coolant level dropping - help please

[waterloss]

hi,
ive checked the forum before typing this...and I suspect a cylinder head or blocked rasdiator core??, but please read on and give me your opininon

merc 190e, 1.8, k reg, 82 thousand, allegedly well looked after, all the services etc.

runs perfect, no steam from exhaust, no oil water in oil or vice versa.

First thing i noticed (having just bought it!!) going up hill, coolant light comes on.... I inspect and top up thinking previous owner maybe never checked it.
I top it up to the level and drive to work a few times (100 mile of motorway a day) I find the level dropped by what turns out to be a litre every fortnight give or take.

Anyway, I take it to a specialist, who pressure tests the coolant sytem...nothing found, but suggests it could be boiling over the overflow??


now that I'm paranoid about it, i have noticed the overheating smell on parking up after driving any distance, that smell of hot radiator BUT no visible leaks or steam

it runs on the motorway at about 80 degrees (its winter though) in congested traffic it rises, but never to the fan starting. (I dread to think what will happen in summer)

Also, when in slow traffic at the end of the hundred mile or so i get a bit of a clutch judder at the bite point... the clutch getting hot?? (it never judders apart from after a lot of rush hour crawling along)

So all the symptoms of a hot engine, but the guage never gets that hot (its never been up to 100), but that overheating smell and coolant loss + the clutch judder has me worried.

have I bought a bad one?? or is this a quirk of the model?


I really can't face the six hundred quid bill I have been quoted for a cylinder head just yet (the specialist is convinced it isnt the head anyway, though he has only checked the coolant for visible leaks and pressure loss)

I need your advice guys.


thanks

 

[Richard Moakes]

Most likely the waterpump, the darn things stealth leak and you can't see where from without mirrors and torches etc...

Is the undertray damp in a morning? Mine used to leak as it was cooling down after a run.

Can't comment on the clutch, I hate them unless they are in sports cars!

Regards,

Richard
1989 W124 300E

 

[Matt Crooke]

One thing to check is the thermostat housing. The one on my 2.0 litre 190e had a hairline crack in it. It is very easy to break when you are tightening up the cover as its only made of plastic.

I only managed to find where the leak was coming from by leaving the engine ticking over and spotting the very fine jet of steam coming from the cover.

Have a check to make sure this isnt the culprit.

 

[Spike]

I had the exact same thing on my W124. There was a hairline crack on the thermostat housing near one of the screw threads where it screws down.

It was so small that it was only visible when you were really close & the engine was hot and then you could just see that coolent was bubbling around the crack.

The only symtoms I had was that I was losing coolent and the engine tended to run a little hotter than normal and the fact that every now and again the coolent light would come on.

My suggestion is that it may well be worth having a *really* close inspection of your coolent system while the engine is hot.


Oh, I have heard similar symptoms caused by a faulty radiator/expansion tank cap so for £5, it may be worth just buying another cap anyway.

 

[waterloss]

coolant loss - sorted!

Thanks for all your advice guys, after all the concern about the cylinder head it turned out to be three pin holes in the radiator!!!... leaking so slowly as they could barely be seen.

New radiator and a system flush and we are back in business!!



cheers

 

[mickyg]

It would seem that the people who did the initial pressure test did not do it correctly, otherwise they would have diagnosed the fault immediately

 

[Bob 2316]

hi waterloss
why a new rad? why not spend £4.49 on a bottle of Radweld first!

I did and it worked!

Bob