Welcome Guest [Log In] [Register]
Photobucket
Welcome to Mercedes-190.co.uk

We are the Mercedes 190 owners forum, the place to be for all owners and fans of the Mercedes 190E, 190 and 190D cars. Including Cosworth (2.3 16v and 2.5 16v), EVO 1 and EVO 2 models. Modified and concourse, track cars and daily drivers, all are welcome.

This free UK based forum was started back in November 2005 to serve the Mercedes 190 W201 community and now has over 9000 members from all around the world and 600,000 + posts.

The members welcome you and encourage you to stay a while and have a look around.
We offer you friendly chat and access to some very useful information as well as tutorials with photos and videos for many common repair and maintenance jobs.
Whatever your needs there is a good chance you will be able to find what your looking for. Such as our Mercedes 190 buyers guide

Sign up to gain access to all areas including for sale / classified areas and country wide meetings and events. Many forum features and sections are only available once you sign up.

Join our forum at mercedes-190.co.uk!

If you're already a member please log in to your account:

**New members signing up**
please check your junk mail for the email authorization email
otherwise we cannot verify your new account.
I have noticed a lot of unauthorized accounts in the system.
Regards
Admin

Username:   Password:
Add Reply
Coolant loss; Can't see where it is leaking from
Topic Started: Mon Jun 26, 2017 7:59 am (455 Views)
nullogik
Member Avatar
More than part of things
[ *  *  * ]
My second LE (#2) is loosing coolant. There are no obvious drips coming from the water pump or radiator area and the expansion bottle is free from leaks and is not overflowing when the car is at operating temp. I've purchase UV dye and looked all around the engine from above but can't find the leak. However, if I leave the car sitting after having had a run say, overnight, the following morning there is dry puddle of coolant (bright green from the dye) alongside the front wheel. The undertray also appears to be dry and there is no trace of green dye on it so it must be leaking from somewhere that is managing to bypass the tray.

So the leak is only evident after the car has been sitting for a while and doesn't drip (or its not obvious) whilst it is running and when it does appears to drip past the undertray. Does anyone have any ideas?
Edited by nullogik, Mon Jun 26, 2017 8:10 am.
Offline Profile Quote Post Goto Top
 
aimlessrock
Part of things
[ *  * ]
I would start with a careful check of all hoses, I was having a coolant loss issue a few years ago and eventually traced it to a pin hole leak in the top hose.
Offline Profile Quote Post Goto Top
 
nullogik
Member Avatar
More than part of things
[ *  *  * ]
Thanks, coincidentally I discovered yesterday on my other LE (#1) that the top hose is leaking and dripping down and accumulating on top of the water pump! There is green "crusty" coolant around the clamp and joint at the thermostat end and its dried as white powder on the water pump. Will replace that asap as I don't want a blown hose in this weather!

But there is no sign of crusty coolant or obvious drip/run marks from this pipe on LE#2. Although it could be a another hose as you hint, perhaps one of the lower ones - I've only been checking from above since I don't have a ramp.
Edited by nullogik, Mon Jun 26, 2017 8:12 am.
Offline Profile Quote Post Goto Top
 
aimlessrock
Part of things
[ *  * ]
you wil likely have to remove them all to properly check - it's the only way you can be sure. If this is a keeper I would've inclined to replace the lot for piece of mind. Be methodical and you will find it. Have you checked the heater valve btw?
Offline Profile Quote Post Goto Top
 
Toff190
Member Avatar
190 Mob Member and a Wise Guy.
[ *  *  *  *  *  *  * ]
Have you done a pressure test? Has the head gasket ever been replaced?
Offline Profile Quote Post Goto Top
 
JustbeCoz
Part of things
[ *  * ]
Water pump front seal area commonly has a small hose fitted as a remote drain. Do you know where the end of that is as it may be routed to clear the undertray.
Also heater matrix side connection o-ring fittings can leak under front carpets which may find a way to drain behind front wheelarch.
Offline Profile Quote Post Goto Top
 
nullogik
Member Avatar
More than part of things
[ *  *  * ]
Aimlessrock - I think that is a good idea. The rubber is 24 years old. A 30 degree summer day is not the ideal time to have a blown hose!

Toff190 - The head gasket was replaced about 3 to 4 years ago by a very reputable specialist with MB parts. The car has done, perhaps, about 3000 miles since then. The coolant loss has only occurred in the last 3 months or so. When the HG went there was plenty of gunge in the coolant expansion. I have kept my eye on it since then and the coolant is clean with no oily residue or gunge evident.

