This is for my 82 240d - so no extra coolant reservoir. I did a citric acid flush last week. Now almost every time I drive my car, it leaks coolant via the overflow line anytime I stop. I could understand once or twice, but this has happened at least 6-7 times. I check the coolant after cooling down, and its always still full. I don't understand how I keep losing coolant but the radiator is still always full.

Could someone enlighten me on this?

Thanks!

It all has to do with thermal dynamics, and expansion/contraction of said fluids.

Also, check for a weak radiator cap. If the cap is good, then do a pressure test. Install a coolant overflow bottle using a 2 liter bottle until your system stabilizes. Trapped air some where can increase the internal pressure of the cooling system when at operating temp.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

If its just trapped air expanding and pushing coolant out, wouldn't it contract and lower the level when the system cools?

BTW, you did burp the system to get all the air out after the flush, right? And you did flush with clean water (and drain the block each time) several times to get all the acid out, right?

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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

It should, unless it's a trapped pocket, but even then ther is only so much coolant it could lose. That is why I suggested using a 2 liter bottle to catch the overflow.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Good idea on the 2 liter bottle. Now about the "burping" - what exactly does this mean? I drained the system, added the citric acid, drove around for 30 minutes, drained, filled up with distilled water, brought to operating temperature, drained again, did the same one more time, then filled with coolant/water. I did not do (or at least think I did not) do what you are saying is burping. What does this exactly do?

Burping eleiminates most of the trapped air. What you do is get the front end up as high as possible by parking on an incline, using a jack, or a combo of both. Fill the system from the upper radiator hose. Connect the rad hose to the t-stat housing, and fill from the hose. until you can't fill any more.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Thanks for the reply rrgrassi - but I do not 100% understand. Ok so this is what I need to do:

1. Jack car up (no hills around here in the desert lol).
2. Disconnect upper radiator hose and fill with coolant until no more will go in.
3. This is the part I dont understand - connecting the radiator hose to the t-stat housing - your not talking about the upper radiator hose right? Because that will not reach.

Make sure the upper rad hose is disconnected from the radiator, but connected and tightened to the t-stat housing. You will have twist the hose a bit to line it up so you can pour the coolant in.

Sorry for not being very clear. Got to bed too late last night.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Burping means getting out the air trapped inside the coolant system, but not in the radiator where you can see it. Good instructions have been given, and others are available -- I think I searched for "burp" and "coolant" to find them all a few weeks ago.

However, I'm more concerned that you may still ahve a significant amount of citric acid floating around in your coolant system. That would be bad over time. The instructions I've seen on the citric acid flush mention draining the block and repeating more than just two or three times. The idea is to get all the citric acid out so it doesn't keep eating away at the engine. If you don't drain the block, you'll need to flush more times to get the same residual concentration of acid in the system -- I'd guess around 5-10 times more should do.

Why am I concerned? Because as I recall, there's aluminum in the engine system that the coolant comes in contact with, and Al + acid + water + heat will dissolve the Al and produce Hydrogen gas.. so it could be a source of new gas in a coolant system. Of course, someone will correct me if I'm wrong about the Al or its reaction with citric acid

Is this what is happening in your system? I dunno. Burp it and, if you get more gas, and it isn't from a leaking head gasket (which is far more likely), then maybe its from some chemistry going on inside there.

__________________
'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

cool, thanks for the info. Ill try burping this weekend