Technical 1.4 16v (not MultiAir) coolant leak at manifold?

[alexGS]

Long-time members will know that I hardly ever have any problems with our 500 - a cracked pipe on the thermostat, and a bolt that fell out of the sunroof have been the only two problems in the last four years

However, similar to the time when I spotted the thermostat leak during a service, today I detected the smell of hot coolant when parking in the garage. I’ve seen some pink residue at the back of the cylinder head around the inlet manifold, passengers/left side of car (when seated in driver’s seat), and the coolant level is slightly down.

I’ll get a photo tomorrow and will document the disassembly/repair - before I do so, I just wondered whether anyone has noticed this before?

Seems there may be a plastic plug in the area where other similar engine versions have a temperature sensor fitted; I suspect this plug is leaking. I reckon it’s the usual ‘stitch in time’ scenario where a bit of inexpensive attention while the leak is small saves potentially expensive overheating damage.

Just for completeness, our 500 is a 2008 model, 1.4 16v 100hp Dualogic.

Cheers
-Alex

 

[alexGS]

Really hard to photograph - but it appears the leak is around a yellow plastic semicircular blanking plug - possibly where it meets the cylinder head, or maybe the plastic inlet manifold. Does anyone know please whether it can be sealed up or whether it needs replacing? That will help me decide whether to take it apart first, or order the parts first

Thanks
-Alex

 

[John202020]

How clean is your engine!?

If its a plastic plug I doubt it can be removed/fixed without it breaking in the process?

If possible I would remove parts to give better access to confidently confirm the problem?

 

[alexGS]

How clean is your engine!?

Thanks! lol - yeah, ten years and 130,000km have taken their toll - bit of oil around the breather that I’ve never worried about but I promise I’ll clean it up a bit

If its a plastic plug I doubt it can be removed/fixed without it breaking in the process?

If possible I would remove parts to give better access to confidently confirm the problem?

Yes - I agree, it has to come apart to see what’s deteriorated. The colour of the plastic looks aged so it’s probably that. I just thought I’d find out whether it’s a common problem and whether anyone knew whether it needed a new manifold, new plug, new gasket, or all three.

-Alex

 

[alexGS]

Well, I got onto this job today. First I removed the undertray and drained the engine coolant by removing the bottom radiator hose, which created an instant oily red mess all over the garage floor It sheets off the front structure over about 50cm width, so you really need a wide tray.

Taking the manifold off requires the removal of eight bolts - three that you can see, and five underneath that you have to do by feel. There’s a load of claptrap in the way of the ratchet handle, meaning extensions of two lengths, and of course you need hands that are both tiny and strong

In eLearn, FIAT say to remove the scuttle (base of the windscreen) which would mean wipers off spindles, trim off, etc. but I can confirm this is unnecessary. It does not help with getting a hand underneath the bulky manifold, particularly at the cambelt end where the A/C compressor prevents socket spanner access, necessitating a ring spanner turning the bolt one flat at a time.

Also, the engine wiring is tightly clipped in place so it obstructs the bolts underneath - you have to release two clips by feel (see third photo for where they are). Speaking of wiring - there’s no need to unplug the injectors - just undo one large plug on the end of the manifold and the wiring will come with it (still have to unplug a couple of sensors but you’ll see which). Brake servo and breather pipes must come off - Clic-clamp pliers are worth having - the throttle body can come off if you think it helps - an ordinary 8mm socket undoes the E-Torx bolts, but the one bolt you can’t see is inexplicably a 10mm hex with unused stud poking through it. Just to make it difficult.

Back to those wretched manifold bolts... A ratcheting ring spanner would help - but to make things more awkward, someone decided to use 11mm bolt heads (10mm is usual for M6 bolts; ratcheting ring spanner sets are 10, 12, 13 etc.) AND they decided to put thread-locking compound on (in the factory) to ensure that even when loosened, you can’t get them out with your fingers. So removing eight bolts takes about two hours.

Finally the culprit is revealed - a removable plastic plug (in aged, yellowed plastic) is not a tight fit against the cylinder head, and the compressed rubber seal leaks. First photo shows the crystalline deposits on the block and manifold.

The manifold is not heated and so this coolant passage serves no purpose on this model; the plug just has to seal it off. I will epoxy the plug in place to ensure it is fitted squarely, and fit a new seal, plus new seals for the four manifold branches.

Second photo shows the plug removed; note bolt locations and clips under manifold visible in third photo.

I expect this will become a common problem on the 1.4 16v as the orange rubber seals harden with age. It doesn’t seem that the plastic plug deteriorates; it just doesn’t fit very tightly by design, as a complicated shape leaves it only partially supported.

Fourth photo shows the amount of engine bay space vacated by the manifold; but also the obstacles that you have to work around.

Cheers for reading this far don’t be put off fixing it properly, but do expect it to take several hours...
-Alex