Technical Heads-up about thermostat and heater hose

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Technical Heads-up about thermostat and heater hose

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This probably isn't 'news' as such - I think it's been mentioned here before - but here is a reminder anyway.

Our 500, 2008 1.4 Dualogic, had a slight coolant leak requiring a fortnightly top-up of perhaps 250mL - nothing to worry about? Also had a slight clutch judder that seemed to come and go.

Well, after a few weeks, I was changing the oil and performing a general service - and while I was under the car, a few red drips landed on me. Inspection revealed the drips were leaving the exhaust pipe, leaving a pink residue on the oxygen sensor, leading up the front of the gearbox to the culprit - a pipe on the thermostat.

I knew this hadn't been disturbed and so it was unlikely that a hose clip was loose (etc.) so I decided not to touch it until I had a replacement thermostat and a few replacement hose clamps on hand. This turned out to be the right decision.

I removed the undertray and disconnected the lower radiator hose to drain the cooling system. I removed the air box, the plugs from the ignition coils and various other plugs/earth lead connection, so that the wiring bracket could be unfastened from the cylinder head (three nuts) and moved aside.

The thermostat is then easy to reach - no need to remove the battery or the ECU - and as I removed the hose clip from the heater hose, the black plastic hose tail simply fell off the thermostat :eek: it was obviously getting ready to pop - the engine would have been cooked.

As a bonus, the clutch judder is clearing up nicely now that there isn't a continual trickle of oily red coolant going in through the clutch release lever.

The replacement thermostat (Facet brand) has steel hose tails; a much better idea.

I guess the moral of this is to carefully check any coolant leaks, no matter how small. The fix is easy, but needs to be caught in time!

-Alex
 

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Nice work!
I sometimes feel the "judder" comes on the 1st gear only, can this be a leaking too? (there;s a new robot unit installed only 10K km ago)
I need to fill the collant with about 30-50 ml every 2-3 months, depends on hot the weather is, iv'e also just got mine from service they said no leaking under the hood or beneath so it relaxed me a bit
 
Ahmett reports some slight coolant loss in a hot climate too; so I guess that's normal. I wonder if the pressure cap is suspect (excess steam being vented?)

The clutch judder - hard to know. Has the clutch been replaced without the flywheel being resurfaced? Are all engine mounts in good condition? I guess I've learned that it only takes a little contamination to upset it, so if there was a slight oil leak from the gearbox, that would explain it. How many total kilometres? We're just short of 100,000km and I would expect a new clutch to be required at 120-150,000. It would be wise to replace the gearbox input shaft seal at the same time.

-Alex
 
Same happened here. Must have been leaking for a while before failure. Next thing catalytic convertor pipe split ( may have been sudden cooling from failed term of pipe). This changed, Now engine management light is on. .... then found the flexi section of exhaust, changed in March had failed, This also changed but light still on...... I give up ��
 
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