classic Classic Mercedes-Benz cars are just as elegant and gorgeous as current model year Mercedes vehicles in many cases. There is a devout following dedicated to classic (https://www.yourmechanic.com/article/how-to-buy-restore-and-sell-a-vintage-car-by-jason-unrau) Mercedes vehicles who are passionate about the technology, styling, and responsive handling...
Industry News for Automotive Techs: October 22-28
Japanese automakers step up security, Mercedes' X-Class pickup, carsharing with Turo, VW TDI settlement approved, Faraday Future behind on payments.