Mk 2.5 1.8 Sport coolant leak

[S7Paul]

Hi all,

My daughter's car has developed a coolant leak. At first I couldn't see any evidence of leakage (other than the level in the header tank dropping quite quickly), but having removed the strut brace and ferreted around with a torch & mirror, I can see coolant on the bottom of the length of wiring harness from the fuse box as it goes under the inlet manifold. There's also coolant around the starter solenoid terminals.

Trouble is, I can't actually see where it coming from. Does anyone know what's hiding under the inlet manifold that might be leaking?

[MX-5 Lazza]

It's likely to be a small hole in one of the heater pipes. If it's the one that runs behind the engine its a PITA to replace. However, if its one of these 2 its best to replace both anyway.

[S7Paul]

Thanks Lazza, I'll have a look.

[S7Paul]

Just to close this off, it was the hose that runs from the rear of the cylinder head, through the gap between the starter motor and inlet manifold, and terminates at the oil filter baseplate. Luckily, Autolink (who are fairly local to me) had one in stock. Even more luckily, I was able to replace it in just over an hour, only removing the front wheel, strut brace and one of its support brackets.

I found getting to the rear clip was fairly easy (it was a Jubilee clip - not sure if that's standard), though getting the hose off was more difficult (ended up slicing it lengthways with a Stanley to loosen it). Getting the front clip off wasn't too bad, and the hose pulled off with no problem, but getting the new one back on was a swine. The pipe it goes onto points slightly away from you, and you have to push the new hose on mainly by feel, and in a very confined space. That, and getting the clip back on, was the worst bit.

I think I only managed it because I could just about squeeze my arm up through the hole behind the wheel, lying with my head just behind the brake caliper. A more "powerfully built" person wouldn't have had a chance. I was just determined that I wasn't going to remove the inlet manifold just to replace a stupid little hose!