89 300E coolant issue
 

My car uses oil like most other older cars - its an ongoing issue.

During a typical stop to put some oil I noticed my coolant level was right above the sensor. (too low)

Also noticed that the windshield water reservoir was leaking from one of the bottom connectors (right hand side) which has a hose that goes to left hand windhield wiper (headlight).

Windshield water reservoir liquid was hot.

Put some mbz coolant/water to proper level, and drove to my destination.

When i got there noticed the level for the coolant was once again low, and the car was still leaking from the water reservoir.

6hrs later when i checked the car (after being parked for that long) the coolant level was back to normal.

What I believe is happening is that for some strange reason, the coolant is making its way to the winshield water reservoir as it expands, and since the water reservoir is old (and possible not meant to handle hot liquid) it started to leak.

When the car has cooled down the coolant ens up back at the reservoir.

To resolve the leak I will need to replace the reservoir, but what about the issue of the coolant making its way to the windshield water reservoir?

Please advise.

I do not think the two reservoirs have anything to do with each other.

There is a heater in the washer reservoir and that is why it is hot.

On the coolant issue, I bet that you have a bad cap for the expansion tank. Spend about $5 and get a new one. If that does not solve the problem, it is still a $5 well spent because these caps are known to fail.

Yes, I was thinking they are not related.

However i think I am able to see coolant in the winshield water reservoir. mbz coolant is orange.

Any chance that something else could be faulty (i see a little motor looking thing to the right of the windshield reservoir with hoses that go to both cooland and windshield reservoirs any chance that maybe faulty?

I will replace the cap for the expansion tank in the mean time and will update on the issue afterwards.

Thank you for taking the time.

Washer fluid comes in many colors. If you empty the washer reservoir and put in the blue type, I guarantee you won't see anything orange. They do not share any of the plumbing.

Just get a cap and you are done. You can either go to the dealer or order online. Parts stores also carry a Stant replacement that works well. Do not forget to send a case of beer for this.:kid:

See you at the next " AA " meeting. :D

Manny:

Are we having fun or not, LOL? We nailed the too-long lugbolt in the other thread. I think the cap is his problem on this one.

Would that be the overflow tank cap, or the beercap? ;)

Well, overflow cap for him and beer caps for us.:laugh2:

The windshield washer nozzles are heated electrically, but the washer reservoir is heated by an exchanger with coolant flowing through it. It sounds as though it's allowing coolant into the washer bottle. You can replace it, or, bypass it, depending on your budget.

Thanks for pointing that out, MB Master.

I always thought that metal coil in the washer tank is an electric heater like the ones we use to boil a cup of water. Now after looking at my 1991 300E, I see it is a hot coolant heater. It looks like it is made of stainless steel and it is a one-piece part (so should not leak easily). I do not see any joints within the washer reservoir.

Where is the exchanger located, on the firewall by chance? I have a hose with a bolt on the end coming from a black three-way metal thing and I don't know what it is.

1988 300E

The exchanger is the coil in the reservoir which has hot coolant flowing through it.

I purchased a stant one (new cap) - pain on the neck to install/remove, a little tight 11235 i think its the number (perhaps I was given the wrong size one). I am just going to get the mbz one tomorrow.

The little motor is the auxiliar water pump and it does have hoses that go from the water reservoir (coolant) and to the coolant reservoir

Windshield Washer Heater
http://img.eautopartscatalog.com/live/thumb/P707473971OES.JPG

I think the issue may be that portion of the coolant does go into the washer tank. I did notice the other day that the level in the water tank rose.



Perhaps this other piece of information is related.
A while back the side ac/heat vents (next to the doors) were pushing hot air (with the AC/heat off). I did some tests and it appeared that could be that the mono valve was not working (which is by the battery) as a last resort prior to purchasing the mono valve I reseated all the fuses, and that took care of that, it seemed the valve started working again and no more hot air (even when the ac was off). I see that there is a plastic hose from the mono valve to the auxiliary water pump / washer tank.

So maybe related too?

heat exchanger makes sense. Can it just be bypassed for the time being?

by running using a hose (remove heat exchanger and just use a hose to plug both ends of the coolant lines)?

part is special order

It may be tricky to plug the holes in the WW reseviour... but with the rightr fittings... I'm sure you could bypass the exchanger.

Anyone know if the WW exchancer is relatet to the heat being on?