If your engine is just running hot, it may be due to a plugged radiator or possibly a stuck thermostat. If your engine is just losing coolant it could be a leak in the water pump, radiator or hoses. But, if an engine is running hot and losing coolant at the same time, it is a good indication there could be a serious problem and it should be checked into right away. Just don't keep driving the car or you can ruin the engine.
Product Details
In this video Kent will walk you through some of the basic tests you should perform when trying to diagnosis this type of problem. Please keep in mind this is a diagnostic video and does not contain any step by step details of the actual testing or of making actual repairs. Using an example of a 300D he will show you the results of doing a cooling system pressure test as well as a cranking compression test. Detailed instructions on how to do these tests are NOT included in this videol You will get to see first hand what happens if you try to use block sealer or just keep dumping straight water into the engine. At the end of the video you will learn what the tests showed and what will have to be done next - including some of the parts you should order if you plan to remove the cylinder head for further diagnosis of the problem.
Related Repair Details NOT included: No actual repair work is covered in this video. This covers diagnosis only.
Chassis/Models Used in Production: 1982 300D
Applies to the Following Chassis/Models: Applies specifically to all diesels but also indirectly to gasoline engines as well. Both types of engines can suffer from the same symptoms caused by similar problems.
Total Run Time: 9:14
See related products below for a sample of resources we carry to help with engine overheating problems.
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Important note: This video manual may or may not include all the information you will need to troubleshoot and/or repair your specific problem/s. Please read the full description carefully to determine if this video is applicable to your year and model and contains the information you are looking for. If not, please refer back to our "Solutions Finder" and enter your chassis number and the specific problem you are having to see if we offer a solution.
Related Products:
Part 2: Diesel Buyer Beware - Cylinder Head Gasket Failure and Removal Woes - On Demand Video
When an engine is both overheating and losing coolant, you first want to exhaust all possibilities that the cause is something simple or inexpensive to repair. It is possible it might just be a stuck thermostat with a faulty water pump leaking coolant at the same time.
602 603 Diesel Engine Coolant Thermostat w/ INSTRUCTIONS
New Behr thermostat 80 degree C with gasket. Comes with illustrated installation tips. Instructions are specific for early 603 engine 1986 and 1987 but will apply to other models as well (some specific details may not apply to the later models).
Fits the following models:
201 124 Chassis 190E 300E Thermostat Kit
New Behr Thermostat and sealing ring rated at 87 degrees C. Correct fit for all 201 and 124 chassis 4 and 6 cylinder gasoline engines from 1984 to 1993. Most thermostats only operate at peak efficiency for few years and should be changed for optimal engine performance.
115 116 123 126 Diesel Thermostat Installation Kit
Fits 115 116 123 and 126 chassis diesel engines, non turbo and turbo, to 1985. This includes the 220D, 240D, 300D 300TD wagon and 300D/300SD turbo engines. Most thermostats only last a few years and should be changed for optimal diesel performance.
W107 W126 Chassis 380 V8 Engine Thermostat and Short Hose Replacement Kit
Brand new thermostat, heavy-duty short hose, and 2 new clamps. Fits all 126 Chassis 380 engines from 1981 to 1985 both in 107 chassis and 126 Chassis. Free Video installation tips included ( click on the arrow in the center of the picture to watch below:
115 123 300D 300CD 300TD Non Turbo Cylinder Head Gasket Set
New OE Reinz head gasket set. Fits all 115 and 123 300D 5 cylinder non-turbo engines 1975 to 1981. Comes complete with all gaskets only as shown in the picture. Valve stem seals and valve cover gasket are NOT included.
115 and 123 4 Cylinder Head Gasket Set
New OE Reinz head gasket set. Fits all 240D 1974 to 1983, 4 cylinder diesel. Comes complete with all gaskets only as shown in the picture. Valve stem seals are included.
603 6 cylinder Head gasket Set
Brand new Head gasket set for 6 cylinder diesel engines from 1986 to 1987. Does not include valve cover or valve stem seals.
617 Turbo 5 Cylinder Diesel Head Gasket Set
New head gasket set. Fits all 5 cylinder TURBO diesel engines only from 1978 to 1985 including 300D, 300CD, 300TD and 300SD. Comes complete with all gaskets only as shown in the picture. Valve stem seals, chain tensioner gasket, thermostat housing gasket, and valve cover gasket are NOT included.
616 617 Diesel Water Pump Installation Kit w/ Limited Instructions
8/2022 Update: We have modifed a new wrench for this kit so it may not look the same as that shown in previous YouTube videos, but it will do the same or even better job! We do sell the water pumps individually, but we decided to offer this complete kit to make a diesel pump installation go easie
602 603 Five and Six Cylinder Diesel Engine Water Pump
New heavy duty water pump complete with gasket that fits all 190D 2.5, 124 chassis 300D, 300TD and 300D 2.5, 126 chassis 300SDL and 350SD and SDL, and 140 chassis 300SD and S350D. No instructions at this time.
Diesel Engine Water Pump w/ Limited Instructions
Here is another diesel item I strongly believe should be replaced as a preventative measure. Water pumps do not last forever and when they go, it is usually when you are on a trip - right? I feel they should be changed every 100,000 miles.
All 61x and Some 60x Diesel Engine Compression Tester Kit With Test Guide
For use on all*** Mercedes diesels 1959 to 1993. BUT PLEASE NOTE THERE ARE SOME LIMITATIONS ON THE LATER MODELS. Test compression on 110, 115, 116, 123, 126, 201,124 AND 140 chassis. Almost ALL models up through 1987 can be tested through the fuel injector hole.
615 616 617 Diesel Valve Adjusting Wrench Kit - Designed by Kent Bergsma - Made in the U.S.A.
These wrenches are fantastic labor savers. If you have been thinking about adjusting your diesels valves on your own - this kit will save you time, frustration, and high shop labor costs. Now is the time to get your own pair. NOW WITH RUBBERIZED GRIP HANDLES. Made in the U.S.
240D 300D 300SD Diesel Engine Short Hose Kit
Fits 116 123 and 126 chassis diesel engines from 1977 to 1985. This includes the 240D, 300D, 300TD and 300D/300SD turbo engines. This short coolant hose is located right below your engine thermostat housing. Replacing it requires removal of the thermostat housing from the cylinder head.