Mystery Collant Loss

My 2000 1.8 Freelander uses coolant at the rate of about 250ml every couple of hundred miles.

It's definitely not getting into the oil (no mayonnaise - and 'sniff' test all clear) and there are no obvious leaks.

I do notice that there are some deposits around the Expansion Tank filler cap - and when hot, some fluid around the top of the tank - but I'm not sure that this would account for the full coolant loss.

I know that inlet manifold gaskets are a weak point on these cars - but can't see any evidence of coolant loss around this. Is there a way of testing the gasket, without removing the inlet manifold?

Any thoughts greatly appreciated.

Cheers,

Ian.

You've obviously got a problem. You aren't likely to get full on mayo in the reservoir tank 'till the very end.

You need to pressure test the system to confirm there is an internal issue. You may find that it is a radiator leak which appears quite common now after the winter we had where incorrect levels/mixes of coolant were ineffective against the prolonged winter.

The inlet manifold needs to be replaced with a green gasket. A garage should charge around £100 to change one of these. If it's head gasket, then factor in ten times this amount to get it fixed properly. Include a new water pump and 12.5 hours of labour. Depends on how you do things - people on here have done it on half that somehow.

You can get a MIL light on if coolant is leaking past the inlet manifold, as the HO2 sensors get affected by the coolant.

Cheers WSLR,

I did wonder if coolant leaking past the inlet manifold would affect the O2 sensor.

May hook my OBDII up to it later and see how the O2 sensor readings look.

Cheers,

Ian.

the expansion filler tank cap is a known failure point, could be suprising how much coolant is escaping that way. might be worth changing the filler cap to see what happens. also look for some star fractures around the top of the filler bottle.

however, given that we are talking about a 1.8 I'd do all the other checks too.

Thanks Optimus Prime.

New expansion tank bottle cap sourced and fitted today. Will also check the neck of the bottle.

May see if I can turn the old cap bottle into a pressure tester!

It's funny, but there has clearly been a lot of coolant getting out this way - judging by the sticky residue around the base of the expansion tank.

Think I may be getting somewhere with this.

Yesterday, I slipped the yellow plastic collar off of the expansion tank to see what sort of shape the filler neck was in (where it forms the top part of the bottle).

The plastic looks very craked - a network of fine cracks radiating out from the filler neck.

Although these look to be deep within the plastic (not clearly evident cracks) I wonder if the material has sufficiently weakened to the point where it becomes porous.

Is this a common problem?

Cheers.

The wife met me from the station this evening in the Hippo. A really hot evening and it had been standing for a while.

As I walked around the front to get in, I was greeted with the unmistakable smell of warm coolant.

When I got home I got straight under the bonnet and, after a bit of prodding, I've narrowed it down to the bottom hose - where it joins the rad.

Job for Saturday, methinks!