Little update. After a busy Christmas period, and a bout of illness, I finally got to take the ZT out for a proper spin yesterday evening. Managed about 20 miles, no overheating issue, and the cabin heating was consistently lovely and warm.

Have checked coolant levels this morning and it all looks good. So hoping this is as simple as it being the coolant cap. I’ve ordered the O rings and will see how we go from there.

Fingers crossed.

Sorry to dig up my old thread, but it’s high time I sorted this issue. Since I’ve only been using the old girl to nip to the co-op and back I’ve left this far too long.

I’ve tried replacing the coolant cap, but it’s still losing the coolant over the course of around 10 days - 2 weeks. Car never gets to the point it overheats, so it was just the original incident I mentioned all those months ago.

I have noticed a little bit of mayo on the oil cap today, does this always mean HGF? Or would a perished inlet manifold gasket allow water to get into the oil? I have had it suggested that this could just be condensation from the minimal use the car gets?

If not, my next step is to change the inlet manifold gasket as suggested. Is this as simple a job as it looks? Just disconnecting, cleaning things up nicely and then fitting it all back together?

As ever any help and tips are greatly appreciated.

If the car is little used mayo can be caused by condensation, the engine doesn't get hot enough to burn it away.

Yep, replacing the IMG is straightforward. One other thing to be aware of with the 1.8 is the plastic inlet manifold has been known to warp, not by much but enough to cause a leak. Remove the manifold completely and check it with a decent size straight edge.

Do you have any paperwork to confirm that the head gasket has been replaced as such,if not then you must assume that it has not been done, meanwhile avoid driving the car over long distances and have it pressure tested at a good garage who actually know what they are doing, also check all the hoses and their retaining clips. The diagnostics test activation sequence should be listed in the How To section, good luck,

Before we get into the drama of head gasket failure, consider this:
Tom; as Steve has said, that's barely enough for the engine to reach normal temperature which may well explain the small amount of mayonnaise under the oil filler cap.

In post no. 8 I recommended use of the instrument pack diagnostics to discover whether or not the engine is reaching a proper temperature during your very short drives to the Co-Op. Did you ever do that?
If not, can you do it now?

Simon

I never got round to it, but I went further afield tonight. Round trip of about 18 miles, and there was no bother with the temp. I’ll give the temp diagnostic a shot in the morning and report back.

Small update.

No coolant lost since I topped it up yesterday morning. So the longer run it had yesterday evening didn’t see noticeable loss.

This morning I activated the diagnostic mode and took her for a spin to the co-op and back. She only got up to 66 degrees by the time I got there. By the time I got home again it was up to 80.

Thanks for this Tom. It demonstrates what Steve said in post no. 14. 66˚ in car terms is cold and 80˚ is still below thermostat opening temperature. These short runs will be taking a toll on your engine and fuel consumption will be high.

Can you repeat the test on a longer journey to see if the temperature rises to the nineties when the car's in motion and up to 104˚ when stationary for long periods?

Simon

Thanks, I will yes, I’ll use it this afternoon on a longer run and see how it gets on.