Water problem??

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
I have changed my water pump on my E300TD 1999 recently and it has still been loseing coolant somewhere...i have noticed that the coolant is being forced back through the Expansion bottle cap for the radiator, i checked the cap and it seems okay but i have ordered a new one from Merc...is there anything else i could check/change to solve this...could the thermostat be at fault?? not opening....any help or suggestion would be appreciated thanks
 

rpe2

Senior Member
Joined
Sep 25, 2006
Messages
2,863
Reaction score
2
Age
44
Location
Silchester
Your Mercedes
His: 2018 E220 d; Hers: 2016 SMAX
Ask a garage to put a CO2 detector under the rad cap, will rule out a duff head gasket.
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #3
that will be next port of call i think.....thanks
 

wireman

Senior Member
Joined
Sep 20, 2005
Messages
2,632
Reaction score
3
Location
lancashire
Your Mercedes
nice 201 2.5D 1993 & very nice 129 SL500 1994
Old caps do develop slow leakage, due to the rubber washer going soft.
With luck replacing the cap should fix it or at least help.
 

grober

Senior Member
Joined
May 15, 2002
Messages
2,945
Reaction score
26
Location
Scotland
Your Mercedes
W204 C200cdi estate
Did you have a "water pump incident" when it failed i.e. did the engine overheat/ If so sorry to say this might be CHG failure.
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Or water pump as 230K posted elsewhere,,with the thermostat off you can check
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #7
Did you have a "water pump incident" when it failed i.e. did the engine overheat/ If so sorry to say this might be CHG failure.

No the car didnt overheat at all when i changed the pump it was okay at 80c temperature, it was grumbling and i did feel a little water from the pipe underneath the pump and just assumed my water leak was being caused by the pump failing as my car has done 160k and it looked as if it was still the original pump...but it seems the water was leaking back through the expansion bottle...i then changed the thermostat from the original complete unit after some good info from Television and got the new seperate housing and thermostat from merc and fitted this last week but it still has not cured it...pipes at the top and bottom are hot after a drive up to temp 80c on dash but do feel solid full of high pressure and when i do try and release this through unscrewing cap carefully it seems very excessive...when cold the pipes return to normal soft feel and can be squeezed although the top one feels empty...i cant think of anything else to try i have taken of thermostat and blown through pipes to check foe any blockages etc ....i have a new cap on order so if this dont fix it it looks like i will have to put it into merc or a descent independant.........it has been suggested the head gasket has gone..no water in oil and no white smoke from exhaust i can notice it has me stumped...unless as a friend suggested the water pump is faulty how can i test it without changeing it no water is being lost from the pipe underneath....sorry for the longwinded reply/explaination..oooooo:confused:
 

grober

Senior Member
Joined
May 15, 2002
Messages
2,945
Reaction score
26
Location
Scotland
Your Mercedes
W204 C200cdi estate
Get a garage with an exhaust gas analyser to sample the headspace above the coolant with the engine warmed up. It will pick up traces of exhaust gases entrained in the coolant. Its a very sensitive test. If this is positive its time for an individual cylinder compression test which will possibly help locate the origin of the leak. Then its head off time.
There is really no way to check the water pump except by visual inspection for leaks.
 

drmw

Moderator
Joined
Nov 25, 2007
Messages
3,740
Reaction score
155
Location
Yorkshire
Website
www.autonomed.co.uk
Your Mercedes
M6 Cab - prior to that, SL63 AMG, A-M V8 Vantage, SL55, SL500 and many more
I have changed my water pump on my E300TD 1999 recently and it has still been loseing coolant somewhere...i have noticed that the coolant is being forced back through the Expansion bottle cap for the radiator, i checked the cap and it seems okay but i have ordered a new one from Merc...is there anything else i could check/change to solve this...could the thermostat be at fault?? not opening....any help or suggestion would be appreciated thanks

