Need Coolant Help

[JoeMB]

Today I replaced the radiator hoses, heater hoses, and thermistat on my 1984, 300D Turbo. After checking all the connections I refilled the coolant resevoir (there is no actual cap in the radiator) and restarted the engine. I soon realized that there was no coolant going throught the radiator or heater hoses.

There must be an additional way to refill the coolant that I don't know about. Can anyone give me some advice on what I should do?

Thanks

[gdaley]

I have done this on many different vehicles. A good clue is the system being full when you've only added, say, half what it should hold. Often the cause is the thermostat being airbound and refusing to open because it isn't immersed in coolant, just slowly heating by conduction, or radiation when the thermostat uses the rubber perimeter seal common on many makes. Bmw's often have an air bleed at the top of the radiator and Saabs have a bleed nipple on the thermostat housing. A good shop manual will have this info.

Several years ago, I was mystified by "The Puzzler" on Car Talk. I know their true profession is being comedians but it can be quality amusement. I missed the following week when the answer was revealed but thought about it several times. The answer finally came to me several weeks ago. The scenario was an old-timer replacing a thermostat. Another mechanic saw him open a bottle of aspirin and asked him what was hurting. He replied that he needed it for the job. Why?

He put a couple in the thermostat to jamb it open. This lets air past preventing airlock and they dissolve the moment coolant touches them. I will try this next time I replace the coolant on my Volvo, the most recent airlock victim.

Good luck!

Hi,
When I refilled the coolant in my car. I poured it in the
thermostat hole in block and radiator hose. Put thermostat back in. Started car up and put the leftover in the coolant
reservoir. Sounds like your closed thermostat will not
allow coolant into radiator and block until it opens.

I did not want to risk not having coolant to water pump
so I did it this way. Also put car on a incline just
to try to minimize trapping any air.

Hope this helps,
Gary

[gdaley]

Try loosening the highest hose clamp in the system to let some air out. Otherwise drain it and refill it very slowly. This minimizes the probability of airlock occurring.

Joe,

I went through this before with the same model car. Your problem may not be the same, but I'll let you know what happened to me.

My wife bought a used 300D turbo. Everything was fine 'til I had to put a monovalve kit in and lost some coolant. There are two hoses from what you're calling the reservoir to the radiator. This is not really a reservoir, it is the top tank for the radiator just relocated. The top hose is small and goes to the top of the radiator for a vent between the two. The bottom hose is the main hose.

On her car, someone had removed the top hose and plugged it off. You could not completely fill the radiator. The plastic fitting for the small top hose was broken off the radiator. I used a metal valve stem that is used on aluminum wheels. It is threaded with a nut and two rubber washers. I put a piece of wire through the radiator top hose connection and through the small hole and pulled the fitting through, then put on the nut. I then put the vent hose on this and all was well.

I doubt that your vent hose is gone, but it should be clear.

As I said this is probably not your problem, but definitely see that the vent hose is clear.

Good luck,

[JoeMB]

I want to thank everyone for their input. What I finally did was loosen the top radiator hose and poured in coolant then quickly reattached the hose. Then filled the resevoir. I started the engine and followed the instructions in the shop manual. The thermistat finally opened and coolant started going through the heater hoses.

Thanks Again,

Joe

Joe,

Was the small vent hose at the top okay?

Have a great day,

Did you turn on the heater when refilling it the 1st and 2nd time? You might notice still a drop in coolant level in about a week or so.