Coolant Leak - Head Gasket Or Less Serious...?

[Moggs]

Hi all - I've just signed up, having a Focus and a Fiesta on the driveway. Wish I had found you beforehand. I hope that you don't mind me jumping straight in with a plea for help. Bad news today - the old Focus 1.8 zetec went in again to investigate a coolant leak that seems to have become a long standing problem, of one cause or another. 190k miles on the clock, so a good innings. Later years seem to have been dogged by leaking coolant - two water pumps in as many years. But for a good few weeks now I recall that the engine temperature has been quick to rise to 'normal' (the gauge doesn't go far above the normal temperature) but with a need for a regular top-up of coolant and a tell tale dribble under the car in the mornings. It has also started to have idle-run problems, with the engine stopping regularly at traffic lights on tick-over.

Last night, I had to charge the battery becaus of this (car hasn't been used for four weeks) and noted the coolant header bottle was empty. As fast as I put water in, it ran out, which was quite a shock! Seemed to be coming from the thermostat housing area and the leak had become clearly quite serious. Anyway, limped it down to local garage today and they reckon that the head gasket has gone, as there are traces of oil in the coolant (special detecting fluid used or some highly technical test....). I have a lot of confidence in these guys as they do take good care and have kept the old motor going for many a mile. I wasn't 't too pleased to hear this news though....

Resigned now to a sale for spares, I decided to have a closer look before the terminal decision. Here we go.... Have managed to remove the top two bolts of the t-stat housing but the lower one will not shift (now rounded head). I'll go to get some of those nice looking Irwin bolt grip extractors tomorrow and try to get the housing off. I just have an idea that if it was the head gasket, would the water run out so quickly? Would there be evidence of emulsified oil? (I can't see any). Could I be lucky enough to get away with a t-stat assembly? I know that there are no easy ways to diagnose these problems but would be grateful of your experiences! Maybe we can see 200k on the clock yet!

What next?

Thanks, in anticipation of a glimmer of hope.

Moggs

[troy45]

Not sure if a leaking head gasket would show up as coolant dripping onto the floor. would have thought a hose or other external leak to be more likely?

[Moggs]

Bolt gripper did the job (useful tools for those unfortunate momernts). Anyway - to cut a long story short, a new t-stat housing to manifold seal was useless as the inner seal retaining lip of the housing had apparently vapourised! Various trips to motor factors and a bit of fiddling about with tight bolts, seals and thermostats and eventually managed to put together a new t-stat housing body and use the existing thermostat cover (out of stock).

Refilled and ran engine up to temperature and....... no leak so far. Will get a few miles in before a flush and refill with a/f mixture. Thanks Troy.

Happy days :)

Now, about that idle speed engine cutting out.....

[troy45]

Bit of a job for you changing the t-stat body etc but lot less pain than having to change the head gasket.

Good news you've (probably) got to the bottom of the leak now :)

[Moggs]

Hi folks

Update to the 190k mile coolant leak - nearly one month down the line and no leaks. Quite pleased but it appears that the engine stall problem is proving too much for wifely driver.

1.8 16v petrol zetec.

I have cleaned the MAF sensor with contact cleaner and it has shown no improvement and now I'm a bit baffled as to what to do next. Lambda? Speed sensor? Pipes and fittings? I'm not sure which direction (or how) to go from here.

Symptoms are that engine runs fine until revs drop, on approachuing junction or coming in to park, even when changing down on low revs. Rev counter drops , engine shudders and stalls. Regularly - almost every similar situation.

Have changed plugs and air filter because they were probably due.

Your help appreciated.

Cheers.

[Stoney871]

When the engine power drops do you also temporarily lose speedo sigbal as well?

If so then definitely the speedo sensor.

[artscot79]

The thermostat housing being plastic is a weak point of the 1.8 head gaskets are not common as the engine will use 2 pistons as air pumps to cool the engine the idle control valve will cause youre stalling symptoms easy to change

[Moggs]

Thanks both - no speedo reads OK. Idle control valve sounds to be the culprit then as there is no.... ermm... idle control! Thanks.