Losing water from the rad??

[Crapshot]

Hi folks. This has got me stumped a wee bit. Fill the rad up and drive for a week, say anything from 40 to 150 miles, look in the bottle on the top of the rad and the water level has gone down, never had the rad empty though?. I cannot find a leak anywhere. All hoses, water pump etc are all ok. Warning light never comes on an d temp gauge stays where it is meant to stay after a 75 mile drive. Is it possible there is a "pin hole" leak in the rad? Water doesn't come out when engine off and as I say, I cann't see a leak anywhere with engine running. Newbie question time. IF there IS a small leak in the rad, can I use Radweld in this engine to seal it? Book of words says to never add anything to the petrol (Redex) OR the cooling system "radweld?) as it might possibly, maybe damage the engine.

Cheers.

John

 

[Charles Morgan]

Heater matrix could be leaking - check your front footwells for dampness.

 

[brucemillar]

When you say loosing water. Do you mean that the water level in the header tank drops when cool? If yes? Then that is normal. Check it by looking when hot. It should be at or near Max. It will then lower as the car cools and draws it back into the rad. As it beats again it will expand back into your header tank and rise to Max. If low when hot you may have a leak.

Sent from my iPhone using MBClub UK

 

[Crapshot]

Heater matrix could be leaking - check your front footwells for dampness.

Have done that. All seems dry Charles. Then again, it has been wet since I got the car in November and I don't think the foot wells have had a chance to dry properly

John

 

[Crapshot]

When you say loosing water. Do you mean that the water level in the header tank drops when cool? If yes? Then that is normal. Check it by looking when hot. It should be at or near Max. It will then lower as the car cools and draws it back into the rad. As it beats again it will expand back into your header tank and rise to Max. If low when hot you may have a leak.

Sent from my iPhone using MBClub UK

I opened the tank when the car had been running for a short while? Not when the car was up to proper temperature? Better do it when it has been run for a distance and got HOT. BUT, wait for it to cool a bit before opening it!!

John

 

[Crapshot]

Oh NUTS!!!!!!!!!! Just made a newbie mistake guys. I have already put coolant in the rad and it went down? As far as I can see, there is a wee plastic bit that sticks out in the neck of the bottle that is over the rad? I am assuming this is the fill point? Have filled to there and after said driving, the level is down, hence why I say a leak somewhere? (Doh!)

John

 

[Dec]

Do you have a sealed or non-sealed system?
Sealed system has a tank beside the fuse box… https://www.google.ie/search?q=w202...ut7Abu0YCgDg&ved=0CAgQ_AUoAQ&biw=1265&bih=819


Non-sealed system has a small overflow hose running down the right side of radiator about 2 ft long, pointing towards the ground.

Dec

 

[Crapshot]

Do you have a sealed or non-sealed system?
Sealed system has a tank beside the fuse box… https://www.google.ie/search?q=w202...ut7Abu0YCgDg&ved=0CAgQ_AUoAQ&biw=1265&bih=819


Non-sealed system has a small overflow hose running down the right side of radiator about 2 ft long, pointing towards the ground.

Dec

Hi Dec. Non sealed. I have a black plastic "tank" on top of the radiator? Seems to indicate that this is an early 1996 model as well.

John

 

[Giantvanman]

Oh NUTS!!!!!!!!!! Just made a newbie mistake guys. I have already put coolant in the rad and it went down? (Doh!)

John

The first step in addressing a problem is acknowledging it!

Filling should always be done from the expansion tank which has the 'Fill to here' mark/line.

 

[Dec]

Hi Dec. Non sealed. I have a black plastic "tank" on top of the radiator? Seems to indicate that this is an early 1996 model as well.

John

You probably don’t have a leak, what’s happening is that when you top up then drive until hot, water expands and is over flowed on to the ground, you don’t need to keep toping up, if you do it will just over flow again.

To prove the point, tape … somehow… an empty coke bottle into the end of the over flow tube, this will collect the over flow water/coolant, don’t make the tube and bottle airtight.

Dec

 

[Crapshot]

You probably don’t have a leak, what’s happening is that when you top up then drive until hot, water expands and is over flowed on to the ground, you don’t need to keep toping up, if you do it will just over flow again.

To prove the point, tape … somehow… an empty coke bottle into the end of the over flow tube, this will collect the over flow water/coolant, don’t make the tube and bottle airtight.

Dec

You are wonderful Dec.......May I bow to your superior knowledge . I never even began to think about doing that!!

John

 

[Dec]

I was in the same position as yourself with my old W202 so I know how you are thinking, I was topping it up for a few days and couldn’t figure out where all the coolant was going, I stoped toping up for a few more days and it was grand, never got hotter than the usual bit over 80c so I concluded it was normal. I never did try the bottle thing to test.

Dec

 

[Crapshot]

I was in the same position as yourself with my old W202 so I know how you are thinking, I was topping it up for a few days and couldn’t figure out where all the coolant was going, I stoped toping up for a few more days and it was grand, never got hotter than the usual bit over 80c so I concluded it was normal. I never did try the bottle thing to test.

Dec

This is my thinking as well Dec. I ran it for a week without topping up and it was fine, no over heating etc. I will do a small bottle and see what happens.
Mine never gets to the 80c area, unless I am sat still for a while with engine running after it has been driven for a while. When I pull away again it drops down to just above the "quarter" mark and stays there.

John

 

[Dec]

If you drive for 4 or 5 miles on a straight road without too much traffic the needle should be at or slightly above 80c, if it’s below then your thermostat is sticking open and should be replaced.

Dec

 

[Crapshot]

If you drive for 4 or 5 miles on a straight road without too much traffic the needle should be at or slightly above 80c, if it’s below then your thermostat is sticking open and should be replaced.

Dec

Have changed the thermostat and car is running better! Gears change "better"? Car seems to be more responsive as well? Just need to see if the coolant level goes down again after a few days driving.

John