Under pressure

[Steve Williams]

Hi All

Took advantage of the change in weather today and went for a drive. Did about 60 miles in all but about 2 miles from home I thought I could smell coolant. I wasn't over heating or anything. Anyway I popped the bonnet to see coolant had been blasted out of my header tank overflow pipe. I spotted the other day a small leak from the top of my new radiator. Not huge but a slight leak. Its not the hose but just below. Would a small leak like this cause that kind of over pressurising. I have had the head gaskets checked a few weeks ago at a garage and they were okay.

Steve

[Jeff]

Hi All

Took advantage of the change in weather today and went for a drive. Did about 60 miles in all but about 2 miles from home I thought I could smell coolant. I wasn't over heating or anything. Anyway I popped the bonnet to see coolant had been blasted out of my header tank overflow pipe. I spotted the other day a small leak from the top of my new radiator. Not huge but a slight leak. Its not the hose but just below. Would a small leak like this cause that kind of over pressurising. I have had the head gaskets checked a few weeks ago at a garage and they were okay.

Steve

Hi Steve,

Depends on size of hole/leak. Don't forget the system is under pressure so the smaller the hole, the more the squirt, the pressure doesn't alter just the velocity, so a small hole would seem to be at a higher pressure when it actually isn't. Hope that makes sense.

Stag Parano...........

Jeff.

[Steve Williams]

Cheers Jeff

I was wondering if the leak would cause air to get into the system causing the loss of water out of the header tank overflow I have fitted. The radiator leak is only a trickle that drips down the neck then forms a small puddle before running down the side of the radiator. I forgot to mention that the coolant was also quite foamy coming out of the overflow.

[Jeff]

Cheers Jeff

I was wondering if the leak would cause air to get into the system causing the loss of water out of the header tank overflow I have fitted. The radiator leak is only a trickle that drips down the neck then forms a small puddle before running down the side of the radiator. I forgot to mention that the coolant was also quite foamy coming out of the overflow.

Hi Steve,

Do you have a header tank or a standard system?

If standard, then if you have a leak, which you do, air will be drawn back in instead of coolant from the bottle as air is easier and than the coolant.

Frothy? well, doesn't sound too good but I am sure someone else with more knowledge than me will advise.

Jeff.

[Steve Williams]

Jeff

I have a header tank set-up.

Cheers

Steve

[Jeff]

Sorry Steve,

Just re read your first and it says header tank.

First thing then is to sort out the leak.

If you checked a few weeks ago, doesn't nec mean anything, but if the head gaskets have gone you will get the pressure build up.

Sort the leak, then see how that goes. If the pressure builds up again, it could be a gasket, but don't want to frighten you.

Jeff.

[V Mad]

I dont see how a small leak could cause an overflow but if the cooling system was slightly overfilled ie there was not quite enough expansion space then the coolant has to be pushed out of the overflow. Not a problem providing it doesnt keep happening.

NB: Ethylene Glycol has a much higher expansion rate than water. If you use a high concentration of glycol antifreeze you need a much bigger expansion space.

[staginhiding]

Hi Steve
I know you have had ongoing cooling problems for a while now.The small radiator leak would not cause the overflow out of the system.
You have a pressure problem somewhere.And as you have done lots of other work to the system and various checks without sucess
I think sadly you might have the start of a head gasket problem

[Jeff]

Sorry all,

Of course the leak will not cause the pressure, read it last night after too many glasses of vino.

Sounds like Chris has said or gasket like I said hic.

Note to self, don't drink and write