JustbeCoz - I had experienced this with LE#1 which had a drip from the water pump overflow hose. The drip was obvious with that car i.e. steady drip when running or parked up. With LE#2 the hose seems dry. There was a slight green residue under UV light when I stuck my finger up it, but I don't know if that is contaminant from oil/gunge prior to the HG change. It appears that engine oil also fluoresces green under UV light so it might be old oil and not dye from the coolant bottle.

I have just checked the car and thankfully the carpet in the footwells are dry. Could the matrix leak without fluid entering the car?
Edited by nullogik, Mon Jun 26, 2017 10:39 am.
Offline Profile Quote Post Goto Top
 
Will
Member Avatar
Highly Addicted
[ *  *  *  *  * ]
It might be worth taking it to a garage/specialist with the correct kit to pressure test the cooling system. If it's leaking coolant you should be able to find it quite easily.

Could well be related to the previous head gasket repair - either a part that has been disturbed/stressed during the dismantling/rebuild or rubber hose may have become damaged due to fuel/oil contamination and or excess pressure/heat. As said already, the hoses (and the rest of the cooling system components) will be circa 25 years old now.

You sure it's not something simple like the radiator (?) - either the rad itself or one of the hose connectors or th drain tap.
Offline Profile Quote Post Goto Top
 
Toff190
Member Avatar
190 Mob Member and a Wise Guy.
[ *  *  *  *  *  *  * ]
If the head gasket has been done then it's highly unlikely to be the problem.

So only loses water when cars been sitting unused for a few days ?
Offline Profile Quote Post Goto Top
 
mxfrank
Part of things
[ *  * ]
Although disappearing coolant MAY indicate a leaky head gasket or cracked head, it's best to eliminate the simpler causes. There's an overflow bottle hidden inside your fender. It looks something like this:

http://www.coolcatcorp.com/190Restoration/Mercedes25.jpg

When the coolant expands, it goes into the bottle, and is drawn back when the engine cools. But that depends on the expansion tank being air tight, the hose being in good shape and the cap not having some sort of defect. If either of these conditions isn't correct, fluid will "disappear" into the overflow bottle until it fills and overflows into the wheel well. A common cause for this condition is the filler neck becoming loose in the header tank casting.
Edited by mxfrank, Tue Jun 27, 2017 1:09 am.
Offline Profile Quote Post Goto Top
 
nullogik
Member Avatar
More than part of things
[ *  *  * ]
Finally managed to catch it leaking. There is slight drip off a pipe that runs in the wheel well behind the front wheel. That pipe looks like it doesn't carry coolant so I imagine it is tracking from somewhere else, running along the outside of the pipe before dripping on to the ground. The car was parked on a street tilted towards the passenger side so it could possibly originate from the driver's side.

As the leak is coming from the rear of the engine compartment does this point to it being a leak from the heating system? I've checked the under the mats inside the car and it is dry. I think the leak is coming from the space occupied by the wiper motor/blower motor.

Posted Image
Offline Profile Quote Post Goto Top
 
nullogik
Member Avatar
More than part of things
[ *  *  * ]
Decided to have a thorough look yesterday and found the leak. Dripping from the heater valve was coolant containing the dye I had purchased. I wouldn't have found it had it not been for the nbirhgt green dye in the coolant.
Offline Profile Quote Post Goto Top
 
ConorD
Claiming Newbie status still
[ *  *  * ]
That's a good find, and thanks for posting it.
I always thought that any fluid coming behind the wheel well was from the drains at either side of the bonnet.

I had a tiny leak from the top hose at the point that it joined the radiator sleeve - probably just a hard crust between the sleeve & the hose. I never would have seen it if I hadn't had the bonnet open and spotted a drip on the drain point off the lower side of the radiator. It evaporated quickly. But it was just a drop as the engine cooled; no noticeable coolant loss over months of use.

If it had been a problem, yet always evaporating, the only systematic way to spot it would be your dye + UV light idea.
Best Regards,
ConorD
Offline Profile Quote Post Goto Top
 
lowman
Part of things
[ *  * ]
Good thing you found it..but it wouldnt have taken longer until today..cause i was gonna suggest this valve to you:) ..as it is a very common fault to leak from the heater changeover valve.They are weak by design,and is a very neglected part to check when having a coolant loss.
The new types as slightly different in design,,but i guess they will start to leak over time aswell..even though different design.
While you are at it..make shure the vacum connection to this particular valve is in good condition,and that the rubber connector does have a tight fit.
Good stuff you found the leak on your car :)
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Engine · Next Topic »
Add Reply


Email me if anyone replys