Coolant problem - spluttery pop!

[rololux]

I've always had a slight coolant leak - nothing serious, just a few drops on the garage floor after a drive. Never tracked it down, but it has not been a problem as long as I top up the tank every few months. The car has been standing over winter and I fired it up again last weekend. Did all the usual checks, charged the battery and it started straight away, which made me happy! Took it for a gentle spin, then a more aggressive spin, then down to control technique (MOT to you), where it passed with flying colours. That was Tuesday.

Lovely morning today, so I thought I'd take it to work. I noticed that there was a little more liquid on the garage floor than usual, so checked the coolant tank again. It was low, but not much - maybe 1cm down from nominal. I opened the filler tank, and there was a big vacuum noise from the tank (like air was being drawn INTO the tank) and at the same time a big spluttery pop from the other side of the engine bay, somewhere near the turbo, or maybe the left hand side of the radiator. This is approximately above where the drops of coolant appear on the garage floor. Also noticed there is a small amount of white deposit around the coolant tank filler cap.

No time to investigate, so I decided not to drive it to work, a bit worried. What could cause this? The engine was totally cold. There cannot be any major leakage to the coolant system as there was obviously a good vacuum seal on the tank. Has a seal blown out or something? How can I proceed to check what it going on? I did notice that the temperature gauge never went up very far on Tuesday, but I put that down to the cold weather. The heater was working fine.

Any ideas much appreciated.

Roland

[muley]

Roland

I think you really need to pinpoint the leak. To do this I suggest you put a sheet of cardboard/paper under where the leak is; raise the car (careful - use axle stands) and find where the water is coming from. Chances are that it is the radiator - these can be recored for not much money. It could be a hose that might fail spectacularly soon! The other symptoms you mention may not be anything serious - but I suggest you fix the leak first.

Rgds

Jim

[rip]

My leaky radiator turned out to be caused by a failed head gasket. Hopefully this is not your problem too.
May be worth you getting a block test done for this?

[rololux]

I followed the advice (thanks), and got a compression test done. Very low compression on number 3. Could be head gasket, or the mechanic suggested a possible exhaust valve issue.

So the head has to come off - not cheap but glad I'm going to find out the cause. Without the car for another sunny week

[rololux]

The good news is that there is no problem with the head - all valves in good order - but the head gasket had gone. The bad news is that the dealer is having problem getting the right gasket, and it has been stuck in the garage ever since. It is a Lotus dealer, so I'm assuming he is going through official channels. Should I try and source one from alternative suppliers, and if so can I be sure to get an OEM part - I hear there are dodgy aftermarket versions around? If I have to wait for Lotus to come up with one, I guess this could be a long wait.

There is some incentive for the garage to sort this out soon though, as they have promised to keep the car in the workshop, rather than letting it leak in the carpark!

Roland

[Nickydee]

Hi Roland

Head Gaskets are not available from Lotus. They are on "back order" but with no indication of when they will become available. This has been the situation since Dec 2009, so I dont hold out much hope.

Have you seen this thread.

http://forum.lotuselancentral.com/viewtopic.php?f=37&t=16715

I sourced mine from Rock Auto in the States - no problems as yet!