To leak or noto to leak

[Stephen74]

Ok, short story long...

Bought a cheap second hand car. Was concerned about the head gasket and the cooling system. Had it serviced by a local garage that had excellent reviews.

The day before the service my car was overheating. When my revs dropped to idle the oil light was coming on, the big red STOP light was coming on.
Took it in for the service and the garage said no problem with head gasket, no signs of a leak in the cooling system. Oil warning light doesn't come on.

Over the next week I noticed that my expansion tank was emptying, that I could hear a running water sound from the passenger side of the car when I accelerated, and that the passenger footwell was soaked with coolant. I took it back to the garage and they said it was a heater matrix problem, sucked teeth and would be expensive.

I crawled upside down in to the passenger footwell, saw that a bolt was missing from the pipes connecting to the heater matrix. Found a bolt, fitted it, no more leak. Carpet all dry.
Can still hear running water, expansion tank sometimes empties.

In looking for another leak I have discovered:
1. sometimes I find a giant puddle of water under the car.
2. sometimes there are no puddles of water under the car.
3. on a 75 mile journey I suffered no apparent loss of water from the cooling system.
4. on a 5 mile journey to work I lost at least 2 litres of water (thats what I put back in to top it off)

What the bloody hell is going on? Why is my coolant system emptying one minute then working perfectly fine the next?

[OchAye]

Random comments.

If the car is overheating you could have a stuck thermostat or it will overheat if the coolant system cannot be pressurised because of a leak.

1-4 too many random possibilities. If things are cold they will leak easier because metal will be shrunk whilst if hot it will be expanded. But when things are hot the pressure in cooling system should defeat any expansion contraction of the metals.

Given the loss of coolant you could have an airlock somewhere which would result in overheating.

If you have a leaking head gasket check the engine oil for "mayonnaise".

===========================
All in all, if you suspect it is more likely to leak on a short journey, drive to the supermarket and back (or equivalent) and get under the car to look for drips. There are so many different things that can leak :-(

[Stephen74]

The car doesn't overheat unless the coolant has been lost. The day it happened I didn't realise there was a leak and was probably running with little to no coolant. Though the temp never got in to the red, it did get close to the 100 mark.

Normally it runs between 70 and 90 (90 on the 206 is exactly at the halfway point of the gauge). 70 when moving, 90 when sitting in traffic.

There is mayonnaise under the filler cap but not on the dipstick. Two different garages have said no head gasket leaks. I've read comments from Peugeot owners that suggest these cars have a condensation issue which causes a similar effect to a head gasket failure.

How would the airlock cause there to be a water loss resulting in a puddle on the floor.

I may have found the problem. I had the expansion tank replaced as the previous one was filthy. Finally had a dry day yesterday and saw some water stains on a pipe below the expansion tank. It's possible the jubilee clip around the hose connecting to the tank isn't tight enough or maybe in slightly the wrong place. Felt around it this morning and it seemed wet. Can't get to it to tighten at the moment though.

[OchAye]

The car doesn't overheat unless the coolant has been lost.

That is fine then, normal.

There is mayonnaise under the filler cap but not on the dipstick.

OK.

How would the airlock cause there to be a water loss resulting in a puddle on the floor.

An airlock could cause overheating. But you have now eliminated the overheating. BTW. I did saw on the first line, "random comments"

I may have found the problem. I had the expansion tank replaced as the previous one was filthy. Finally had a dry day yesterday and saw some water stains on a pipe below the expansion tank. It's possible the jubilee clip around the hose connecting to the tank isn't tight enough or maybe in slightly the wrong place. Felt around it this morning and it seemed wet. Can't get to it to tighten at the moment though.

With bit of luck that is it then. Remember to add antifreeze to the water. It helps prevent rust inside the engine etc. and stop the coolant from freezing up.