Not sure I understand this - if water is being forced into the expansion tank I would have thought that pretty normal particularly with all the work just gone on until things (literally) find their own level - so if we have an expansion tank not bereft of water, no steam from exhaust, no water in oil, pipes under pressure, temp gauge showing 80c what indicates there's a leak??:confused:
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #10
The water is being forced back through the cap on the expansion tank and out the hose on the expansion tank from high pressure.. thus triggering the warning lamp on dash for low coolant level...my wife had to put in nearly 2ltr bottle today to top this up it was okay on Sat
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
at risk of suggesting the obvious, is the system bled properly?
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #12
Yes i did bleed the system too ......and tonigh i drove the car with the cap loose and it lost over 3 litres with it coming back up out of bottle..it was my understanding that if the cap was loose no pressure would be present and the level should stay the same ??...but it aint happening...could the pump be fitted wrongly?? or goosed although its new...when the water bottle is topped up and the car started the level does not drop at all and i thought it would eventually after a couple of minutes the water level rises eventually pour out over the expansion bottle??.........:confused::confused:
 

47p2

Senior Member
Joined
May 3, 2006
Messages
3,582
Reaction score
4
Location
Scotland
Your Mercedes
Slk
The reason that the system is under pressure is to allow the water to reach the running temperature without boiling over (pressurised water has a higher boiling point). With the cap loosened it will inevitably boil over and come out at the weakest point (the expansion bottle).

My guess is that it has either a bad airlock or HGF
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #14
just out of curiosity what is the recommended way to actually bleed the cooling system ???
 

rpe2

Senior Member
Joined
Sep 25, 2006
Messages
2,863
Reaction score
2
Age
44
Location
Silchester
Your Mercedes
His: 2018 E220 d; Hers: 2016 SMAX
rad cap off, heater to hot, run engine, squeeze the hoses now and again.
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Only squeezing the bottom hose to bleed.

You could remove the thermostat and put your finger in to see if the pump impeller is loose of turning.

If the pump was fault i would have thought that it would have boiled up,,if the water comes out before it is up to temp then the head gasket must have failed and it blowing the water out
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
often, if a head gasket is at fault, if you remove the cap, start the engine and rev it up a little. the level should drop a little and stay down. if it starts to rise again, and your sure its correctly bled, then its a head gasket failure. does it misfire on startup, as a matter of interest? especially first start of the day?
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #18
Only squeezing the bottom hose to bleed.

You could remove the thermostat and put your finger in to see if the pump impeller is loose of turning.

If the pump was fault i would have thought that it would have boiled up,,if the water comes out before it is up to temp then the head gasket must have failed and it blowing the water out

Im of thurs/fri this week so i will take out thermostat and have a feel about:D see whats what with the impellar
 
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #19
often, if a head gasket is at fault, if you remove the cap, start the engine and rev it up a little. the level should drop a little and stay down. if it starts to rise again, and your sure its correctly bled, then its a head gasket failure. does it misfire on startup, as a matter of interest? especially first start of the day?

The car starts great no missfires, lack of power etc all is as it should be run perfect from cold right up to temp 80c in around 3-5miles give or take a mile or two depending on outside temp...its not been used today so i will go out now and try what you suggest with the cap of etc

been and done it the water dropped...stayed there mabye minute then started to bubble with air coming back up left it like that for 10 mins squeezeing bottom hose to force air out...topped up and also fitted anew expansion bottle cap...will see how it goes tommorrow......
 
Last edited:
OP
S

StuggyZX10

Active Member
Joined
Jul 14, 2007
Messages
44
Reaction score
0
  • Thread Starter
  • Thread starter
  • #20
Just a follow up to my problem...its been over a week now since i changed the expansion cap for a new one and took the advice of a couple of member and bled the water system as advised.....and touch wood it has not leaked any water i will keep my eye on level for now ...but thanks again to all who responded to my plight thanks again..
 

You lost your key ? Or maybe you need a spare! Your vehicle imobilliser does not respond anymore? WE CAN FIX THEM ALL !! Mobile ! Save Time and Increase Profits With us !
Top Bottom