Recently I have been smelling coolant after driving my DiscoII and needing to add coolant to the reservoir tank to keep it full. The truck is not overheating nor running unusual in any way. Last week, after driving it for 45 minutes, I decided to watch for leaks. About 10 minutes after shutting off the engine I noticed coolant starting to drip from the vicinity of the front driver's side corner of the oil pan. I placed a small container under the truck to see how much coolant my Disco would lose, and I tried to pin-point the source, but I couldn't see anything helpful. (See attached pictures for location of drip and volume of coolant loss.)










Several days ago I ran the engine for 10-15 minutes on the driveway - long enough to heat up, but not near as long/hard as the previous trip. A few drops of coolant appeared at the same place, but nothing like before. I tested for any combustion gas in the cooling system (twice), and the test was negative. I removed the fan, auxiliary belt, and the pulley from the water pump and checked the coolant pump gasket and all hoses coming to/from the reservoir tank, thermostat, radiator, and water pump, but found no apparent signs of leaking.

I've cleaned-up the bottom of the engine/oil pan to, hopefully, make it easier to spot the source of the leak and plan to either drive the truck for longer or pressure test the coolant system to see if I can spot the source, but I was hoping some of the sages on here might be able to help me diagnose the likely cause of the leak before I start conducting exploratory surgery. I'm thinking one or both of the intake manifold gaskets?? I'd appreciate any help. Thanks in advance!

 

could be a lot of things honestly, I would pick up some of the coolant dye from the autoparts store and a black light. It almost always works to find the culprit.

 

When the engine cools down, grab a flash light and under the hood, look directly behind the water pump pulley, on the passenger side. If you look very carefully, you will see a small weep hole. Look for coolant drops in that hole. Then look to see if there is a trail from that point downward. I just replaced my water pump because of this leak.

look at the green dot in the lower right corner of the picture. That is what you are looking for. I would start there. Also, another place to look is under the throttle body where the air intake meets up. there are two small coolant hoses underneath and that gasket underneath is a common failure point and coolant leak,

 

Check the throttle body heater plate. You do not need to open anything to check it, just look under the throttle body for orange stuff. It will also leak on the driver's side valve cover.

 

All good suggestions, thanks.

Forgot to mention I changed the throttle body heater plate and gasket not-too-long ago, so it's nice and dry.

 

rent or borrow a coolant system pressure tester

 

None of the parts places near me had a tester for the expansion tank, so I bought this:


May save you some trips just owning one.

 

i bought one years ago from harbor freight, it gets used every oil change.
you would be surprise how much screw clamp loosen over time, ive go back to the spring clamps

 

That kit will not work on a DII. I found out the difficult way and bought the exact kit.

I ended up purchasing an Assenmacher Specialty Tools BMW 345 Radiator Pressure Adapter for BMW. It works on a DII tank. I found it on eBay for $19 vs $40 on amazon.

 

I have not used it yet. Is it missing the correct adapter for the expansion tank? Good find because I don't see any for under $40 online. Also, what pressure tester did you use with the adapter?
http://www.ebay.com/itm/Assenmacher-...-/331541729903