BetterDaze

Got a coolant light and when I went to top up I saw the leak immediately.it is a solenoid type of unit with a hose on both sides between the reservoir and engine sitting near wheel. Anyone know what it is?

LauraS

I believe its an auxillary small pump that circulates coolant through the heater core before the thermostat opens. My 190E interior warms up faster than any vehicle that I have ever been in because of this little pump. On a cold winter morning even at -30 heat starts coming through the vents within a kilometer of driving and sooner in milder weather.Since it will run with the engine shut off it will continue to provide heat.

190Efan

The leak might be small now but it'll only get worse until it gets fixed. It's probably the heater pump as Laura suggests but make sure it's not your radiator either. This is one of those things that you should fix sooner rather than later because you certainly don't want to run out of coolant as that could result in catastrophic engine damage. Be sure to use MB coolant and distilled water.

BetterDaze

Thanks Laura and 190efan, it is the auxiliary water pump didn’t know what to call it at first. It’s leaking at the top of the head and you can see a fresh stream of coolant in my pic. It’s been a few months since the last time I got a coolant light most likely from there, I didn’t see any leaks around the radiator.

i parked the car until I get that fixed, the leak will likely accelerate otherwise.

dolucasi

It looks like it has a gasket at the point of wetness. And it is put together with a few screws. Maybe serviceable by replacing the gasket.

BetterDaze

I’ll check with my indie tomorrow to see if there is an o-ring there they might have on hand.
im thinking I should just replace the pump though its probably OE from 87

dolucasi

Mine is still the original from '89. Probably on it's last legs too. I recall they were not that cheap but this would be a good time to replace iy. May go NLA soon, if not already.

BetterDaze

It was over 600 from dealer, they are now NLA and there is no internal seal. My indie says they can have it rebuilt by some type of Bosch specialist, they do some type of “modification” to it but that just seems like a pocket grab...$500? I’ll pass

Fcp euro and autohausaz has a Dorman and Bosch units but I’m not too sure if it is the same part they don’t match the part number (0008356964) I was given and don’t explicitly confirm if they fit the 190e. They seem to stretch across varying MB models and years

BetterDaze

AutohausAZ has limited stock on the part so I took the risk in case I can’t get another. The Dorman unit does say it will fit

dolucasi

Sounds like I ought to grab one from the JY. There is a smashed W201 in my local yard with ~120K miles on it. Good to have a spare. How much was the Bosch unit on FCP euro?

BetterDaze

$77 on FCP euro but it has conflicting fitment information. I got the one off autohauzs az for $180 since it gave a green check mark for my year and model.

I would grab that JY unit for sure, you can likely make a new gasket. I don’t really have time to take mine off and open it up, I have to daily the car for the time being.

dolucasi

Any reason you chose the $170 Dorman over the $74 Bosch unit at AutohausAZ? They both get the checkmark for the 190E.

BetterDaze

No reason other than it was too late to cancel my order when I checked again lol. Initially got confused when it was listing GL55 and other models too, i think it might be a “universal” part but it comes tomorrow


i can return it for my full refund and just got that cheaper one from fcp euro

dolucasi

Do let us know how it all works out.

190Efan

You need to park this car until you get it fixed. Continuing to drive it with a coolant leak that'll only get worse until it's fixed is risking serious engine damage if your car was to overheat.

BetterDaze

Thanks 190efan and dolucasi. Unfortunately I do have to drive the car since my daily one is waiting for parts too.

I check the auxiliary pump and coolant level everyday before I pulll off ,it is not rapid so I think it’ll be okay at least a week. I don’t drive much and avoid turning the heat on unless necessary. I’m scheduled for a coolant flush with my indie next week. After I put the new aux pump in, I will have them look it over for any additional leaks.

190Efan

Don't change your coolant until after you've changed your auxiliary pump because the coolant will just continue to leak out until the auxiliary pump is replaced. Again, if your car still has its original MB radiator, be sure to have your indie use only MB coolant and distilled water. Non MB coolants seriously damage the plastic interior of MB radiators. My engineer father always taught me to use distilled water to lessen the chance for rust to form inside the radiator which can cause the radiator to fail.

LauraS

Mercedes coolant is no doubt a good product but I think others are as well. I cannot buy MB coolant because there is no source less than 700KM away unless I pay shipping. My 190E only had MB coolant for the first two years after I bought the car. My husband replaced it with other brands mostly Havoline and Havoline as I recall. The last two changes since I have been alone has been Zerex G-05 which, I understand meets MB standards. I also mix it 60 % antifreeze/40% distilled water because I need protection down to -50C on rare occasions. The important thing to do is change it every 2 years like my husband did. He didn't trust the 5 year life claims. I agree with 190Efan regarding distilled water and wait to install new auxillary pump. Both are good advice.

190Efan

Laura, Thanks for the kind words. I'm really glad for you that you haven't experienced the damage to the plastic interior of your 190E OEM radiator that non MB coolants are known to cause and I hope it stays that way for you. I also certainly understand and am sympathetic to the distance issues you're dealing with in getting the parts/fluids, etc for your 190E. I've also read too many horror stories on various online MB forums over the years that have documented this particular coolant issue in great detail. This is why I still say that for owners who still have their original MB OEM radiator and are near to MB dealerships, it's still best to use MB coolant due to all of the documented horror stories of using non MB coolants.

LauraS

190Efan, I could not agree more. The best choice if available is OEM Mercedes Benz. I did replace the thermostat housing from the plastic version that came with the car to the aluminum one just as a precaution not because of any leaks. The inside of the housing and the thermostat, which I also changed, looked as good as new with no deposits showing. I don't think any coolant could do a better job than that in a 33 year old car. I trust Zerex GL-05. Your comments and advice are valid.

BetterDaze

I finally got the new aux water pump in today and the hardest part of the job was getting the corroded electrical connector off, the part on the pump itself actually broke and I had to pull the wires out with small grips.

I lost a decent amount of coolant do I need to let it run,burp the system and top it up a little or just leave it alone until my coolant change appointment

dolucasi

Well, at least you did not have issues with fitment it seems. Was it the Dorman unit you ended up with?

BetterDaze

I used the Bosch one.

The original one(also Bosch)on the car did have a bracket for the electrical connector that kinda folded underneath. the new component doesn’t need it so the cord is slightly longer but yeah no fitment issues

190Efan

How much coolant is still left in the car?

BetterDaze

It was pretty low afterwards just above the bottom outlet hose. You can save more if you pinch the hoses but I didn’t want to risk damaging mine.

before driving it, I did let it run with the top off the coolant reservoir to let the coolant recirculate and any air bubble out then topped it up to get the light to go off. I didn’t let it get anywhere near operation temp. My indie has it now though